Super Mario Bros. - 1985

Nintendo had already made their breakthrough onto the video gaming world stage in 1981 with Donkey Kong, the jump-and-run adventure game that established the platform game genre. In this kind of game, the player must navigate their character from one platform to the next by running, jumping or climbing. Developed for both the arcade environment and for various Nintendo game consoles, Donkey Kong was the game in which the character Mario made his first appearance. Mario made his next significant appearance in the Nintendo arcade game Mario Bros., released in 1983, this time accompanied by his younger brother Luigi. Having begun his existence in Donkey Kong as a carpenter, Mario was now an Italian-American plumber.

In Mario Bros., the protagonists are creatures that inhabit the sewers beneath New York. Mario must eliminate the creatures by flipping them over onto their backs and then kicking them away (Mario's brother Luigi is only involved in the two-player mode). Each time a creature is dispatched in this way, coins appear that can be collected by the player's character to acquire bonus points. Additional hazards appear in the form of fireballs that frequently move across or bounce around the screen, and icicles that form underneath platforms and have a tendency to fall from time to time.

Mario Bros. was not a huge commercial success, either in Japan or North America, perhaps partly due to the video game market crash of 1983. Nevertheless, the game subsequently found its way onto a number of different hardware platforms, including the Nintendo Entertainment System (NES), and survives in one form or another to this day. Perhaps more importantly, it enabled Nintendo's developers to try out a number of innovative ideas which were subsequently incorporated into the Super Mario Bros. game.

The game with which Nintendo of America (NoA) had gained their foothold in the North American video gaming market, Donkey Kong, had achieved its success largely due to the efforts of game designer Shigeru Miyamoto. Nintendo president Hiroshi Yamauchi obviously had considerable faith in the talents of Miyamoto as a game designer, because he gave him his own research and development division, and tasked him with developing the games that would also spearhead Nintendo's next foray into the North American market. Despite the relative lack of success of Mario Brothers, Miyamoto continued to develop games featuring the Mario character. This obviously included Super Mario Bros., for which he was both producer and director. His faith was more than justified when Super Mario Bros. became a huge success, first in Japan, and later in North America.

By 1985, despite the severe recession that had occurred in the North American video gaming industry in 1983, Nintendo were ready to attempt to build on their earlier success. The Famicom (Nintendo's Family Computer), an 8-bit home video game console, had been released in 1983 in Japan and was a huge success there. Nintendo hoped to repeat this success in North America with the Nintendo Entertainment System, which was essentially a version of the Famicom developed for the North American market.

There was, however, a problem. American retailers, who had suffered substantial losses as a result of the 1983 video game crash in terms of unsold games and game consoles, were unwilling to risk further losses. Nintendo therefore decided to take a huge gamble themselves. They agreed to supply the Nintendo Entertainment System to stores on the understanding that they would buy back any unsold stock. They even undertook to set up in-store displays, and demonstrate the capabilities of the new system to potential customers. An initial launch of the NES subsequently took place during the last quarter of 1985, although it was limited to retail outlets in and around the city of New York. The results were sufficiently encouraging for Nintendo to expand its marketing efforts to the rest of the USA.

The cartridge version of Super Mario Bros. was released in Japan for the Famicom in September, 1985, and immediately gained enormous popularity. It was released the following month in North America for the Nintendo Entertainment System. Although the game was not initially part of the NES game console package, Nintendo must have recognised its potential for increasing NES console sales because by the end of 1986 they were offering it as part of an optional system bundle. Hiroshi Yamauchi was fully aware that even the best game console hardware in the world is only as good as the games available for it, and he believed that Miyamoto's Super Mario Bros. would become as popular in North America as it already was in Japan. Sure enough, sales of Nintendo's home gaming console increased dramatically.

Super Mario Bros. was the game for an entire generation of video gamers, and it lives on in one form or another to this day. The original game can be played on the PC under Windows using an emulator. The one we used for the screenshots on this page is the open source NES/Famicom emulator Nestopia, which was developed for Windows by Martin Freij. There are also ports available for Linux and Mac OS X. If you want to try the emulator for yourself, you can download it from the home page at:

http://nestopia.sourceforge.net/

In order to use the emulator to play a game, you will need a copy of the game's ROM (legally acquired, of course). The opening screen allows the player (or players) to select either the one-player or the two-player version of the game. If the one-player version is chosen, the player controls Mario, and Luigi does not feature at all. If the two-player version is chosen, player number one controls Mario and player number two controls his brother Luigi. The two characters have identical abilities, and the sprites used for Mario and Luigi appear to be identical except for the colour of their overalls. Each player plays until they lose a life or the game is over, whichever comes first. Status information is displayed at the top of the screen throughout the game, including the current player's score, the number of coins collected so far, the current level, and the time remaining in the current level.

The ultimate objective of the game is laid out in the game manual in the following mission statement:

OBJECT OF THE GAME/GAME DESCRIPTION

One day the kingdom of the peaceful mushroom people was invaded by the Koopa, a tribe of turtles famous for their black magic. The quiet, peace-loving Mushroom People were turned into mere stones, bricks and even field horse-hair plants, and the Mushroom Kingdom fell into ruin.

The only one who can undo the magic spell on the Mushroom People and return them to their normal selves is the Princess Toadstool, the daughter of the Mushroom King. Unfortunately, she is presently in the hands of the great Koopa turtle king.

Mario, the hero of the story (maybe) hears about the Mushroom People's plight and sets out on a quest to free the Mushroom Princess from the evil Koopa and restore the fallen kingdom of the Mushroom People.

You are Mario! It's up to you to save the Mushroom People from the black magic of the Koopa!

In order to achieve this objective, Mario must overcome many obstacles, and either avoid or eliminate a variety of enemies. Needless to say, defeating one of these enemies earns the player points, whereas simply avoiding them doesn't. The game is over when the player completes all of the levels, runs out of time, or loses all their lives.

Many of the recurring features of the game are introduced in the game's first level. The first enemies encountered in this level are the Goombas. They look like mushrooms, and are encountered throughout the game. As with most of the enemies he faces, If Mario runs into a Goomba he will lose a life (unless he is currently a powered-up version of Mario, in which case he will simply revert to being the small version of Mario). They move backwards and forwards relatively slowly, however, and Mario can eliminate them simply by jumping on them. In fact, this is a tactic he can use to defeat most of his enemies.

You may have noticed the blocks, apparently defying gravity, that are suspended in the sky. Some of them simply look like sections of a brick wall, while others are marked with a large question mark symbol. If Mario jumps up and makes contact with one of the latter, a special game item will be released. Usually, the item will be a coin, which is worth two hundred points. Coins can sometimes be hidden behind normal blocks as well. Collecting a hundred coins gets you an extra life.

Sometimes, the item will be something a little more interesting that can bestow special powers - for a while, at least. A Super Mushroom, for example, is worth a thousand points, and turns Mario into a bigger version of himself (a Super Mario, in fact!) providing he can make contact with it once it has been released. There is also a 1-Up Mushroom which gives Mario an extra life, although these are quite rare.

Once in his Super Mario form, Mario can encounter a Goomba without losing a life, although if he does encounter one he will shrink back down to his normal size and be vulnerable again. Another advantage of being in this larger form is that Mario can jump up and smash the brick blocks to earn extra points.

Mario can also earn extra points by defeating more than one enemy at a time, usually by jumping on them, although the timing has to be just right or he could run into an enemy instead and lose a life. He must also be careful not to fall down one of the many gaps that appear on each level. That too will result in him losing a life, whatever form he is in.

The second enemy Mario will encounter on the first level will be the Koopa Troopa, which is a small turtle that retreats into its shell when jumped on. Once in this state, Mario can kick the Koopa Troopa along the ground to eliminate other enemies (including other Koopa Troopas). Mario must be careful not to get in the way of one of these shell projectiles himself, however, since they will bounce back off walls and other obstacles. In his large form, he will revert to his small form if struck by a shell, but if struck whilst in his small form he will lose a life. The Koopa Troopas are usually green, but some of them are red. The red ones behave slightly differently in that they will turn back from the edge of a gap if they encounter one, whereas the green ones will just keep going and fall in.

One of the really useful items Mario can discover hiding behind a block is the so-called Starman (presumably because it is shaped like a star). If Mario manages to touch a Starman, he earns an additional one thousand points and becomes invincible for a short time (although he can still lose a life by falling down one of the many gaps). In this state, he can simply run through any enemies he encounters and they will be eliminated.

Another very useful item encountered in this first level is the Fire Flower. Like other special items in the game, it can be found hiding behind one of the brick blocks. Although it looks fairly innocuous, if Mario can get hold of this plant he not only gets one thousand extra points, he also acquires the ability to throw fire balls. If he runs into an enemy in this powered-up state, he does not lose a life, but reverts back to being small Mario.

In each of the thirty-two levels in the game, Mario must deal with all of the enemies, obstacles, and pitfalls, and get to the end of the level. There, he will encounter a flagpole standing before a small castle. The flag flying on the flagpole is that of King Bowser Koopa, the king of the Koopa tribe (usually referred to simply as Bowser). Mario must take down the flag by jumping onto the flagpole, after which he will enter the castle, and the level is complete. The higher up the flagpole Mario manages to jump, the more points he will earn. Play will continue straight into the next level without a break although you can of course pause the game if you need to. You can also save the game at any point on the emulator version, although this was apparently not possible on the original NES console.

The Super Mario Bros. playing environment is organised into eight "worlds". Each world consists of four levels. To complete each level, Mario has to overcome or avoid the enemies, pitfalls and other obstacles in that level, and reach the flagpole at the end of the level. Each level, in each world, takes place in one of five different settings. The first level, as we have already seen, takes place in the "Overworld" setting, which as the name suggests is above ground. The blue background used in some of these levels presumably represents the sky, and was unusual for video games of the time. A black background was more often used for video games, as it was thought to reduce eye strain.

The second level of World 1 takes place in the "Underground" setting, and as you might expect uses the more traditional (for the time) black background. A new enemy is introduced in this level - the Piranha Plant. This carnivorous plant lives in pipes, and if Mario is standing on the pipe when it emerges he will lose a life (or revert to his small form if powered-up). He can't kill Piranha Plants by jumping on them.

Level two also introduces a new kind of obstacle - the moving platform. The platforms appear in gaps that are too wide to jump over, so Mario must jump onto one of these moving platforms in order to get across the gap. Not too difficult if you can get the timing right - you just need to make sure you don't land safely on the other side, only to run straight into an enemy.

Pipes serve another purpose in the game, apart from providing a home for the deadly Piranha Plant. They act as conduits - for example, between one level and the next. Pipes are also sometimes used to access hidden rooms and levels. Very occasionally, Mario can use one of these pipes to skip ahead to a higher level in the game.

In level three, we encounter a new kind of environment called the “Athletic” setting, probably because Mario must negotiate platforms set at various heights, sometimes using moving platforms, and all the while avoiding or eliminating the usual assortment of enemies. This setting seems to be an outdoor setting, since there are blue skies and clouds once more.

A new enemy appears here - the Koopa Paratroopa. Like the Koopa Troopas, these creatures are turtles. They look exactly like the Koopa Troopas, except that they have wings and can fly. There are two varieties. The red Koopa Paratroopas fly up and down, but otherwise don't appear to do much. The green Koopa Paratoopas are somewhat more erratic in their behavior, and sometimes fly at Mario without warning. If Mario jumps on a Koopa Paratroopa, regardless of type, it will lose its wings and become an ordinary Koopa Troopa (hitting a Koopa Paratroopa with a fireball has the same effect). It can then be dealt with in the usual way.

The fourth and final level in each of the eight worlds takes place in the “Castle” setting: As the name suggests, the action takes place within a castle. New obstacles are encountered here, including what appear to be pits full of molten lava that Mario must jump over or suffer a fiery fate. This would normally present no problem, but some of these pits are guarded by a rotating Firebar - essentially a stack of fireballs. The Firebars are found in other locations within the castle as well. They can vary in length, and may rotate either clockwise or anti-clockwise. They are often arranged in tandem in order to make it more difficult for Mario to avoid them. If he touches one, he will lose a life (or, if powered-up, revert to being small Mario).

If he manages to avoid the Firebars, Mario must still watch out for the fireballs that seem to be coming out of nowhere. The source of these fireballs turns out to be a fierce looking creature that looks like Bowser, and who is guarding a bridge over a river of molten lava. It turns out that this is, in fact, a False Bowser - a decoy created by the real Bowser.

Mario must somehow avoid the clutches of this False Bowser, as well as avoiding the fireballs he is unleashing, and get to the other side of the bridge. Alternatively, he can defeat the False Bowser in combat if he has the ability to throw fire balls. Once across the bridge, he can use the axe, which is (rather conveniently) waiting there, to destroy the bridge. Mario must jumps on, or otherwise makes contact with, the axe. This will make the bridge retract towards the left-hand side, causing the hapless False Bowser (assuming Mario hasn't already disposed of him) to fall into the river of molten lava.

The “Princess” rescued by Mario in the final level of each of the first seven worlds also turns out to be a decoy, placed there by Bowser. Although each of them expresses their gratitude for being rescued, they are in fact all Mushroom Retainers - described in the game's documentation as “Seven Mushrooms who originally served in the court of Princess Toadstool, but are now under the spell of the evil Koopa King”. Needless to say, the real Princess does not put in an appearance until the last level of the final world!

The first level of World 2 is another Overworld level, with enemies we have seen before. One of the features Mario may encounter here, as well as at other locations in the game, is a Beanstalk (sometimes called a Magic Vine), which is hidden behind one of the blocks. The beanstalk grows rapidly, allowing Mario to use it as a ladder to climb up above the clouds. Once there, he can earn extra points by collecting coins. Another new feature, which appears right at the end of this level, is a large spring that Mario must jump on in order to get over the final wall.

Level two in World 2 introduces a new environment - the “Underwater” setting. This level is actually fairly easy to get through. Mario can swim from the bottom to the top of the water, and although he still needs to avoid any enemies that appear in order to make it through the level, this is not really too difficult. There are two new enemies that appear in this level, both of which will be seen again in later “Underwater” levels. The Blooper is a squid-like creature that tends to chase after Mario. The Cheep-Cheep is some kind of fish, although its lateral fins appear to be able to double up as wings, as we shall see shortly. The Cheep-Cheeps may be coloured red, green or grey.

The third level in the second world takes place in an “Athletic” setting. There are the usual gaps to jump across, but this time no moving platforms. There are a large number of jumping Cheep-Cheeps however, so Mario needs to be careful in order to avoid them.

The final level of World 2, as in all of the other worlds, takes place in the “Castle” setting. There is the usual array of Firebars, and at the end of the level, Mario again has to defeat one of the False Bowsers. The only new enemy introduced in this level is the Podoboo. The Podoboos are essentially just big fireballs that jump out of lava pits. If one of them hits Mario he will lose a life (or, if powered-up, revert to being small Mario). They are not all that difficult to avoid, however.

The first level in World 3 takes place in the "Overworld" setting. This time the action must be taking place at night because, although there are clouds in the sky, the background is black instead of blue. We meet another new enemy here - the Hammer Bros. These are Koopa Troopas that walk upright, usually appear in pairs, and continually throw hammers in Mario's direction. They also occasionally jump.

We meet another enemy for the first time in the first level of World 4. This particular enemy actually takes three different forms. The first of these is the Lakitu, a spectacle-wearing Koopa Troopa that rides along on top of a small cloud. It hovers over Mario, tracking his movements. It also drops Spiny Eggs (the second form of this enemy) at regular intervals, which land in Mario’s vicinity. If one of these eggs touches Mario, he loses a life (or, if powered-up, reverts to being small Mario). Once on the ground, each Spiny Egg will hatch immediately into a Spiny (the third form of this enemy). The Spiny is a small red Koopa Troopa with a spiked shell. Unlike other kinds of Koopa Troopa, Mario can’t kill this creature by jumping on it. If he does so, he will lose a life (or, if powered-up, revert to being small Mario). They can be killed using fireballs, but it’s probably easier to just avoid them.

Another enemy that appears for the first time in World 4 is the Buzzy Beetle. Like the Koopa Troopa, this is a small turtle that hides in its shell when jumped upon. Unlike the Koopa Troopa, it is immune to fireballs.

I always have lots of problems getting past level three in World 4 - I never seem to be able to make the jump onto one of the high platforms (probably due to my extremely poor coordination). I am ashamed to admit that I have sometimes cheated by using the Warp Zone at the end of World 3 to go straight to World 5!

In World 5, Mario encounters the final two enemies (apart from Bowser himself, of course). The first of these is Bill Blaster, a cannon that Mario cannot destroy (although if he gets close enough to it, it will temporarily cease doing what it does most of the time, which is to shoot bullets. These bullets, of which there seems to be an endless supply, are called Bullet Bills, and appear to have eyes and arms. Mario can eliminate them by jumping on them or by running into them when he is in the Starman mode. If a Bullet Bill hits Mario, he will lose a life (or revert to his small form if powered-up).

The levels become gradually harder to beat as you get closer to the end of the game and that final confrontation with Bowser, but there are no new enemies after World 5. As usual, the final level of World 8 takes place in the “Castle” setting. In order to get to Bowser, you have to go through at least two pipes and an underwater section in which, somewhat strangely, the main obstacle is a series of Firebars! Once you are through this section, there is a Hammer Bro to overcome before you can finally do battle with King Bowser himself. The King looks remarkably like all the False Bowsers Mario has met previously, except that he is far more heavily armed and thus more difficult to defeat. Once Mario does manage to defeat him, he will finally meet the real Princess Toadstool!

If you manage to complete the game, you can undertake an additional “quest”. This is essentially just an opportunity to replay a world of your choosing. Don’t expect an easy ride, however, because the level of difficulty increases significantly for the extra levels. In addition to bonus worlds, there are also hidden levels and secret rooms scattered throughout the game, just waiting to be discovered. One of the best-known of these hidden levels (among seasoned gamers, at any rate) is the so-called Minus World. This hidden stage is labeled World -1, and it can be accessed from the second level of World 1 via a hidden warp zone. It is an underwater stage that goes on indefinitely - going through the exit pipe at the end of the level simply takes you back to the start of the level!

What made Super Mario Bros. such a popular game? Probably a number of things. Miyamoto was the creative genius behind it, of course, but he was aided by co-designer Takashi Tezuka, who joined Nintendo in 1984 and at the time of writing is still producing games for them. He and Miyamoto would first produce the design for each level on paper, and then pass it to the programming team - Toshihiko Nakago, Kazuaki Morita and Yasunari Nishida. The action takes place, by design, over a number of screens in each level, as Mario progresses from left to right within a kind of sliding window. This side-scrolling concept was still relatively new, and opened up almost limitless possibilities in terms of making the best use of screen space. In particular it allowed for the development of game backdrops that could extend way beyond the physical borders of the screen, and a much more diverse cast of characters.

The degree to which players can interact with a game is obviously an important factor in determining how well it will be received. In the case of Super Mario Bros, the level of interactivity set new standards. Players could exercise a significant degree of control over the movements of their character, Mario (or Luigi). He could walk, run, jump, crouch and swim. The behavior of non-player characters in the game was intelligent, if ultimately predictable, and made for gameplay that was both stimulating and challenging. The graphics were pretty good for their time, and the side-scrolling model allowed for a highly dynamic environment. And of course, the unforgettable musical themes produced by Koji Kondo (who wrote them after having been shown prototype versions of the game) have achieved almost classical status. Indeed, some of them have been performed by concert orchestras!

Super Mario Bros. popularized the side-scrolling model of video gaming, and has been hugely influential in terms of video game design. It has even been credited with restoring the fortunes of the North American video gaming industry in the wake of the 1983 video game market crash. According to some gamers and gaming industry officionados, Super Mario Bros. is quite possibly the best video game ever created. There is no doubt that it is certainly one of the most successful console games ever produced. It sold something in excess of forty million copies worldwide, excluding various ports and remakes. This was a record for a single-platform console game that endured for many years. It has only relatively recently been overtaken by Wii Sports, which was released for the Wii in 2006 (more than eighty million copies sold at the time of writing).

Meanwhile, Super Mario Bros. has been ported to just about every platform imaginable, including an arcade version, and has given rise to countless sequels. The original game has been re-released on several occasions, and is available today for both the Wii family of game consoles and the Nintendo 3DS portable game console. Altogether, over two hundred video games have been produced that feature the Mario character, which between them have generated sales of well over two hundred million units, making the Mario gaming franchise the most successful of all time.

Although the game introduced a number of new characters, it is Mario himself who has had the biggest cultural impact. Quite possibly the most celebrated video game character of all time, he has inspired television shows, comics, children’s books, and a vast array of merchandise. In 1990, the results of a Q Scores consumer survey in the US suggested that Mario was “more recognisable to American children than Mickey Mouse” (these surveys are postal surveys developed by Marketing Evaluations Inc. of Hassett, NY). There was even a Hollywood film based on Super Mario Bros. Released in 1993, Super Mario Bros. starred Bob Hoskins as Mario and Dennis Hopper as King Koopa (i.e. Bowser). The film itself was a commercial failure, but it established a precedent for making films based on video games.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Tetris - 1984

Tetris is probably one of the most addictive computer games in the history of computer gaming. The modern origins of Tetris, however, go back at least as far as the beginning of the twentieth century. The underlying concept is based on mathematical puzzle games in which geometric shapes are used to completely fill a square or rectangular area without leaving any gaps. The precise origins of such puzzles are a matter for speculation, but they could well date back hundreds, or even thousands of years. The particular class of puzzle in which we are interested involves geometric shapes called polyominoes. A polyomino is a two-dimensional shape consisting of an arrangement of n squares of uniform size. Each square must have at least one edge in common with one of the other squares. The word polyomino is an abstraction of the word domino, the name given to the rectangular tiles used in the game dominoes, each of which consists of two squares (the game of dominoes itself is thought to have originated in China during the thirteenth century CE).

The kind of polyomino we are interested in with respect to common mathematical puzzles is called a pentomino. As the name suggests, a pentomino is a shape created using five squares of uniform size, arranged in the manner previously described. The name pentomino, along with the names of other polyominos, is believed to have been coined by the American mathematician and professor of electrical engineering Solomon W Golomb, who reportedly introduced the name in a talk given to the Harvard Mathematics Club in 1953. Of course, the shapes themselves had been around for a lot longer.

One of the earliest known puzzles involving pentominoes appeared in a mathematical puzzle book published in 1907 entitled The Canterbury Puzzles and Other Curious Problems, written by English author and mathematician Henry Dudeny. In all, there are eighteen pentominoes. Of these, twelve are referred to as free pentominoes, which means that they cannot be obtained by rotating, reflecting or translating one of the other free pentominoes. Each of the remaining six shapes is a mirror image of one of the free pentominoes. By convention, each of the free pentominoes is named using the letter of the alphabet which it most closely resembles.

In some cases, it is fairly easy to see the correlation between the shape of the pentomino and the letter after which it is named. For the shapes labelled N, X and Y, you need to picture the shape rotated forty-five degrees clockwise. For the shapes labelled V and W, you need to imagine the shape rotated forty five degrees anti-clockwise. The remaining six pentominoes are reflections of the free pentominoes F, L, N, P, Y and Z. They are by convention labelled F', J, N', Q, Y' and S, and are called chiral pentominoes. This means that they are not identical to their mirror images, and therefore cannot be mapped to their mirror images using rotation or translation alone.

Common pentomino puzzles usually involve completely filling a rectangular space using pentominoes. In one common puzzle of this type, the rectangular space must occupy sixty squares. The rules state that each pentomino shape must be used exactly once, and no gaps should be left in the rectangular space. Some examples are shown below. Note that, since all of the shapes consist of identical squares, we have used different colours to differentiate between them. Note also that it is a particular property of pentominoes that a complete set of twelve pentominoes containing no duplicates (i.e. one and only one of each type of pentomino) can be used to fill a rectangle completely, with no gaps or overlaps. This is not true of other polyominoes such as (for example) hexominoes (polyominoes consisting of six squares) or tetrominoes (polyominoes consisting of four squares). Similar types of puzzle do not exist for these shapes, simply for that reason.

Those of you who are familiar with Greek (or at least with the use of Greek words to prefix the names of regular geometric shapes) will of course realise that a game called "Tetris" is unlikely to feature pentominoes, since tetra in Greek means "four". You may also have surmised that the game will feature tetrominoes, which are of course polyominoes made up of four identical squares. If you have ever played Tetris, you will probably appreciate that using pentominoes would make the game very much harder to play, whereas using trominoes (polyominoes formed using three squares) would make it far too easy. Using tetrominoes, we have a sufficiently large set of shapes to make the game challenging, without making it virtually unplayable. The complete set of tetrominoes is shown below. Note that the colours we have used for each shape conform to the standard laid down by The Tetris Company (more about them later). Note also that the shapes labelled J and L are mirror images of one another, as are the shapes labelled S and Z.

It is perhaps not particularly surprising that a video game based on mathematical puzzles of the kind described above emerged for arcade machines, game consoles and personal computers. What is somewhat unusual is that this particular game was developed in the former Soviet Union, at a time when most game development was taking place either in the United States or Japan. The idea for Tetris came from Moscow-born computer engineer Alexéy Leonídovich Pájitnov. When the game first appeared during the summer of 1984 Pájitnov, who was twenty-eight years old at the time, was working for the Dorodnitsyn Computing Centre of the Soviet Academy of Sciences (CCAS), a Soviet research and development establishment. The computer hardware on which Pájitnov initially developed the game was an Elektronika 60, which was essentially a Russian clone of the Programmed Data Processor (PDP) mini-computer manufactured by the Digital Equipment Corporation (DEC). In that respect, the hardware was very similar to that used to create the landmark game Spacewars! at MIT in 1962.

Pájitnov was aided in his efforts by friend and fellow computer engineer Dmitry Pavlovsky (who had himself designed several games on mainframe computers) and sixteen-year-old high-school student Vladimir Gerasimov (who at the time of writing is working as an engineer with Google). Gerasimov was working at the computing centre as part of his school computer science studies, and came to the attention of Pavlovsky whilst working on a directory encryption program for DOS on an IBM PC. It was Pavlovsky who introduced him to Pájitnov, presumably because all three had an interest in developing computer games. Pájitnov is said to have come up with the name Tetris by combining the first part of the word tetromino and the last part of the word tennis (apparently he was a big tennis fan). Due to the limitations of the Elektronika 60's hardware, the game's "graphics" were created using ASCII characters. The tetrominoes, for example, were produced using pairs of square brackets grouped together.

In the game itself, tetrominoes appear in a central position at the top of the screen one at a time and fall, slowly at first, down a vertical shaft. In versions written for the IBM PC and other personal computers, the player uses various keys on the keyboard to move each tetromino left or right, to change the orientation of the tetromino (by rotation), or to cause the tetromino to fall immediately to the bottom of the shaft. The rate of descent is such that each tetromino falls through a distance equivalent to the height of one square in a pre-determined time interval. Once the tetromino is at the bottom of the shaft its orientation cannot be changed, and it cannot be moved left or right. The idea of the game is to try to ensure that the blocks fall in such a way that the bottom row is filled with squares. If this is achieved, the complete row of squares will disappear, causing anything resting on top of it to fall by one row, and creating space for incoming tetrominoes. In some cases, more than one row can be completed at the same time, up to a maximum of four. All completed rows will disappear, and any rows lying above them will move down to fill the gap that is left.

Although hundreds of versions of Tetris have been produced over the years, most follow the same basic format. The playing area (the shaft or well) is ten squares wide by twenty squares high. The tetrominoes (of which there are seven different types) appear in a random order. Each sideways move by the player shifts the tetromino left or right by one square, and each re-orientation rotates the tetromino through an angle of ninety degrees clockwise. A row is complete when every available square space on that row is occupied by one square component of a tetromino. If the player fails to clear the rows quickly enough, the tetrominoes will eventually stack to the top of the shaft, and the game is over. Tetris is one of those games which at first sight looks relatively easy but turns out to be quite taxing. The object of the game is usually grasped by first time players immediately, without the need for lengthy explanations. The combination of simple rules and the relentless challenge presented by the game have the effect of making it highly addictive.

The game enters a new level after a given number of rows have been cleared. This usually means that more points are awarded for clearing rows, but it also means that the tetrominoes will fall faster. The player therefore has less time to position the tetrominoes, and it becomes harder to prevent them from stacking up to the top of the shaft (this is sometimes referred to as "topping out"), which of course ends the game. Once a player is happy with the lateral and rotational orientation of the current tetromino, they can use the designated keystroke to make the tetromino drop into position immediately. The player also has the option of seeing a preview of the next tetromino scheduled to appear at the top of the shaft. The preview facility gives the player the advantage of being able to plan their next move in advance, but may also mean that fewer points are awarded.

Although the way in which points are awarded varies considerably between different versions of the game, most implementations award a certain number of points for each row cleared. Additional points are usually awarded for clearing multiple rows in a single move, and the number of points awarded usually increases with each level. As you can see from the above screenshot, the original DOS version of the game has a relatively small number of commands available. Rotation of the tetromino is always clockwise, and the preview function is limited to the next tetromino to fall. The player's current score, level and total number of lines cleared is displayed at the top of the screen on the left hand side. Statistics detailing the number and type of blocks encountered are shown at the right-hand side.

The version of Tetris illustrated above is a DOS version written for the IBM PC by Vadim Gerasimov. It is available for download free of charge from Gerasimov's website. Pájitnov had originally intended to sell the computer games produced by himself, Pavlovsky and Gerasimov, but attempts to do so met with failure. Private enterprise was, after all, hardly the sort of thing that was encouraged in the former Soviet Union. Instead, the three would-be entrepreneurs ended up giving free copies of their games, including Tetris, to friends and associates. These friends and associates passed the software on to others, and Tetris began to appear on computers all over Moscow. Within a relatively short time, it was being played all over the Soviet Union. Tetris eventually found its way to the Hungary Institute of Technology, where programmers working for the institute created versions for other personal computer systems, including the Apple II and Commodore 64. It was here that the game first came to the attention of a representative from the mainstream gaming industry, Robert Stein.

In 1986, Stein was visiting the Hungary Institute of Technology in his capacity as a director of Andromeda Software, a British software publishing company that had strong links with the Eastern Bloc. Stein saw Tetris, and immediately recognised its potential. The copyright notice on the software led Stein to contact the CCAS in Moscow to try and obtain rights for the game. CCAS, with no previous experience of setting up this kind of deal, assigned Alexéy Pájitnov the task of negotiating with him. Stein allegedly offered Pájitnov an advance of one hundred thousand pounds sterling for the rights to publish the game for home computers, and received a response from Pájitnov indicating that the Computing Centre would be interested in coming to some arrangement. On the strength of this exchange, and with absolutely nothing agreed in writing, Stein sold the UK rights for the personal computer version of Tetris to software publishing company Mirrorsoft, which was owned by Robert Maxwell's company Pergamon Holdings. He sold the US rights to Spectrum Holobyte, a US software publishing company based in Alameda, California. Interestingly enough, this company was also later acquired by Robert Maxwell.

What followed was a somewhat chaotic series of events. Indeed, it is difficult to know exactly what happened, as different accounts tell somewhat different stories. Suffice it to say that both Mirrorsoft and Spectrum Holobyte were working under the impression that they had acquired legal rights to publish and distribute Tetris, an impression which at that time was completely false. Late in 1986, Stein sent a contract to the CCAS and even flew to Moscow to ensure that it was signed. Unfortunately for him, the Russians were not prepared to be steamrollered into signing anything until they could assure themselves that they were getting the best possible deal. Frustrated, Stein allegedly tried to circumvent the Russians by making a deal with the Hungarian programmers who had been responsible for porting the game to other platforms. Whether or not this is true, there is no record of any deal being struck in Budapest. Meanwhile both Mirrorsoft and Spectrum Holobyte were making plans to release Tetris for various personal computer platforms, including the IBM PC, Commodore 64, Atari ST, Amiga, and Apple II.

Spectrum Holobyte's IBM PC version of the game was released in the US in 1987. It featured background images that reflected the fact that the game had originated in the USSR. This version of the game is featured in the screenshot below, and is available for download from the AbandonwareDos website. In the same year, Robert Stein finally secured a licensing agreement from Pájitnov that allowed Andromeda to publish and distribute Tetris for the IBM PC and other personal computers. Unfortunately for him, it turned out that Pájitnov was somewhat exceeding his authority in this respect. At that time, the only organisation actually authorised to sell software originating in the Soviet Union to a foreign buyer was Elektronorgtechnica (usually abbreviated to ELORG). Stein found himself having to renegotiate with ELORG for rights he thought he had already secured, and which he had already sold to various third parties. In the first half of 1988, after protracted negotiations with ELORG director Alexander Alexinko, Stein eventually secured the rights to publish and distribute Tetris for personal computers. The agreement explicitly excluded rights to produce arcade and hand-held game console versions.

Later in the same year, Stein was still trying to negotiate with ELORG for the home console, handheld, and arcade rights. This time around he was dealing with Nikoli Belikov, who had been assigned by ELORG to re-examine, and if necessary re-negotiate, the existing contract. Belikov was also empowered to negotiate new contracts. He was not particularly impressed by the fact that Andromeda Software (Stein's company) had not fulfilled their contractual obligations to ELORG, having failed to comply with the agreed payment terms. Meanwhile, another player had entered the story. Henk Rogers was born in the Netherlands in 1953 but spent much of his early life in New York. He moved to Japan in the late 1970s and established his own software publishing company, Bullet Proof Software. Rogers became involved in the story after seeing a prototype version of Tetris in January 1988 at the Consumer Electronics Show held in Las Vegas. He recognised the enormous potential of the game immediately.

Rogers was well aware that Nintendo were about to release their new handheld console Gameboy, and felt that Tetris would be the ideal game to bundle with it. He initially approached Robert Stein to try to negotiate the rights for the handheld version of Tetris, mistakenly believing that Stein held those rights (which of course he didn't). It should be pointed out at this point that Bullet Proof Software believed they had already obtained the rights to produce game console and home computer versions of Tetris in Japan from Spectrum Holobyte, who in turn believed they had obtained those rights from Stein. Bullet proof Software consequently produced a version of Tetris for Nintendo's Famicom console (Famicom, short for Family Computer, is the name under which the Nintendo Entertainment System was marketed in Japan). To complicate matters even further, Mirrorsoft had sold exactly the same rights to Atari for both the Japanese and North American markets. Tengen (a subsidiary of Atari Games specifically set up to produce game software for the console market) had produced its own console version of Tetris for the Famicom. The resulting legal battles between Nintendo and Atari would drag on until 1993.

After several months of negotiating with Stein and getting nowhere, Rogers had had enough. He resolved to try and negotiate directly with ELORG. Stein, probably realising what Rogers was planning, decided to fly to Moscow to secure the handheld and console rights for Tetris. Meanwhile Mirrorsoft, who had no doubt begun to question the legitimacy of the rights they had obtained from Stein (and which they had already sub-licensed to Atari), were also planning a more direct approach. As it turned out, Henk Rogers, Robert Stein and Kevin Maxwell (Robert Maxwell's son, representing Mirrorsoft) all arrived in Moscow during the same week in February 1989. Rogers somehow managed to get to see Nikoli Belikov before either of his rivals. The meeting produced some unexpected revelations for both men. Belikov was taken aback when Rogers presented him with a Famicom cartridge version of Tetris. Rogers was equally surprised when Belikov informed him that the console rights for Tetris had so far not been licensed to anybody.

The result of the meeting was that Belikov's suspicions, that Robert Stein had not been entirely honest with him, were confirmed. His assessment of Henk Rogers, on the other hand, led him to believe that here was someone with whom he would be happy to do business. Kevin Maxwell was not too well received, probably because of Robert Maxwell's ongoing efforts to use his (not inconsiderable) political influence to put pressure on ELORG via his contacts in the Soviet government. To cut a long (and very complicated) story short, Rogers walked away with the handheld rights for Tetris. Stein retained the personal computer rights, but with a much more tightly defined contract that spelled out exactly what could and could not be considered a "personal computer" under the terms of the contract. He also reportedly obtained the arcade rights. Maxwell walked away with nothing other than the option to make an offer on any rights for Tetris that had not already been assigned.

As stated above, Stein supposedly came away from his meeting with Belikov with the arcade game rights for Tetris. This information appears to contradict sources that claim that the arcade rights had already been awarded to Atari during the previous year (1988). Atari Games certainly released an arcade version of Tetris in 1988, but there appears to be no hard information concerning how exactly they acquired the rights allowing them to do so. Since there is also no mention of Atari having entered into any direct negotiations with ELORG, these rights were presumably the subject of a deal between Atari and Mirrorsoft, or perhaps between Atari and Robert Stein. Atari do not appear to have faced any legal challenges concerning the arcade version of Tetris, as far as we can ascertain.

Having secured the handheld rights on behalf of Nintendo, Rogers proposed a similar deal to Nintendo for the console rights. In March 1989 Nintendo, via Rogers, made ELORG an offer which was duly accepted. Mirrorsoft did not attempt to match the offer. Having secured sole rights for the console version of Tetris, Nintendo demanded that Atari cease production and sales of their console version. After a brief and unsuccessful legal challenge, Atari were forced to accede to Nintendo's demands, leaving them with an estimated one hundred thousand unsold and now worthless game cartridges. Although the legal wrangling between Atari and Nintendo would continue for some time, Nintendo (and Bullet Proof Software) would ultimately be triumphant. Several million copies of Nintendo's version of Tetris were sold for the Nintendo Entertainment System, while the handheld version of Tetris bundled with the Gameboy helped Nintendo to achieve sales of over thirty million Gameboy units.

While all of this was going on the man behind Tetris, Alexéy Pájitnov, had received no financial reward for his efforts, even though the game had assured him a place in computer gaming history. He had, however, formed a lasting friendship with Henk Rogers. In 1991, Rogers helped him and his family to emigrate to the United States, where they found a new home in Seattle. In 1996, Pájitnov joined Microsoft as a games software developer. In the same year, the rights to Tetris reverted from the Russian state back to Pájitnov. With financial backing largely provided by Henk Rogers, Pájitnov and Rogers set up The Tetris Company. The name Tetris was registered as a trademark in the US (and most other countries in the world) through Pájitnov and Rogers' new company. The company claimed to hold the copyright for all products bearing the Tetris name in the United States. Pájitnov finally began to earn royalties for his creation, and had taken back a measure of control.

Today, Tetris can be found on every conceivable computing platform. It is estimated, for example, that some ten percent of all games sold for mobile phones in the United States are some variant of Tetris. Almost everyone you meet will have played some version of Tetris at least once in their life. Playing Tetris has been shown to have a positive effect on cognitive processes, and has even been suggested as a possible form of therapy for psychiatric conditions such as post-traumatic stress disorder (PTSD). The Tetris Company itself is currently striving to make greater inroads into the online gaming market, and has taken steps to protect its interests in that area by threatening, and in some cases implementing, legal action against online entities that it deems guilty of copyright or trademark infringement. The company set up a website, www.tetrisfriends.com, in an attempt to create an online community of Tetris players and promote competitive online social gaming centred around a number of Tetris game variants. This now seems to have morphed into a slightly more commercial entity (http://www.tetris.com)

_{This article was first published on the TechnologyUK.net website in January 2009.}

King's Quest - 1984

The story of King's Quest is not just the story of a computer game. It is the story of a software company (Sierra On-line) founded by Ken and Roberta Williams. The couple married in 1972, and originally lived in Los Angeles. Ken was nineteen years old, and his bride Roberta was even younger at the age of eighteen. Despite being a computer programmer, Ken found it necessary to take on freelance work in addition to his full-time job to support his wife and family (the couple's first son, D.J., was born in 1973). Roberta did her part to bolster the family finances, working as a computer operator. In 1979, Ken left his full time job to start his own software company, Online Systems. He was reportedly working on a taxation program for a customer's mainframe computer system when he came across a copy of William Crowther's 1976 single-player computer role-playing game Colossal Cave Adventure. He borrowed a computer terminal, and took the game home to show Roberta. His wife had a passion for fairy tales and stories of all kinds, and he thought (rightly as it turned out) that she would find the game interesting.

Both Ken and Roberta became fans of Crowther's game, although Roberta was perhaps the more enthusiastic of the two. She subsequently tried to find other computer adventure games to play, without success. Undaunted, she decided to write her own game. Her first foray into game creation was called Mystery House, and was based on the work of crime writer Agatha Christie. The game's main character finds themself locked inside an old and apparently abandoned Victorian mansion with a number of other characters, who (probably somewhat predictably) begin falling victim to an unknown murderer. The player's character must identify the murderer before they themselves become a victim. Although Roberta had come up with the story for the game, she felt that it would be more engaging for the player if the game had a graphical element rather than just being text-based. With that in mind she produced some preliminary sketches. She realised, however, that she would not be able to write the game's program code herself. She knew she had to somehow persuade Ken to get involved.

Ken meanwhile had discovered the joys of the Apple II personal computer whilst working on software projects with his brother, and had acquired one himself. The first games produced by Ken and Roberta Williams would therefore be targeted primarily at the Apple II personal computer. Ken would subsequently spend several months writing the program code for Mystery House, but the real challenge lay in translating Roberta's ideas for the game's graphics into images that could be generated by the computer. There were no commercially available graphic drawing programs around at the time. The solution, or at least part of the solution, came in the form of the Versawriter, an innovative piece of hardware manufactured by Versa Computing of Newbury Park, California.

The Versawriter essentially consisted of a flat plastic bed, approximately thirty-six centimetres long by thirty centimeters wide, on which the user could place drawings. The drawing was then covered with a transparent plastic overlay. Attached to the bed of the device was a jointed arm with an electronic position sensor at one end of it. The sensor could be moved freely over the drawing outline, enabling the user to produce a digitized version of their drawing. The software provided with the device allowed the user to perform a number of useful tasks, such as changing the background and foreground colours, filling in enclosed areas of the drawing with a solid colour, rescaling the drawing, creating shaded areas, and even adding text. In short, it included many of the basic features to be found in a modern computer graphics software package. The functionality provided was certainly sufficient to fulfill the Williams' requirements, and came at a price (a few hundred dollars) that they could afford.

The graphics for mystery house were not overly ambitious, consisting of static two-dimensional monochrome line drawings. Images were drawn with a white foreground colour on a black background, and were stored as vector graphics rather than bitmapped images. Additional information about each scene was provided using on-screen text. The player was still required to enter simple text commands in order to interact with the game, in the same manner as for purely text-based computer role-playing games. The real innovation in terms of programming was the code written by Ken Williams, which had to provide the game's underlying logic and render the game's graphics. The lessons learned in creating the software for Mystery House would later lead to the development by Sierra On-Line (as they would become known) of a series of increasingly sophisticated game engines.

Mystery House was completed in 1980, and the Williams placed an advertisement for the game in the personal computer oriented publication Micro Magazine. The game sold for just under twenty-five dollars, and was packaged in a Ziploc bag containing a five-and-a-quarter inch floppy disk and a printed instruction sheet. Copies of the game were available in software stores throughout the Los Angeles County area, and this first Online Systems game is estimated to have achieved sales of approximately ten thousand copies. Encouraged by their success, Ken and Roberta Williams announced that this was just the first of a series of games for the Apple II personal computer, for which they chose the name Hi-Res Adventures.

For the next game in the series, Roberta chose a very different theme. The game was called Wizard and the Princess, and the game's story, set in the imaginary kingdom of Serenia, reflected her lifelong love of fairy tales. The format of the game was otherwise identical to that of Mystery House, with players required to enter simple text commands. The major innovation was the use of colour, despite the fact that the Apple II could only display six colours. The user could be fooled into thinking that far more colours were present on the screen thanks to the use of a process known as dithering, in which adjacent pixels are displayed using two different colours to create the impression of a third colour. The new game was released later in the same year as Mystery House (1980), and like its predecessor was packaged in a Ziploc bag containing a five-and-a-quarter inch floppy disk and a printed instruction sheet. Wizard and the Princess was even more successful than Mystery House, and reportedly sold around sixty thousand copies.

The financial success of their first two games was such that Ken and Roberta Williams, who had meanwhile been blessed with a second son, Christopher, were able to fulfill their ambition of moving out of Los Angeles and into the home of their dreams in Oakhurst, California, not far from Yosemite National Park. They also opened their first official offices in Oakhurst, but changed the name of the company to Sierra On-Line following the discovery that the name Online Systems was already being used by another company. By the end of 1983, six games had been produced in the Hi-Res Adventure series, culminating in The Dark Crystal, based on Jim Henson's animated fantasy film of the same name, and produced in collaboration with Jim Henson. In terms of gameplay, the games all followed more or less the same format. The Hi-Res Adventure series was so successful that Sierra had to recruit additional staff to cover the increased workload. Perhaps just as significantly, Sierra was beginning to attract the attention of major players in the computer industry.

Obviously aware of the emergence of a diverse range of personal computing platforms, Ken Williams had foreseen the need to adapt the games, which were initially written for the Apple II, so that they could be ported to other popular personal computers. Target platforms included the IBM Personal Computer, the Atari ST, and the Commodore 64. IBM were meanwhile developing their PCjr personal computer, which was intended primarily for home and educational use. They approached Sierra On-Line to develop a game to help to show off the hardware capabilities of their new computer, which boasted one hundred and twenty-eight kilobytes (128 kB) of memory, a graphics chip that offered six display modes and could display up to sixteen different colours simultaneously, and a programmable sound generator chip developed by Texas Instruments that included three separate tone generators. The game put forward by Sierra On-Line for the PCjr was Roberta Williams' most ambitious project to date - King's Quest.

The screenshot above shows the opening screen of the 1987 version of King's Quest, which has a screen resolution of 640 x 400 pixels. Incredible as it may sound given the high screen resolutions available today, the version initially created for the IBM PCjr used the computer's 320 x 200 pixel EGA (Enhanced Graphics Adapter) mode. Realising that the program code used for the HI-Res Adventure series of games would not be up to the task, Sierra's programmers created a new game engine for King's Quest, which they named the Adventure Game Interpreter (AGI). The AGI game engine controlled the game's logic, rendered the game's graphics, and played the game's sound. Although initially designed around the hardware capabilities of the PCjr, it was also designed to be platform independent. This turned out to be a sound strategy on the part of Sierra On-Line. IBM's PCjr personal computer turned out to be a commercial failure, mainly due to its high price tag (by comparison with other personal computers of the day) and poorly designed keyboard.

An interesting technical issue arises here, since I have stated above that the game ran on the IBM PCjr at a resolution of 320 x 200 pixels. This would certainly have been the most appropriate resolution given the IBM PCjr's hardware specification, but all the documentation I have come across so far suggests that Sierra's AGI game engine was based on a resolution of 160 x 200 pixels. There is no doubt in my mind however, having viewed video footage of the game actually running on an IBM PCjr, that the resolution being displayed must be 320 x 200 pixels. The anomaly can be explained if you assume (since the game engine produces vector graphics rather than bitmapped images) that all of the screen coordinates have their x-values increased by a factor of two before the images are displayed. If anyone knows differently, maybe they could email me. At any rate, since vector graphics can cause considerable screen flicker when drawn directly to the screen (especially on slower hardware) the image vector information is used to create a bitmapped image which is temporarily stored in a memory buffer. The resulting bitmap is then copied into the screen display memory, and the completed image is displayed on the screen without flicker. This process is known as a bit-block transfer (sometimes called a "bit blit").

This first game in the King's Quest series has a similar theme to Wizard and the Princess, although it is far more ambitious in its scope. It takes its inspiration from the fairytales and other stories that Roberta so enjoyed. The game's story is set in the kingdom of Daventry, which is ruled over by King Edward the Benevolent. The kingdom's fortunes are somewhat dependent upon three artifacts that are invested with special powers - a magic mirror that can be used to foretell the future, a shield that protects the wearer from harm, and a treasure chest that contains an inexhaustible supply of gold. These artifacts have been used in various ways to maintain the security and continued prosperity of the kingdom. At the time the story begins, however, the three items are no longer in the possession of the royal family of Daventry. An evil sorcerer has obtained the magic mirror, a mysterious dwarf has gained possession of the shield, and a wicked witch has stolen the treasure chest.

To compound matters, Edward's queen has died, leaving him without an heir. Bereft of its treasures, the kingdom has suffered a steep decline in its fortunes, and is vulnerable to attack from hostile neighbouring lands. In desperation, King Edward summons the bravest knight in his realm, Sir Graham, and promises him the throne if he can retrieve the kingdom's three treasures. It's not going to be easy though. As you can see from the screenshot below, there is a real possibility of Sir Graham meeting an untimely death before he has even arrived at the castle to answer the King's summons! Of course, the presence of alligators in what otherwise looks like a typical medieval castle moat, possibly somewhere in Ye Olde England (or at least Europe) stretches the imagination somewhat, but it sets the scene for the kind of thing you can expect throughout the game, and indeed throughout the entire series of King's Quest games.

The screenshot above serves to illustrate the graphic nature of the game. The game world and its characters are depicted in a third-person perspective, and although the graphics are still very much two-dimensional, a partial three-dimensional quality is added due to the fact that the character can move over, under, behind, or in front of objects or other characters. Note that text commands (entered at the prompt at the bottom of the screen) are still used to undertake specific actions, but Sir Graham's movements around the game world are controlled by the player using the keyboard's left, right, up, and down arrow keys. The other really exciting thing at the time the game was released was the fact that that both the characters and many of the objects in the game world were animated. Although the game Dragon's Lair had featured high-quality animation, player interaction was essentially limited to choosing between different cut scenes at pre-defined points in the game. In King's quest, the player has total control of the main character's movements and actions using a combination of keystrokes and text commands.

You will notice that, as you approach the boundary of a particular scene, you will automatically move into the nearest adjacent scene. The game is in fact designed as an eight-by-six grid (imagine something like a Chess board with six rows of eight squares), with forty-eight separate scenes. There are also a further thirty-two scenes, accessible from the main grid, used to depict the inside of caves, buildings, and other types of environment. The game world is designed to wrap around on itself so that if (for example) you move Sir Graham far enough to the north, he will end up at the southernmost boundary of the game world. As you progress through the game, you will be awarded points for various actions taken, tasks completed or puzzles solved. The points are displayed at the top of the screen, on the left-hand side. In all, one hundred and fifty-eight points are available, although you do not need to get all of the points to complete the game. You will also be able to collect various artifacts as you progress through the game, at least some of which will be required at some later stage in order to retrieve the various treasures and return to the court of King Edward in one piece.

In the later stages of the game, you will be required to solve a number of puzzles. As well as the various artifacts that you can collect throughout the game (some of which are more useful than others), you will also come across snippets of information or hints that will help you solve the puzzles that you are presented with later in the game. The information presented to you may not immediately make sense, but it is worth remembering, since there is a good chance that a context will arise in which it does make sense. If your memory is anything like mine, you would be well advised to write any such information down on a piece of paper.

The puzzles that must be solved in the game often involve doing the right thing in a given situation, but they often also depend on having a suitable artifact to hand when the time comes. Roberta Williams usually designed her puzzles so that there were two possible solutions, one of which would require more thought (or at least a more subtle approach) than the other. The more sophisticated solution invariably earns the player additional points. In order to retrieve the magic mirror, for example, Sir Graham must confront a dragon in its underground lair. Sir Graham has in his possession (at least if he has been diligent in acquiring the various artifacts available throughout the game) a dagger. Having entered the dragon's cave through a well, he may also have in his possession a bucket filled with water. Throwing the dagger at the dragon will (believe it or not) kill the dragon, leaving Sir Graham free to retrieve the magic mirror. On the other hand, throwing the water over the dragon will extinguish the dragon's fiery breath, rendering it relatively harmless and preventing the need to actually kill it.

In reality, unless you do what I did and cheat (!!), you will probably meet an untimely death on more than a few occasions before overcoming all the obstacles and solving all the puzzles in the game, let alone figuring out the optimum solution to each puzzle. Because time is always an issue for me, I used one of several available online walk-throughs (step-by-step instructions on how to tackle the various tasks) in order to complete the game. The secret with this game, as with many others, is to save your game after each milestone achieved, so that in the highly likely event of your death (upon which Sierra offer their most sincere condolences), you can resume the game without having to go right back to the start. All in all, the game is quite a challenge, and can take a considerable amount of time to complete if you don't resort to seeking outside help. But then, that's the whole point of a game, isn't it?

One of the most difficult puzzles to solve comes near the end of the game, where you are confronted by a "crotchety old gnome". When you approach the gnome and speak to him, he tells you that he can give you something of value providing you can correctly guess his name. Those of you who are as familiar with German fairy tales as Roberta Williams obviously was may surmise that the name of the gnome is "Rumplestiltskin". This, however, is not quite the answer that is required here. Whilst pondering the solution to the puzzle, you may remember a hint that you memorised earlier in the game (or, as in my case, refer to something you wrote down on a piece of paper at the time). The advice takes the form of a note (as depicted in one of the screenshots above) that says "Sometimes it is wise to think backwards". So you nod wisely to yourself and type in the name "Nikstlitselprum".

Unfortunately, this doesn't seem to work either. Oh dear, it could take a very long time to finish the game! The answer, in fact, is to take the letters of the name you (probably) first thought of - Rumplestiltskin - and work out the position within the alphabet of each letter. You then need to reverse the order of the letters of the alphabet, and take the letter corresponding to the original position for each letter of the new name. Roberta Williams was obviously a very devious lady. Anyway, the result you should come up with is "Ifnkovhgroghprm". Once you have correctly worked out the name of the crotchety old gnome, he will give you some magic beans which will no doubt come in handy for something (magic beans on toast, for example). Actually, as you may have already guessed, the beans will be used to grow a giant beanstalk. Hmm . . . where have I heard that before?

Climbing the beanstalk proves to be a lot harder than it at first appears, so you would be well advised to save your game before you start this endeavor. Actually, you will probably need to save your game at various stages on the way up the beanstalk as well. A single false move at any one of several points on the climb will see Sir Graham plunge to an untimely demise. Once you manage to climb the beanstalk, you find yourself at the top of a mountain where a giant lives (no surprise there, then). It's not the only way to get up there, and certainly not the easiest, but it is the most advantageous from the point of view of earning points. The giant has in his possession the missing treasure chest, which you must of course obtain. As with the fire breathing dragon, there are two alternative courses of action. If you have found the sling (hidden somewhere on the mountain in a hole in a tree), you can simply kill the giant with it and steal the chest. Alternatively (and worth more points) you can simply avoid him until he falls asleep, and then steal the chest. If you acquired the magic ring from the elf earlier in the game, you can use it here to make yourself invisible.

Once you have found all three of the treasures that belong to the Kingdom of Daventry, you can return to the castle of King Edward and claim the throne. The order in which you retrieve the treasures is not particularly important, but it makes life much easier if you have the appropriate artifacts in your possession before you encounter a situation in which they can be used to advantage. If not, you may find yourself backtracking in order to obtain the required item. Of course, this is easier said than done, and hindsight is indeed a wonderful thing. Note that even after you have obtained all three treasures, you can still lose them (look out for thieving dwarves, sorcerers and the like) and you can still die if (for example) you wander into the raging river, or even the castle moat (the alligators are still there). Sadly, your triumphant return will also lead to King Edward having a heart attack, but that's life, I suppose.

King's Quest was released in 1984, timed to coincide with the release of the IBM PCjr. Although the PCjr suffered from much poorer than expected sales and was cancelled the following year, Sierra had been prudent in retaining all rights to the game. They subsequently produced ports for many other popular personal computing platforms. Notable among these was the version produced for the Tandy 1000, which was also released in 1984. The new Tandy computer, unlike IBM's ill-fated PCjr, was a commercial success. It was also compatible with the IBM PC, and boasted a similar hardware capability in terms of graphics, audio, processing power and memory, to the PCjr. King's Quest thus reached a large and appreciative audience, despite the failure to launch of the PCjr.

King's Quest spawned seven sequels in total. The first of these is King's Quest II: Romancing the Throne, which was released in 1985. Graham is now King of Daventry and the land is prospering. Despite being loved by his subjects, however, Graham is lonely. He has no queen, and hence no prospect of an heir to the throne. Then one day, looking into the magic mirror, he sees a vision of a quartz tower that can only be accessed via a magic door located in the nearby land of Kolmya. It is subsequently revealed to Graham that a beautiful girl is imprisoned in the tower. Realising that this must be his future bride, Graham sets off to rescue her from the quartz tower. During this adventure, Graham will encounter several literary and mythological characters, including Little Red Riding Hood, Count Dracula, and King Neptune.

Needless to say, Graham will ultimately be successful in his quest to rescue the fair maiden (her name is Valanice), who of course will then become his queen. Although this second installment in the King's Quest series features a totally different landscape and completely new scenes, the gameplay is more or less identical to that of the first game. One significant difference is that the landscape no longer loops around on itself when the player moves continuously in an easterly or westerly direction. Instead, natural barriers present themselves in the form of the sea to the west, and mountains to the east. Looping still takes place from north to south, however, and vice versa. The version originally released for the IBM PC came on two five-and-a-quarter inch floppy disks or one three-and-a-half inch floppy disk.

In 1986, Sierra released the third installment in the King's Quest series, King's Quest III: To Heir is Human. Like its predecessor, King's Quest III is not set in Daventry. Fans of the series were unperturbed by the change of scenery, but were initially somewhat put out by the fact that King Graham is no longer the main character. In the opening screens of the game we are introduced to the game's protagonist, a seventeen year old boy called Gwydion. For as long as he can remember, Gwydion has lived with a cruel and evil wizard called Manannan. Treated like a slave and forbidden to leave the Wizard's house, Gwydion has no idea of how he came to be in the situation in which he finds himself. The game's manual tells us that Manannan kidnaps a one year old boy every seventeen years to be his slave. The fate of each boy is already sealed, since Manannan will not allow them to grow to manhood. Fearing that an adult slave will become too bold or inquisitive to be easily controlled, Manannan kills each boy on his eighteenth birthday.

Gwydion must take advantage of the wizard's frequent but all too brief absences in order to find or steal the ingredients for various magic spells that he can eventually use to render the wizard harmless and escape. The spells themselves can only be found in the game's manual - a subtle form of copy protection. If caught in the act of stealing, or discovered to be somewhere he shouldn't be, Gwydion will be killed by the wizard. He must hide any items he obtains under his bed (where, apparently, they can't be seen by the wizard) until such time as they can be used to his advantage. The player is very much working against the clock in this game, and only has a short time in which to find and acquire the items they will need in order to cast the various spells. Some of these items can be found in Manannan's secret workshop in the cellar, while others reside in a number of different locations in the countryside surrounding Manannan's mountaintop retreat.

From time to time during the game, Manannan will either make a short journey or take a nap. Each time Manannan is absent, Gwydion has twenty-five minutes (in real time) to find ingredients for spells and perform the necessary rituals. The rituals can only be performed in Manannan's workshop, and must be carried out exactly in accordance with the instructions in the spell book (i.e. the game's manual). If a mistake is made, the results will be catastrophic for Gwydion. As with previous games in the series, any misstep during the game is likely to be fatal, so the player is well advised to save their game after making significant progress. They can then restore the game in the event of Gwydion meeting an untimely end. Before Manannan returns from a trip or awakens from a nap, Gwydion must hide both his possessions and any evidence of having been in Manannan's workshop. In the event of Manannan returning from a trip, he will demand food. Gwydion must therefore ensure that he has something for Manannan to eat. For obvious reasons, food items that are required for spells should not be used.

If Gwydion forgets to cover his tracks, or is discovered in possession of items that can be used for magic spells (which would reveal that he has been to places he is not permitted to go), Manannan will literally "zap" him out of existence and the game is over. The inventory command can be used to check whether Gwydion is currently carrying any possessions, and if so whether any of those possessions will get him into trouble (all such items in the inventory list are marked with an asterisk). From time to time, Gwydion will come across bandits and other characters on his travels that will steal his possessions if they get the chance. The best way to deal with this problem is to avoid these characters altogether. Failing that, in the event of Gwydion losing his possessions due to theft, a previously saved game can be restored. Since the appearance of characters with a predisposition to theft is usually purely random, Gwydion is unlikely to encounter this problem every time they enter a particular scene.

At some point in the game Gwydion will be told by an oracle that he is actually Alexander, a prince of the royal house of Daventry, kidnapped by Manannan as an infant. He is also informed that Daventry is being terrorised by a monstrous three-headed dragon that periodically demands the sacrifice of a fair maiden. He is also told that (purely by coincidence, of course!) the dragon's next victim will be Alexander's twin sister, Rosella. Once Gwydion has managed to dispose of Manannan (either by turning him into a cat or poisoning him) he must attempt to return to Daventry to save his sister from becoming the dragon's next meal. This will involve a sea voyage, courtesy of some not particularly friendly pirates, and an encounter with the Abominable Snowman.

Once Alexander has arrived in Daventry he is greeted by an old gnome, who has apparently been expecting him. The gnome tells him that time is running out for Rosella, and that he must make haste to confront the dragon and rescue his sister. The dragon can be defeated, but only by using two of the magic spells acquired from Manannan's spell book. Alexander must first make himself invisible so that the dragon will not incinerate him on sight, and then conjure up a storm that will strike the dragon with lightning bolts and kill it. Our hero has, in fact, had to use magic frequently throughout the game in order to escape Manannan and other hostile entities. Indeed, one of the items that Gwydion/Alexander must use in his quest is a magic map that he steals from Manannan. At certain points in the game, the map enables him to instantly teleport to almost any location he has already visited.

The map feature was reportedly frowned upon by some King's Quest fans because they thought it made the game too easy to play. In any event, it did not appear in later games in the King's Quest series. The game was released on three five-and-a-quarter inch floppy disks or two three-and-a-half inch floppy disks. Tweaks to the Adventure Game Interpreter (AGI) had provided improvements in the quality of both graphics and sound, which prompted a remake of the original King's Quest game in 1987. The remake included support for a sound card, VGA graphics, and a mouse. Nevertheless, the AGI was showing its age. The next game in the series, King's Quest IV: The Perils of Rosella, would be the last appearance for the AGI. The new game would also (as the title clearly suggests) feature Princess Rosella as the game's main character. At this point in our story, the King's Quest series of games had already earned its place in gaming history. The fan base was growing rapidly, and Sierra On-Line's fortunes were going from strength to strength. We will pick up the story again in a separate article, starting with the release of King's Quest IV in 1988.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Dragon's Lair - 1983

Dragon's Lair was developed by video game company Advanced Microcomputer Systems (later renamed RDI Video Systems) and published by Cinematronics. It was one of the first arcade games to make use of LaserDisc technology. The LaserDisc was the first commercial optical storage medium, and was much bigger than a modern CD-ROM or DVD-ROM disc. It was a revolutionary game in the sense that it utilised full motion video (FMV) sequences to provide the game's animated graphics. This was a complete departure from other video games of the time, which used either vector graphics or (more commonly) bitmapped graphics, the quality of which was constrained by the limitations of conventional storage media. However, the high quality graphics (which were admittedly stunning) came at the expense of gameplay. Indeed, the game was essentially an interactive animated movie, in which the player was restricted to controlling which animated cutscene would play next (a cutscene is a video sequence over which the player has no direct control). Nevertheless, when it first appeared in arcades in 1983, Dragon's Lair proved to be tremendously popular.

The arcade game version features an "attract mode" that cycles through a series of scenes from the game. While these scenes are playing, background music and a narrative describing the adventures awaiting the player within can be heard. In the game itself, the player must control the actions of a cartoon knight called Dirk the Daring, whose task is to enter the castle of an evil wizard, survive a number of potentially deadly encounters with various hazards and hostile creatures (including, of course, the dragon of the game's title), and rescue the beautiful Princess Daphne. Dirk is portrayed as a heroic but somewhat comically inept character, who nevertheless (if the player makes all the right moves) is able to survive everything the castle throws at him and rescue the fair maiden. Daphne herself is portrayed as a beautiful but stereotypically airheaded (and somewhat scantily clad) blonde, a characterisation that would inevitably draw criticism. The game has on occasion been accused of being both violent and sexist.

The original concept for the game came from Rick Dyer, president of Advanced Microcomputer Systems. Dyer was apparently a huge fan of William Crowther's text-based adventure game Colossal Cave Adventure, which has also been the inspiration for other computer games including the original MUD. He is reported to have also taken inspiration from the works of author J.R.R. Tolkien (primarily Lord of the Rings), and the 1982 animated film The Secret of Nimh, which was directed by Don Bluth and based on a children's novel written by Robert C. O'Brien. Dyer had already been working for some years on another LaserDisc-based game called The Secrets of the Lost Woods, which featured mostly static images for each scene, accompanied by a spoken narrative. He soon realised, however, that in order to capture the imaginations of a new generation of gamers, he would have to include animation. The central theme of Dragon's Lair was taken from a scene of the same name originally intended for inclusion in Secrets of the Lost Woods.

Dyer realised that the quality of the animation could well determine whether or not the game was a success. Consequently, Dyer and Jim Pearce (president of Cinematronics) sought out the services of Don Bluth. Prior to his work on The Secret of Nimh and other animated films, Bluth had worked as a Disney animator. He parted company with Disney in 1979 to set up his own animation studio, Don Bluth Productions. Bluth was presented with a set of storyboards created by the AMS game designers that detailed the various characters and scenarios for the game, but he and his team of animators (most if not all of whom were ex-Disney personnel) were given a relatively free hand. There were of course some constraints, as both the budget and the development timeframe were limited. The game reportedly took approximately seven months to develop, with the cost being estimated at a little over one million U.S. dollars. A company called Starcom was set up specifically for the venture, with Rick Dyer, Don Bluth Productions and Cinematronics each holding a one-third share in the new company.

The need to cut costs wherever possible meant that the animators did the voiceovers for the characters themselves, although the narration for the so-called attract sequence was done by a professional voice actor, Michael Rye. Princess Daphne's voice belonged to Vera Lanpher, who was in charge of the "Clean-up" department (the department responsible for producing "clean" versions of rough animation drawings). Dirk the Daring's voice was that of film editor Dan Molina. Not that there is an awful lot of dialogue - Dirk makes some fairly comical noises when confronted with various situations, but the only words he utters are "Uh, oh" (in one particular sequence, when the platform he is standing on begins to disappear) and "Wow!" when seeing Daphne for the first time. The character of Daphne was apparently based on pictures of a number of girls featured in Playboy magazine. Not that I would know anything about that particular publication . . . .

. . . anyway, the developers (including Don Bluth and his team of animators) were working under quite a bit of time pressure, and everyone was sworn to secrecy since "industrial espionage" was not uncommon in the gaming industry at the time. The game featured some original music, most of which could be heard in the attract mode. The synthesized soundtrack material was created by Chris Stone at EFX Systems in Burbank, California. EFX Systems were employed as outside contractors, and were not part of the development team as such. The final result was a game that included approximately twenty-two minutes of high-quality video animation and an original audio soundtrack. Both the video sequences and the soundtrack for the game were stored on a high-capacity LaserDisc, and the arcade cabinets incorporated LaserDisc players supplied by Pioneer Corporation (Pioneer is a multinational consumer electronics company based in Japan).

Like other arcade games of the period, the game's code ran on a Zilog Z80 microprocessor mounted on a proprietary motherboard. The game's hardware was housed in an upright cabinet fitted with a CRT colour monitor. An LED display mounted above the main screen could be used to display the player's score, the number of lives left, and the remaining credit. The controls consisted of an eight-way joystick which was used to control the movements of Dirk the Daring, and a single button which was used to control his use of the sword. And of course, there was the all-important LaserDisc player.

The inclusion of LaserDisc technology inevitably pushed up the cost of the cabinets. In fact, each arcade unit cost almost twice as much as a typical arcade unit for any other game of the time. Cinematronics justified the cost to potential customers by pointing out that the units could be used to accomodate future LaserDisc games (such as the companion game to Dragon's Lair, Space Ace) without requiring significant modification. Arcade owners were also somewhat dubious about the proposed cost-per-play for the game. At fifty cents, Dragon's Lair cost twice as much to play as most other arcade games of its day. In the early 1980s, most arcade games in the US were designed to relieve the player of a quarter in exchange for a single play (a quarter is a twenty-five cent coin). Nevertheless, the game proved to be hugely popular thanks largely to the sheer quality of its graphics, the likes of which had never before been seen in an arcade game. Long queues could be seen at any location in which a Dragon's Lair arcade game unit was installed.

Of course there were criticisms. As mentioned previously, the superb graphics were only possible thanks to the use of animated video sequences, which greatly restricted the extent to which the player could actually control events. A major complaint from seasoned gamers was that, once the correct sequence of control inputs had been learned for getting through each scene, the game presented no further challenges. There was also no particular incentive to achieve a high score (although points awarded were displayed above the screen), since once the game had been completed, that was it. There were no higher levels. Some players new to gaming, on the other hand, found the game difficult or impossible to play. The lack of visual cues (or any other clues for that matter) meant that inexperienced players were more likely to witness Dirk the Daring's untimely demise multiple times than to actually make progress in the game, let alone successfully complete it.

There were also technical annoyances for both players and operators. The LaserDisc hardware needed to switch between the various video sequences stored on the disc, depending on which commands the player had input via the joystick or button. This meant that there were often significant delays between scenes, during which nothing was happening on screen. For much the same reason, the LaserDisc players initially used for the game (which were originally designed to play LaserDisc movies in a linear fashion) were prone to failure after a relatively short period of use, typically a few hundred hours at best. This meant that operators frequently needed to replace the players. The situation was not helped by the fact that Pioneer could not produce the LaserDisc players anywhere near fast enough to meet demand, which in turn meant that Cinematronics could not keep up with the demand for game units. Despite the game's limitations, Dragon's Lair was at first immensely popular. It was hailed as a major breakthrough in gaming technology, and was seen by many as the saviour of the video gaming industry, which in 1983 was going through a recession.

Players of Dragon's Lair were meanwhile treated to stunning visuals never before seen in an arcade video game. The player must control the actions of Dirk the Daring as he encounters various dangers on his mission to seek out and rescue the beautiful Daphne. Control is by means of an eight-way joystick (used to control Dirk's movement left, right, up, down or in one of four diagonal directions) and a single button that controls Dirk's use of his sword. The player must essentially either move Dirk in the right direction, or trigger his use of the sword, at exactly the right time. Failure to make the right move at the right time results in Dirk's death, which is usually (though not always) depicted in graphic detail. Fortunately, the death sequences are just as entertaining as the sequences in which Dirk manages to escape his fate.

The mechanics of the game are actually very simple. If you move the joystick in the right direction at the right time, and press the button at the right time, you move onto the next interactive scene and the next challenge. If not, you move on to the corresponding death scene. As mentioned above, the death scenes themselves can be quite entertaining. So much so, in fact, that players encountering a new scene have been known to deliberately allow Dirk to be killed just to see how he will meet his untimely end. In some cases, the exact details of Dirk's demise are not actually shown, and all we see is Dirk's sword or helmet hitting the floor. In every case, the player will be treated to a short scene in which Dirk drops into view from above with arms folded and a disgusted look on his face, turns into a skeleton, and crumbles to the floor.

Dirk will encounter all manner of dangers on his way through the castle, including amorphous creatures with multitudes of long green tentacles, giant spiders, snakes, blazing infernos, raging torrents of water, collapsing floors and ceilings, and all manner of bizarre creatures - basically all the worst parts of the Bible (OK, I admit it - I stole that line from Michael Bay's movie "Armageddon"). Anyway, to cut a long story short, there are some forty or so different scenarios in the game that Dirk will encounter before he can rescue Daphne, and in just about every one of them someone or something is trying to kill him. In some scenes, even apparently inanimate objects are not to be trusted. Dirk's facial expressions and utterances on encountering each new menace are highly entertaining, but the player must stay alert in order to escape the various perils.

The order in which the scenes appear can vary, depending on the specific version of the game being played. The only exceptions are the initial scene and the final showdown in the dragon's lair of the title, although for some reason the initial scene used for the North American version is different to that of the European version. In the European arcade version (which was licensed to Atari), the scenes appear in the order in which they are stored on the LaserDisc. The first scene (in the European version) is the drawbridge scene where Dirk first enters the castle, which also features in the "attract mode" sequence. It has been estimated that, if the player makes all the right moves, the game can actually be completed in approximately twelve minutes. This sounds reasonable considering that there are some twenty-two minutes of video material in total, and that a significant proportion of that video material depicts various death scenes (each scenario Dirk encounters within the game has its own unique death scene).

In the final scene of the game, Dirk has reached the dragon's lair and discovers that Princess Daphne is being held prisoner inside a magic bubble guarded by a rather large (though apparently sleeping) dragon. The key to the magic bubble is on a chain around the dragon's neck. Dirk is told about the key by Daphne, who also mentions that the only way to kill the dragon is by striking him with a magic sword (which just happens to be embedded in a jewel stone within the dragon's lair). If successful, he will be able to retrieve the key and free Daphne. Of course, he has to get past the dragon before he can get to the jewel stone with the sword in it. Needless to say, if our hero does manage to slay the dragon and free Daphne, she will be eternally grateful . . .

Dragon's Lair did indeed bring a much-needed boost to the video game industry in 1983, although ultimately it was to be a bright spot in an otherwise gloomy picture rather than the start of a recovery. It created a brief demand for LaserDisc games, which of course included the companion game Space Ace and a sequel, Dragon's Lair II: Time Warp. In the nine months or so following its release, Dragon's Lair would generate over thirty million dollars in sales of arcade game units, and an even higher figure in arcade revenues. As with other popular arcade games of the period, Dragon's Lair spawned a vast range of merchandise. This was no doubt something the developers had firmly in the back of their minds when they created the game's characters. Even the monsters in the game are designed to appeal to children, and are more humorous than scary. Typical products included lunch boxes, board games, children's clothing, posters, trading cards, stickers, action figures - the list is almost endless.

Like other arcade games of the era, Dragon's Lair has been featured in various forms of popular media. A Dragon's Lair arcade game unit could be seen in episodes of the US sitcom Silver Spoons which first aired on NBC's network in 1982. During the same period, the game was also featured in the arcade game related US game show Starcade. More recently, the character of Dirk the Daring was featured in an episode of the animated comedy sketch TV series Robot Chicken, and one of the scenes from the game was parodied in an episode of the animated adult sitcom Family Guy. An animated TV series based on the game, and produced by Ruby-Spears Productions, aired on the ABC network between September 1984 and April 1985 for a total of thirteen thirty-minute episodes. In the TV series, the dragon (who had no specific name in the actual game) was called "Singe", and Daphne was wearing a long pink dress. Well, it was a children's show!

Don Bluth and his fellow animator and business partner Gary Goldman have reportedly been planning a feature film based on the game for some years, and have everything in place including a completed script. The project has unfortunately been postponed indefinitely due to the fact that the necessary financial backing has so far not been forthcoming. At the time of writing however, a documentary film examining the phenomenon of Dragon's Lair is rumoured to be in the pipeline for release towards the end of 2013, thirty years after the game's original release, and will reportedly feature a number of interviews with legendary animator Don Bluth. Dragon's Lair certainly deserves its place in gaming history. Despite the fact that the popularity of LaserDisc games was somewhat short lived, this was the game that opened the eyes of gamers and game developers alike to new possibilities, particularly in terms of gaming graphics. Perhaps for that reason, Dragon's Lair is one of only three arcade games (the others being Pong and Pac-Man) on permanent display at the Smithsonian Institution in Washington D.C.

In the intervening years, Dragon's Lair and its sequels, remakes and spin-offs have been ported to just about every home computer and console platform. Most of the versions released for home computers and game consoles during the 1980s and early 1990s could not even remotely match the quality of the graphics seen in the original arcade version of the game due to the severe limitations imposed by available secondary storage media (typically audio cassettes, game cartridges, or floppy diskettes). Instead, they were usually platform-style adaptations that featured standard two-dimensional computer graphics. Some home computer versions managed to get close to the gameplay and graphic quality of the original by using a combination of video compression techniques and multiple floppy discs. Even so, a number of scenes from the original game had to be omitted in order to reduce the amount of storage required. The advent of high-capacity optical media during the 1990s, together with the availability of affordable optical drives for home computers and consoles, was a key factor in improving the graphical quality of games produced for these platforms.

The rights to the original LaserDisc games Dragon's Lair, its companion game Space Ace, and the sequel Dragon's Lair II: Time Warp are currently owned by Canadian software publishing company Digital Leisure Inc. Since 1997, Digital Leisure have published versions of these games for various platforms, including both IBM PC compatible and Macintosh personal computers, the Sony PlayStation (PS2, PS3 and PSP), the Nintendo Wii and hand-held consoles (DSi, DS and 3DS), Microsoft's Xbox consoles, and more recently mobile devices such as smartphones and tablet computers. There are even releases that run on standard DVD and Blu-ray players, in which the game is controlled using the keypad on the player's remote control.

If you want to enjoy an authentic arcade game experience on your computer, Dragon's Lair, in its original arcade format, can be played using an arcade emulator such as DAPHNE, which can be downloaded free of charge from the DAPHNE website (http://www.daphne-emu.com). The emulator software allows you to play Dragon's Lair (and many other classic arcade games), and will automatically download the required files from the Internet. The only drawback is that (at least with the most recent version of DAPHNE) you are required to insert a genuine Digital Leisure DVD-ROM disc into your DVD drive in order to prove that you own a legitimate version of the game before you can actually play it. There may of course be a work-around available, but we are unable to determine whether this is the case at the current time.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Ultima - 1981

Ultima was the creation of Richard Garriott de Cayeux (usually referred to simply as Richard Garriott, which was his name up until he changed it in 2011). Garriott is a prominent British-American video game developer, who in recent years has achieved even greater celebrity as one of the first civilians to go into space as a tourist. He was born to American parents in Cambridge, England in 1961. Despite his British origins, Garriott grew up in Texas, USA where he developed a keen interest in programming computers. Much of his time in high school was reportedly spent creating fantasy role-playing computer games. In the summer of 1979, Garriott obtained employment in a ComputerLand store and encountered Apple computers for the first time. The experience inspired him to create the role-playing game Akalabeth: World of Doom, the code for which he wrote in Applesoft Basic. Although the game was not originally intended to be a commercial product, the store's proprietor persuaded him that it had commercial potential.

Although his attempts to package and market the game himself did not result in many sales, a copy found its way to the offices of the California Pacific Computer Company, a software development company that specialised in publishing games and other software for the Apple II computer. They made a deal with Garriott to publish the game, which subsequently sold somewhere in the order of thirty thousand copies. Encouraged by this success, and with the help of fellow student Ken W Arnold, he went on to develop the fantasy role-playing game Ultima for the Apple II computer during his freshman year at the University of Texas. Like its predecessor, the original version of Ultima was written in Applesoft Basic. In fact, a lot of Akalabeth's program code was re-used for Ultima. The new game was also published and distributed by California Pacific, but Garriott was allegedly unhappy that it was sold in Ziploc plastic bags. His involvement with California Pacific ended when they filed for bankruptcy, not long after the publication of Ultima. The follow-up game (Ultima II: The Revenge of the Enchantress) was published in 1982 by Sierra On-Line, who had agreed to distribute the game in a box.

Garriott's relationship with Sierra was not a particularly happy one, and was consequently somewhat short-lived. In 1983, Garriott severed his ties with Sierra, and with his brother Robert set up his own company, Origin Systems. The company was established for the purpose of publishing and distributing role-playing computer games, primarily those created by Garriott himself. In that same year, Origin Systems released the third and final installment of the original Ultima trilogy, Ultima III: Exodus. In a way, Ultima was a continuation of Akalabeth: World of Doom. It certainly introduced a number of innovative features that would find their way into future role playing games, but its debt to its predecessor is such that Akalabeth has on occasion been referred to as Ultima 0, implying that it is in fact the first installment in the Ultima series of RPGs. A brief look at the features of Richard Garriott's early masterpiece thus provides us with a backdrop against which his subsequent efforts can be viewed.

The themes encountered in Akalabeth: World of Doom reflect Garriott's interest in more traditional forms of the role-playing game, in particular Dungeons and Dragons which was created by Gary Gygax and Dave Arneson, and first published in 1974 by Tactical Studies Rules Inc. Garriott was also clearly influenced by the work of J.R.R. Tolkien, author of Lord of the Rings and The Hobbit. The main difference between Garriott's game and the Dungeons and Dragons game that in part inspired it was that his game was designed for a single player. The game is controlled by the computer program's code rather than by a human dungeon master. Nevertheless, the game retains a fantasy setting, and involves characters and creatures that will be familiar to fans of both Dungeons and Dragons and the books of J.R.R. Tolkien, including wizards, warriors and assorted monsters.

Akalabeth's graphical environment, although crude by today's standards, was at the time considered both advanced and innovative. The above-ground environment is represented as a two dimensional landscape seen from above, as you can see from the screenshot above. The main character is represented by a plus sign ("+"), which the player moves around the landscape using the keyboard. In the version we downloaded, the up, down, left and right direction keys are used for this purpose. Single boxes represent trees, while symmetrical collections of five boxes linked together represent 'adventure shops' in which you can buy supplies and weapons (or even a magic amulet), and view your current statistics. Mountain ranges are represented by a somewhat less symmetrical pattern of interconnected vertical, horizontal and diagonal lines. The castle of Lord British (from whom you receive the various quests that you must undertake in order to complete the game) consists of two much larger rectangles, one inside the other, with a large "X" in the inner rectangle.

Finding the castle of Lord British is in itself far from easy. Once found, however, the player's character may enter and be assigned a quest from Lord British himself, which they must complete successfully in order to advance in the game. The name "Lord British" was apparently Garriott's nickname in school, and derives from the fact that he was born in Britain and (presumably) retained a slightly British-sounding accent. The character of Lord British would remain a central character in the Ultima series of games that followed. The quests handed out by Lord British invariably involved journeying into a 'dungeon' in order to kill some kind of creature lurking therein. The following screenshot depicts a typical dialog between our hero and Lord British upon the entry of the former to the latter's castle.

Once the player enters a dungeon (represented on the two-dimensional landscape by an "X"), the perspective changes to a very basic wire-frame three-dimensional first person view. The player finds themselves in a maze of underground passages in which they may encounter thieves and a variety of hostile creatures, including giant rats and bats. Whilst in the dungeon the player may accumulate gold (this is found in chests that appear in various locations), and of course carry out their designated quest, if they get an opportunity to do so. Each time the player is attacked, however, there is the likelihood that their health (represented by 'hit points') will be reduced. If the number of hit points reduces to zero, the player's character will die. Another thing to look out for is that you don't run out of food, because you can also die of starvation. Food can be purchased in any of the adventure shops that are scattered about the landscape.

Many sources cite Richard Garriott's Akalabeth as the first commercial graphical computer role playing game. It was certainly an important step in the evolution of the genre, and introduced features that would be copied by many of the computer-based role playing games that followed. The action is set against a background story in which Lord British, ruler of the kingdom of Akalabeth, has recently driven the evil wizard Mondain from the land. Unfortunately, many creatures loyal to Mondain remain at large, and can be found in various subterranean dungeons. The player's character accepts quests from Lord British in order to advance in rank from humble peasant to knight. The quests all involve descending into dungeons in order to seek out and destroy one of Mondain's creatures, and of course they become progressively more difficult. On first entering the game, the player has the choice of whether to play as a fighter or a mage. They can also select the level of difficulty, and make an initial purchase of food and weapons.

Many of the features first seen in Akalabeth are carried over into the Ultima series of games. Both the top-down view of the landscape and the wire-frame third person perspective of the dungeon environment are retained. Indeed, much of the code for Akalabeth was re-used for Ultima, as mentioned previously. The best-known version of Ultima is actually Ultima 1: The First Age of Darkness. This version was a re-write of the original, coded by Richard Garriott in assembly language and released in 1986. Garriott had obtained the rights to the original Ultima game from Sierra Online, and the new version was published and distributed by his own company, Origin Systems. The use of assembly language (rather than the Applesoft Basic used for the original program) made it much easier to port the game to different hardware platforms. Garriott also introduced a number of additional features and improvements, although the gameplay and background story remained unaltered.

In Ultima 1, the villain is once again the evil wizard Mondain. This time however, the world in which the action takes place is called Sosaria, and consists of four continents, each ruled by two lords. Lord British's Realm is ruled by Lord British (naturally) and the Lost King; the Lands of the Dark Unknown are ruled by Lord Olympus and the King of the Black Dragon; the Lands of Danger and Despair are ruled by Lord Shamino and the King of the White Dragon; and the Lands of the Feudal Lords are ruled by the lords of Castle Rondorin and Castle Brataria. Despite his defeat in Akalabeth: The First Age of Darkness, Mondain has returned with a vengeance and is now wreaking havoc once more, this time protected by the Gem of Immortality, which he apparently created some one thousand years in the past, and which makes him invincible. The player's character, known as "The Stranger", has apparently been summoned from another world (presumably Earth) in order to track down and destroy the Gem of Immortality so that Mondain's invincibility can be nullified. The Stranger must then defeat Mondain in combat.

At the start of the game, the player is invited to either create a new character or continue a previous game. Obviously, if this is the first time you have played the game you will choose to create a new character. The character creation screen gives you far more options than was previously the case with Akalabeth. The attributes for a character include strength, agility, stamina, charisma, wisdom and intelligence. Each attribute is automatically awarded ten points, with a further thirty points being available. The player may distribute the available points between the character's various attributes as they see fit. Obviously there is a trade-off to be made here. More points awarded to the strength attribute will mean more damage can be inflicted on an opponent in combat, but may mean that the character is less agile or has less stamina.

The next character creation screen allows the player to choose which race they want their character to be. The choices are between Human, Elf, Dwarf or Bobbit (a Bobbit is apparently a Hobbit-like creature). Depending on which race the player chooses for their character, the points allocated to each of the character's attributes may be adjusted to reflect the characteristics of that race. Elves, for example, are far more agile than Dwarves. Dwarves, on the other hand, are very strong. Further screens allow the player to choose the gender, name and class of their character. The name and gender do not affect the character's abilities in any way. The choice of class includes fighter, cleric, wizard or thief. The choice of class will also adjust the number of points that are awarded to each character attribute.

The background story is that the evil wizard Mondain has once more unleashed his hordes of malevolent creatures upon the world of Sosaria, and has used his magic to cause rifts between the various rulers of the land, rendering efforts to oppose him ineffective. Furthermore, he has attained virtual immortality thanks to his creation, some thousand years in the past, of the previously mentioned Gem of Immortality. The stranger has been informed that the only way to defeat Mondain is to travel back in time and destroy the gem before Mondain can complete it, and then meet Mondain in combat while he is still mortal. The stranger must therefore somehow find and activate a time machine which is hidden somewhere in the world of Sosaria. He can apparently achieve this only by completing eight quests, each of which is assigned by one of the eight rulers of Sosaria.

The reward for the successful completion of a quest takes the form of either a gem (there are four gems in total, all of a different colour) or the enhancement of some attribute vital to discovering the time machine's whereabouts and completing the game. The gems are required to activate the time machine. Quests usually involve killing a particular type of creature (which is invariably found in a dungeon) or visiting a particular place (which inevitably involves encountering a number of dangers). As the game progresses, the player will gain access to far more sophisticated forms of weaponry and transport. The various hoops that the player must jump through in order to complete the game include rescuing a princess from one of the eight castles (all of which apparently have a resident captive princess), and doing battle in outer space (in the style of Spacewars! or Asteroids).

Ultima introduced the concept of tile-based bitmapped graphics, which enabled the creation of large, colourful and relatively complex landscapes at a comparatively low cost in terms of computer memory. The game is controlled entirely using the computer's keyboard, with almost every letter of the alphabet being assigned a command. The up, down, left and right direction keys are used to move the player's character by one tile in one of the four cardinal directions (North, South, West and East) while the player is on the surface. In a dungeon, the up and down direction keys are used to move the player forwards or backwards, while the right and left direction keys rotate the player through ninety degrees clockwise or anti-clockwise. Examples of other keyboard commands include "A" for attack, "D" and "K" for descend and climb (to lower or higher levels of a dungeon respectively), "E" to enter a town or a castle (you need to be standing on the entrance at the time), and "T" to transact business with a merchant or a lord.

As in Akalabeth, it is possible (indeed necessary for survival) to purchase various items in the many towns that are scattered around the landscape (note that entering a town or a castle loads a separate two-dimensional screen). In order to do so, the player must accumulate money (referred to as coin). Coin, which may be copper, silver or gold, can be acquired by opening coffins in dungeons, or defeating enemies (either in dungeons or above ground). Engaging in combat with the creatures encountered in the dungeons earns the player experience points, which are required in order to progress to the higher levels. Food is essential to survival (without it the player's character will starve to death), as are hit points (which represent the character's health). The acquisition of better quality weapons will also improve the chances of survival. Food is consumed relatively quickly as the player moves through the above-ground landscape, but much more slowly as the player moves around in a dungeon. No food is consumed while the player is in a town or a castle. The player can also purchase various magic spells, which may be used once only.

The dungeons in Ultima looked more or less the same as the dungeons in Akalabeth (which is hardly surprising, since the same code was reused for this part of the game more or less unaltered). The code itself was full of bugs, which led to some interesting side effects on occasions. In fact, when Sierra Online released Ultima I for the Atari 8-bit computers in 1982, the version they released used the same program code as the original. The Atari release therefore not only reproduced the gameplay of the original, but the glitches as well. Richard Garriott's 1986 re-write of Ultima eliminated most, if not all, of the glitches. In the meantime, versions of the game had been released for a number of popular personal computer systems besides the Apple II and the Atari 8-bit family of personal computers, including the Commodore 64 and the IBM PC.

Origin Systems' 1986 version of Ultima, under its new name Ultima I: The First Age of Darkness, was released for a number of platforms, including the Atari 8-bit computers, the Apple II, the IBM PC and the Commodore 64. Like its predecessor, Origin's version of Ultima was released on a five-and-a-quarter inch (5.25") floppy disk. In addition, in keeping with what had already become a feature of Ultima games, the game was packaged in its own box and accompanied by a printed manual, maps of each of the four continents of Sosaria, a player reference card, and a cloth bag containing five Sosarian coins.

Ultima was the first in a long line of Ultima games. 1985 saw the fourth installment of the series, Ultima IV: Quest of the Avatar. The game included copy protection in the form of an unformatted track on the floppy disk. Pirated copies of the disk would apparently appear to function correctly, but the standard copying process could not duplicate the unformatted track. In the absence of the unformatted track, the player could never overcome an opponent in combat, and hence never progress in the game. In later versions of the game, the player was required to answer questions or translate scripts written in ancient runes in order to progress. The answers to the questions and the information required to translate the scripts could only be found in the game's manual. This feature was again no doubt intended, at least in part, to reduce the likelihood of piracy.

Perhaps more importantly there is a fundamental shift in emphasis, from Ultima IV onwards, away from simply killing monsters and completing quests and towards a narrative-driven approach. The world of Sosaria has been transformed geographically, and is now called Britannia. Lord British is now the sole ruler of Britannia. The player's character (whose ultimate goal in Ultima IV is to become an "Avatar") is faced with a number of ethical choices. The player can only become an Avatar by achieving enlightenment in the eight "virtues", which include honesty, compassion, valour, justice, honour, sacrifice, spirituality, and humility. Every significant action taken by the player's character is measured against the ideals embodied in the eight virtues, and will thus influence the player's progress towards becoming an Avatar.

In the first three installments of the Ultima series, the player could steal food, weapons or other items from shops, and even commit murder in order to progress in the game. The game reflected real life to some extent in the sense that such actions could have unfortunate consequences for the player if they were caught in the act by one of the guards. Later games in the series would develop this idea much further, to the point where every action would have a consequence, even if that consequence was not immediately obvious. Such innovations very much embodied Richard Garriott's ideas of what a role playing game should be. Although he sold Origin Systems to Electronic Arts (EA) in 1992 in order to fund his activities in the field of space exploration, he remained with the company and continued to influence the development of the Ultima series. Ultima VII: The Black Gate, released in 1992, would be the last game of the Ultima series published by Origin Systems as an independent company.

Ultima V: Warriors of Destiny was first released by Origin in 1988, and continues the story from where Ultima IV leaves off. The player's character ("The Avatar") must return once again to Britannia to rescue Lord British, who has been lost on an expedition to the Underworld, and who has been replaced as ruler by the tyrannical Lord Blackthorn. Blackthorn, under the influence of three evil and occult beings known as the Shadowlords, presides over a fundamentalist regime in which the eight "virtues" have been corrupted into a set of mandatory behaviours that are enforced through terror. The Avatar must find a way to defeat the Shadowlords, depose Blackwood, and restore the benevolent rule of Lord British. This game was the last in which a significant amount of program code was written by Richard Garriott, although he would continue to influence the design of future Ultima games.

1990 saw the release of Ultima VI: The False Prophet. In this game, Britannia has been invaded by demon-like creatures called Gargoyles. Here too, however, there is an ethical question to be resolved, as it emerges during the game that the Gargoyles have their own value system not unlike the virtues embraced by Britannia. Ultimately, the object of the game is to make this discovery and attempt to find a peaceful outcome. In technical terms, Ultima VI was a significant advance on previous installments of the Ultima story because it targeted the superior graphics capabilities of the new VGA graphics cards, which had first appeared on IBM PS/2 personal computers in 1987 and which were rapidly becoming standard equipment for the IBM PC. The game could also be set up to use a sound card to play music, and to receive input via a mouse.

Ultima VII: The Black Gate was released by Origin in 1992, and was acclaimed by both game pundits and Richard Garriott himself as the best game of the Ultima series. The game's graphics were significantly better than those of previous versions, and included the use of pop-up menus. Player input could be achieved solely using a mouse, including the facility to "drag and drop" items from one location to another. The game can of course still be played using the keyboard, but this is no longer the optimal method. The game also features a much higher level of built-in intelligence for controlling both the dialog generated by non-playing characters in response to player commands or actions, and the behavior of various characters in a combat situation. The level of interactivity is also greatly enhanced, with the player able to interact in some way with nearly every object in the virtual world. In addition, although there is still a definite storyline, the player is not constrained by it. They may explore the world and carry out tasks in a (more or less) random order.

The emphasis on behaving virtuously is dropped in Ultima VII, although any reprehensible actions may still have consequences. The Avatar is once again summoned to Britannia, apparently some two centuries after the events of the previous installment, to investigate a series of gruesome murders, the activities of a mysterious religious organisation called the Fellowship, and the nature of a new antagonist called the Guardian. Unlike earlier games in the series, Ultima IV was released in two parts, both of which could be expanded by means of purchasing additional software game packs.

The Electronic Arts era inevitably brought changes for the way in which the Ultima series would develop. Ultima VIII: Pagan, released in 1994, was seen by many as a departure from the role-playing nature of previous installments. More action oriented, It was nicknamed "jump and run Ultima" by fans of the series. Perhaps due to lack of development time, the game was also notorious for software glitches. The same kind of problems would affect the final game in the series produced by EA, Ultima: Ascension, released in 1999. As a result, many fans of the series became disaffected. Garriott himself had also reached the end of the road with EA. He parted company with them in 2000, taking his brother with him. Despite all the problems however, 1997 saw the emergence of the first large-scale multiplayer online role-playing game, Ultima Online.

It was in fact Richard Garriott who first used the term massively multiplayer online role playing game (MMORPG) to describe Ultima Online. Like other Ultima games produced by EA, Ultima Online had its fair share of problems. When the game first went live, it was hosted on a single server which promptly crashed when several tens of thousands of beta testers tried to access the game. Nevertheless, the game became hugely popular, and is possibly one of EA's most successful games to date. It has undoubtedly been a major influence in the development of other MMORPGs, such as World of Warcraft. At the time of writing, Ultima Online is still going strong and can be found at Origin's Ultima Online web portal (http://www.uo.com). The site allows you to set up a free trial account, should you wish to experience Ultima Online for yourself.

After his departure from EA, Richard Garriott continued his involvement with the computer gaming industry, setting up a new company called Destination Games in 2000. He hired back many of the former Origin Systems personnel who had meanwhile been laid off by EA. With limited funds, however, Garriott needed to find outside backing for his new venture. This came in the form of a partnership with the South Korean company NCSoft, who shortly after the release of Ultima Online had developed their own highly successful MMORPG, called Lineage, which had several million subscribers (mostly in in South Korea). Despite their success in Korea, NCSoft were virtually unknown in the US. A partnership with Destination Games was exactly what they needed to raise their profile there. Destination Games could also provide a number of highly experienced game developers. In return, they would receive the funding they needed. Destination Games duly became NCSoft Austin.

Richard Garriott held the position of CEO at NCSoft Austin, where (among other things) he oversaw the development of MMORPGs such as the innovative but ultimately ill-fated Tabula Rasa. In 2008, Garriott apparently published an open letter on the Tabula Rasa gaming website stating his intention to leave NCSoft in order to concentrate on other interests. He later filed a lawsuit against NCSoft on the grounds that he had been forced out, and that the letter had been forged as a means to facilitate his removal. Meanwhile he established a new company, Portalarium, in 2009. With Garriott at the helm, Portalarium developed and published games for the social media market until it was sold to Catnip Games in 2019. A "spiritual successor" to the Ultima series, Shroud of the Avatar: Forsaken Virtues, was initially planned for release in 2014, but the full version was not released until March 2018. According to a statement on Portalarium's website, Garriott has vowed to continue his lifelong quest to create the "Ultimate Role Playing Game".

_{This article was first published on the TechnologyUK.net website in January 2009.}

Frogger - 1981

Frogger was an arcade game developed by Japanese company Konami, a company that started out as a jukebox rental and repair business in 1969. Today they are one of the world's leading gaming companies, but in 1981 they had only been in the arcade game business for about three years. They had nevertheless already made an impact. Early in 1981 they produced Scramble, a shoot 'em up game in which the player controls a jet aircraft. The game was released in the USA under license by Stern Electronics Inc. They followed this up with Super Cobra, a similar type of game but this time featuring a helicopter gunship. Super Cobra was also released in the USA under license by Stern. Both games were well received. Konami were nevertheless no doubt aware of the emergence of games like Pac-Man and Donkey Kong, both hugely successful games having a much broader appeal than the average shoot 'em up.

Although Frogger was perhaps not as innovative as either Pac-Man or Donkey Kong, it was nevertheless an enormously playable and popular game, and is recognised as one of the all-time classic video arcade games. Like other successful games of the time, it was easy to play, difficult to master, and very addictive. It's also a game that is difficult to categorize. There is not much of a story line as such. The player controls a two-dimensional frog using a joystick. The game is played from a top down perspective, and the idea is to get the frog from the bottom of the screen to one of several predefined locations at the top of the screen, avoiding a number of hazards. The game has aspects that suggest an adventure game, but it is really about developing strategies to avoid the various pitfalls that lie in wait for the frog on its homeward journey. In that sense it's more of a puzzle game.

The original arcade version of Frogger was one of several arcade games to feature two microprocessors. The main processor was a Zilog Z80 running at 3.072 megahertz. This processor executed the game's program code. The second processor was also a Z80 chip, running at a slower 1.790 megahertz, which was used to control the game's sound. Frogger featured continuous background music and sound effects that varied in accordance with what was happening on the screen. The hardware also included additional dedicated sound chips. Like other arcade games of its time, Frogger could be found both in upright cabinets and in the cocktail table format. The arcade version of Frogger also featured a four-way Joystick, which was the only control required for actual gameplay.

The screenshot above is taken from a playable online version of Frogger, of which there are numerous examples to choose from. I chose this one simply because I liked the name "happyhopper". As you can see from the screenshot, our frog (one of several, in effect) starts the game at the bottom of the screen. In this part of the screen he is quite safe, but complacency is not an option here as you only have about sixty seconds to get him to one of the home locations at the top of the screen. There are five home locations, each represented by a lily pad (at least that's what they are supposed to look like) in its own small niche in the riverbank. The first obstacle that our small green amphibious hero has to contend with is the rather busy five-lane highway, which he must of course traverse to get home. Strangely, the traffic in alternate lanes goes in different directions, but maybe it's a new kind of traffic-calming scheme.

On the first level, it's not too difficult to get across the road. You can literally 'go with the flow' of traffic and wait for the gaps to appear. The frog will move one place to the left, right, up, or down each time the joystick is moved in one of these directions. For most web-based versions, the direction arrows are used instead of a joystick. The frog must avoid being hit by a moving vehicle or lose a life. Once the frog reaches the strip of land between the highway and the river, he is once more on safe ground (but remember that the clock is ticking). In the river you are once more faced with five lanes of moving objects. This time, however, you must use the objects to get the frog across the river without being drowned, hopping from one object to the next in order to get to one of the lily pads. In the first level, allof the objects are logs or turtles. The logs move from left to right across the screen, while the turtles move from right to left.

Just to make life more interesting, some of the turtles dive under the water for brief periods. If your frog happens to be on one of these turtles when it submerges, he will drown. You may of course be excused for wondering why an amphibious creature like a frog would drown, but the frogs in Frogger are apparently unable to swim. On the plus side of things, a lady frog will appear from time to time on one of the logs. If our frog hero manages to land on the spot occupied by his female counterpart, he can earn two hundred bonus points for successfully carrying her to one of the home locations. In addition, a fly may appear in one of the home locations. If a frog manages to reach the lily pad before the fly disappears, he will earn two hundred bonus points (presumably for eating the fly). Unfortunately, crocodiles also have a tendency to pop up in the home locations from time to time.

Other hazards include otters and snakes, which begin to appear after the second level. Should a frog manage to make it safely into one of the home locations, a total of one hundred and fifty points are awarded. Fifty of these points are awarded for successfully reaching a lily pad, and ten additional points are awarded for each hop that takes the frog in a forward direction (a total of ten forward hops are required to get a frog from its starting position to the far side of the river). A level is complete when you have placed a frog in each of the five home locations. One thousand points are awarded for each level completed, and a further ten points are awarded for each second remaining on the clock when a frog reaches a home location. As you have probably surmised, a frog must reach a home location before the timer expires or perish.

You can also lose a life by mistiming your final hop into a home location (the frog must be aligned with the centre of the "lily pad"), staying on a log or a turtle too long and disappearing off the edge of the screen, or jumping into a home location already occupied by a frog. Being eaten by a crocodile, otter, or snake is another possibility, although crocodiles can be used to cross the river in the same way as logs, as long as you remember to stay away from their mouths. Snakes are pretty deadly and should be avoided at all costs. They can turn up on logs, or on the river bank. In developing a strategy for playing the game, it is worth remembering that the left-most home location is the most difficult to get into because logs, which are the objects nearest to the far bank of the river, move from left to right. Needless to say, the game gets progressively harder with each level, with faster moving objects and more predators.

Although Frogger was a huge success in Japan, in 1981 Konami had no manufacturing or distribution facilities in the United States or Europe. They therefore turned to the Sega/Gremlin partnership established by Sega Corporation and Gremlin Industries. The main purpose of the collaboration between these two companies was to distribute Japanese arcade games to overseas markets, and in particular to the US market. Konami originally wanted to call the game "Highway Crossing Frog", but Sega came up with the name "Frogger", which certainly sounds a lot more like the name of a fun game. Although an arcade sequel was not forthcoming, the game was predictably ported to all of the popular game consoles and personal computers of the time. In the three decades or more since it first appeared, sequels, spin-offs, and clones of the game have abounded. Versions are still appearing for popular game consoles, including the Sony PlayStation, Xbox and Wii, and have also appeared for various mobile devices. Numerous online versions of the original game are also available to play.

In the tradition of games such as Space Invaders, PacMan and Donkey Kong, Frogger has left its mark on popular culture. The Frogger character has appeared in children's cartoons and animated films. In fact, the most recent appearance of the character at the time of writing was a cameo role in the Disney animated film "Wreck it Ralph", released in 2012. Almost inevitably, in 1982 Frogger became the subject of yet another game-related song ("Froggy's Lament") by U.S. pop duo Buckner and Garcia. The song featured snippets of music and sound effects taken from the game itself. A 1998 episode of U.S. sitcom "Seinfeld", entitled "The Frogger", depicts one of the show's main characters attempting to procure a Frogger arcade machine (on which his name is still credited with the highest ever score) from a local Pizza parlour. At the time of writing, the highest score ever officially recorded in real life is 970,440 points, and was achieved in July 2012 by Michael Smith of Springfield, Virginia, USA.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Donkey Kong - 1981

Donkey Kong was the iconic game that signaled Nintendo's arrival on the world stage in terms of video gaming. Nintendo had already achieved a degree of success in Japan with their arcade games Sheriff, Space Firebird, and Radar Scope. The last mentioned of these was a Space Invaders clone, first released in Japan in 1980. The domestic success of Radar Scope fuelled Nintendo's ambitions to break into the US video game market, which at the time was booming.

To put things into perspective somewhat, it should be noted that these games were a departure from Nintendo's previous activities in the gaming market. They were programmable games that required relatively advanced electronic hardware. Nintendo had neither the in-house programming skills nor the manufacturing facilities to produce this kind of game on their own. They therefore turned to engineering firm Ikegami Co. Ltd. (also known as Ikegami Tsushinki).

Ikegami was one of several "shadow developers" - companies who provided software development services and electronic hardware to high-profile companies like Nintendo under contract. Their name does not appear in the credits of the original Donkey Kong arcade game, but can be found hidden in the game's read only memory (ROM). Nintendo, for their part, came up with the ideas for the games, designed and built the arcade cabinets, and handled the marketing side of things.

Nintendo president Hiroshi Yamauchi assigned the job of establishing a Nintendo presence in the United States to his son-in-law, Minoru Arakawa. Arakawa decided to use Nintendo's Radar Scope arcade game to spearhead the company's attempt to break into the US market, and placed an advance order for three thousand units with Ikegami. The completed arcade machines were duly shipped to Nintendo's Redmond, Washington distribution centre.

Although Nintendo managed to sell about a third of their Radar Scope arcade games, the game did not prove to be as popular in the United States as it had been in Japan. This left Nintendo with somewhere in the order of two thousand game units that they couldn't sell, which potentially represented a huge loss. Nintendo's dream of gaining a foothold in the US market almost ended there and then. Enter industrial artist Shigeru Miyamoto, who had joined Nintendo straight from college in 1977.

Miyamoto had entertained hopes of designing toys for Nintendo, but had instead been conscripted to design the cabinets and promotional art for Nintendo's coin operated games, including Radar Scope. Miyamoto must have demonstrated considerable talent, because when Arakawa asked his father-in-law for help in finding a way to somehow shift the unwanted cabinets, Yamauchi asked Miyamoto to design a new game to replace Radar Scope.

Nintendo had been negotiating for the rights to create a game based on the comic strip character Popeye. Although they were ultimately unsuccessful in this venture, Miyamoto became fixated on the relationship between the three main characters Popeye, (a sailor, and the character for whom the cartoon is named), Olive Oyl (his often fickle girlfriend) and Bluto (the dastardly and brutish villain who constantly tries to steal Olive away from Popeye).

He also apparently took inspiration from Merian C. Cooper's ground-breaking 1933 film King Kong, as well as from the classic fairy tale Beauty and the Beast. Miyamoto dreamed up a scenario in which the hero is a carpenter who has a pet gorilla and a girlfriend. All right, I know what you're thinking - there has to be a conflict of interests in there somewhere. Sure enough, the gorilla takes a shine to our hero's girlfriend and that's when the trouble starts.

As illustrated by the screenshots above, the game makes use of a cutscene to tell the player what has occurred prior to the start of the game itself. A cutscene is a video sequence over which the player has no control, but which can be used to (literally) set the scene and fill in any missing gaps in the storyline. In this case, the villainous ape of the title (Donkey Kong) has escaped and kidnapped our hero's girlfriend. He carries her to the top the first level of a building under construction (presumably, this is where our carpenter hero works).

Perhaps to emphasise that we are dealing with a large and powerful creature, Kong is shown stamping his feet in a show of rage, displacing several steel girders. Ladders ascending from the top of the highest girder should perhaps alert the observant player to the possibility that there may be further levels of the building above this one. Our hero must ascend the building and rescue his girlfriend using the ladders provided, jumping over gaps, and avoiding the various projectiles hurled at him by the belligerent ape.

Donkey Kong gave rise to a whole new genre of game - the platform game. As the name implies, the player must navigate their character from one platform to the next by running, jumping or climbing. This type of game often involves the use of careful timing in order to ensure that the player's character does not plunge to an untimely death or run head-on into an obstacle. The player skills required are at a significantly higher level than those needed for games such as Space Invaders.

In the first level of Donkey Kong, our carpenter character must run along the steel girders, climb a ladder to get from one girder to the next, and jump over or otherwise avoid the objects thrown by Kong. These objects are at first mostly barrels, including the occasional oil barrel which catches fire and seems to have a life of its own, but will later include other equally lethal objects. It's not as easy to play as you might at first think.

The game introduced other elements not seen, or at least not fully explored, in previous games. There is for example a distinct, albeit somewhat outlandish, storyline. The game's main characters are depicted using cartoon-style graphics, and each is represented by a unique and highly recognisable sprite. Indeed, the two main protagonists would go on to feature in many later Nintendo games, and are still recognisable today, even in their original form.

Another innovation was the use of multiple stages within each level, the ordering of which could change as the player progressed through the levels. One of the abiding myths surrounding the game is that relating to the origin of the game's name, "Donkey Kong".

Some sources claim that the name was originally meant to be "Monkey Kong", but that the name had inadvertently been altered to "Donkey Kong", perhaps due to a blurred fax copy or typographical error. It later emerged, however, that Nintendo's Japanese management team wanted to give the game a name that meant "stubborn gorilla" or "stupid ape", but were unsure how to translate this correctly into English for the American market.

The word "donkey" was allegedly arrived at by consulting a Japanese-English dictionary for an English word that meant "stubborn" or "stupid". The word "kong" is apparently a common Japanese slang term for gorilla. Nintendo also assumed (probably correctly) that most people in the USA had seen, or were at least familiar with, the film King Kong, in which the central character is a giant gorilla.

Nintendo's US marketing team were skeptical at first about Donkey Kong's potential to appeal to the US game-playing public. It was very different, after all, from the popular shoot 'em up games of the period, such as Space Invaders and Asteroids. They were even more doubtful about the name "Donkey Kong", but at Yamauchi's insistence the name stayed. The Japanese management and development team members were far more optimistic than their US counterparts that the game would appeal to a western audience.

Nevertheless, in order to determine what kind of reception the game was likely to receive, Nintendo's marketing team in the US persuaded the proprietors of two bars in Seattle, Washington to set up Donkey Kong arcade machines on their premises. As we now know, the game proved to be every bit as popular as Nintendo had hoped.

Unfortunately, the game also attracted attention of a less desirable nature. Universal Studios, who produced the 1976 King Kong movie, soon became aware of the game and the enormous amount of revenue it was generating (Nintendo were selling over four thousand arcade units per month). Perhaps seeing an opportunity to cash in on this gaming phenomenon, they sued Nintendo for infringement of their rights to the name Kong and the plot of the movie, certain aspects of which had indeed provided inspiration for Miyamoto's game.

Universal lost both the lawsuit and a subsequent appeal. Nintendo were able to prove that universal had themselves used the argument, in respect of the 1933 movie produced by RKO Radio Pictures, that the name Kong and important elements of the plot were in the public domain. The episode demonstrated to Nintendo that they could hold their own, even against one of the giants of the US entertainment industry. It encouraged them to consolidate their new role as a major player in the US video game market.

The anglicised name of the player-controlled character was originally "Jumpman". This at least seems logical, since the character is required to spend a considerable amount of time jumping over gaps or obstacles. It also sounds a little like "Pac-Man", although whether this was intentional or purely a coincidence is a matter for conjecture. In later incarnations, the character's occupation would be changed from carpenter to plumber.

Before Donkey Kong's introduction to the United States, the name "Jumpman" was replaced with "Mario", apparently named after Mario Segale from whom Nintendo rented their office premises. Donkey Kong would be the first of many games featuring either Kong, Mario, or both of these enduring characters. The female character (Jumpman's hapless girlfriend) was initially called "the Lady", but was renamed "Pauline" for the US market after Polly James, the wife of Nintendo's Redmond warehouse manager Don James.

Both the gameplay and the graphic representation of the characters were to a great extent dictated by the limitations of the hardware. In the development stage, Miyamoto worked closely with Nintendo's head engineer Gunpei Yokoi, who was tasked with overseeing the project by Yamauchi. Miyamoto wanted to depict the Mario character as an ordinary working man, someone with whom the average player could identify, which is perhaps why he is depicted as a carpenter (and later as a plumber).

The moustache and cap that were to become such recognisable features of the Mario character came about because they were easier to draw, given the limited number of pixels available, than a mouth and hair. Even the design of Mario's overalls, with the sleeves having a different colour from the body, was designed to make the movement of the character's arms easier to see.

Gameplay was also constrained by hardware considerations. Miyamoto, who was an artist and not a programmer, would run a number of ideas past Yokoi and the other members of the development team to see if they were technically feasible. What Miyamoto wanted to see on screen often proved to be not technically feasible, but the compromise eventually arrived at was usually better than satisfactory. Each level of the game is broken down into four distinct stages, with each stage featuring a twenty-five metre high section of the building under construction.

Mario must reach his girlfriend Pauline to complete each stage, after which she will again be grabbed by Kong. Kong then escapes to the next highest section of the building, with Pauline tucked under one arm. The game is accompanied by a simple but effective musical soundtrack which, although accredited by some sources to Miyamoto himself, is more often (and more plausibly) accredited to sound designer Yukio Kaneoka, who went on to create the music for many of Nintendo's other games.

The first stage of the game is sometimes known as the ramp stage or girder stage. In this stage, Mario must run along the girders and ascend the ladders in order to reach Pauline, jumping over barrels and other projectiles dropped from above by Kong, or destroying them with a hammer (hammers are located at various points throughout the game, and Mario can grab a hammer by positioning himself underneath it and jumping up).

Alternatively, he can try to avoid these obstacles altogether. Using the hammer (which disappears again after a short time interval) has the disadvantage that Mario cannot climb a ladder or jump whilst wielding a hammer. If any of the projectiles (or Kong himself) touches Mario, he loses one of his three lives. If all lives are lost, the game is over. Once Mario reaches Pauline, a heart appears between them . . . only to break and disappear again as Kong recaptures Pauline and carries her off to the next stage.

In the second stage, sometimes called the conveyor belt stage, Mario has to climb ladders to get from one conveyor belt to the next. If running in the opposite direction to a conveyor belt, his progress will obviously be considerably slower than if he is running in the same direction as the belt.

The conveyor belts can also change direction without warning, and Kong again provides plenty of obstacles in the form of buckets of cement and fireballs. From the second stage onwards, Mario can gain extra points by collecting various personal effects dropped by the lovely Pauline as she is being carried off by Kong, such as a hat, a parasol, or a purse.

The third stage is often referred to as the elevator stage, for reasons that should be obvious. Mario must still use the ladders to climb, but at some stage he needs to also use the elevators to get from one side of the screen to the other and gain access to the ladder that will take him to Pauline. Any slip-ups and he will plunge to an untimely death. Kong meanwhile provides plenty of obstacles in the form of fireballs, bouncing springs and weights. Mario must also be careful not to become tangled up in the gears.

The last stage is often called the rivet stage or the long fall, because Mario can remove the rivets that hold the structure together in order to dislodge Kong, who will then fall to his death, allowing Mario to rescue his beloved Pauline. If this happens, Mario and Pauline are reunited and there is a short cutscene, after which the whole process starts again at the next level of difficulty.

The four stages are repeated in each new level, but become progressively more difficult. The order in which the stages appear may also vary, and some stages may even be omitted on some levels, depending on which version of the game you are playing. In the original arcade version, screen twenty-two became known as the kill screen, because a programming error causes Mario to be killed almost as soon as the level begins, and further progress is impossible.

Points are awarded for jumping over objects (or smashing them with the hammer), collecting Pauline's personal belongings, and of course for rescuing Pauline. At the beginning of each stage, a timer starts counting down. On completion of the stage, bonus points are awarded according to how much time is left on the clock. If the timer runs out, Mario loses a life and has to start the stage again from the beginning. By default, the player receives a bonus life if they manage to achieve seven thousand points.

The game's hardware is similar to that of other arcade games of the period. Most of the arcade machines were upright cabinets, with a number of cocktail table versions also being produced. Like Pac-Man, the game employed a Zilog Z80 microprocessor, but had somewhat more advanced sound circuitry. The visual display unit was a vertically oriented raster graphics monitor which could display two hundred and fifty-six colours.

A joystick was used to control Mario's movements (push the joystick left or right to run, and up or down to climb or descend ladders). Two buttons are also provided. One is used to make Mario jump, and the other is used before the game commences to select either a one- or two-player game. Pushing the joystick left or right while pressing the jump button makes Mario perform a running jump. For the home console and home computer versions of the game, a keypad or keyboard is used to control Mario.

Donkey Kong has probably spawned more sequels, clones and spinoffs than any other video game to date, including the hugely successful Super Mario Brothers. The first arcade sequel to Donkey Kong was called Donkey Kong Junior, and was released in 1982. In this game, Mario and Donkey Kong swap roles. This time Mario is the villain of the piece having imprisoned the unfortunate Kong.

Donkey Kong Junior is Donkey Kong's son, and must rescue his father from Mario's clutches. The second arcade sequel, released in 1983, was called simply Donkey Kong 3. This sequel did not feature Mario and was more like a shooter than a platform game. It features a character called Stanley who, armed only with an insecticide spray gun, must protect the plants in his greenhouse from being devoured by a swarm of angry bees, apparently stirred up by the actions of Donkey Kong.

The huge success of the arcade game versions naturally led to numerous ports of these games to other platforms. A simplified version of Donkey Kong was ported to Nintendo's own hand-held Game & Watch console, and versions of Donkey Kong and its spin-offs have appeared on just about every hand-held or home console produced by Nintendo up to the present day, including the Nintendo Entertainment System (NES), Super Nintendo Entertainment System (SNES), Gameboy, Gameboy Advance, Nintendo DS, and of course the Wii. No doubt there are more Donkey Kong spin-offs to come.

In the wake of Donkey Kong's initial success, US toy company Coleco were competing with Atari for the right to produce the home console version, a contest in which Coleco triumphed. As a consolation prize, Atari won the rights to port the game for home computers, and versions duly appeared for just about every popular home computer of the day, including Atari's own 8-bit computers, the Apple II, and the IBM PC.

Although the Donkey Kong franchise is still going strong today, there was a period of approximately ten years (from 1984 to 1994) when nothing very much happened, probably due in part to the video game market crash that occurred in 1983. There was a resurgence of activity in the mid-nineties, when the original game was resurrected for Nintendo's Gameboy hand-held console.

The same year saw the emergence of a new generation of games based around the character of Kong, together with a whole host of new characters. The first of these was Donkey Kong Country, developed by the British video game development company Rare Ltd. Rare followed up in 1995 with Donkey Kong Land. Both games were well received, and both have spawned a number of sequels and spin-offs.

Donkey Kong has been around in one form or another now for over thirty years. Although the glory days are perhaps over, there is no sign of him disappearing from the video game stage any time soon. Kong's legacy goes beyond the world of video gaming. Kong himself and many other memorable characters from the Nintendo gaming world, including Nintendo's best known character Mario, have starred in their own television shows and cartoons.

Kong and company have been featured on cereal packets, T-shirts, lunch boxes and literally hundreds of other products. Like Pac-Man before him, Donkey Kong was the subject of a song from pop duo Buckner and Garcia called "Do the Donkey Kong", released in 1982. In fact, Kong-related characters, music, sound effects or references have popped up in just about every form of popular media during the last thirty years or so.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Castle Wolfenstein - 1981

Castle Wolfenstein is variously described as a stealth game, an action-adventure game, and a shooter, and frequently as all three. The term stealth is used to illustrate the fact that the game's main character spends a lot of their time trying to evade capture rather than seeking confrontation. There are however occasions where our hero must resort to the use of weapons, hence the game is also a shooter.

The term action-adventure is a fairly wide ranging one, but it too is appropriate for this game. The game was developed by the Baltimore-based company Muse Software (the name was derived from the term Micro Users Software Exchange) founded in 1978 by Ed Zaron, Silas Warner and Jim Black, who had met whilst working for finance company Commercial Credit.

The company initially set out to write computer games for the Apple II personal computer, but later expanded their ambitions to include other popular personal computer systems, including the Commodore 64, Atari's eight-bit personal computers, and the IBM PC.

The Castle Wolfenstein program itself was primarily the work of Silas Warner, and is noteworthy not only because it is one of the first games of its kind ever written, but also because it broke new ground in terms of what was technically possible for computer games. The game is set in World War II, and the game's main character (who is never actually named) is a prisoner held in a Nazi fortress (the aforementioned Castle Wolfenstein).

The movements and actions of the prisoner are controlled by the player. The object of the game is for the prisoner to negotiate the various levels within the castle, find a set of secret Nazi war plans, and escape. If the prisoner is successful and escapes together with the plans, they are promoted to a higher rank and can play again at a new level of difficulty (there are eight ranks in total).

The above screenshot is of the opening screen to the DOS version of Castle Wolfenstein, available from the My Abandonware website. The game can be played on a modern computer using DOSBox, although you will need to adjust the CPU speed within DOSBox to a relatively low value (depending on your computer's processor hardware) in order to get the game to run properly. Once the game is running, the player is given the choice of controlling the game with the keyboard or a joystick.

The game itself utilises a "top down" perspective in the sense that the layout of the rooms in each level are shown from above, although the characters and objects in the game are drawn upright. The graphics in the game are crude by today's standards (the game uses a four-colour CGA palette), but were considered good for their time.

The protagonists in the game come in two different flavours - the guards, who are identified by a large swastika on their uniform, and SS officers, identified by the letters "SS". Of the two, the latter are more difficult to kill (because they have bullet-proof vests) and are generally more dangerous. In addition, the rooms in the various levels frequently feature chests, usually locked, that can contain all manner of things from food and drink to uniforms and explosives. The prisoner is armed with a handgun loaded with ten bullets, given to him by a doomed fellow prisoner.

According to the TV Tropes pop-culture wiki, the original version of the game featured the following (more or less) self-explanatory introductory text:

"Welcome to CASTLE WOLFENSTEIN, mate! The Nazis brought you here to get information out of you before they kill you. That's what this place is for - if you listen you can hear the screams. They've already worked me over and I'll never get out alive, but maybe you can with this gun. It's standard issue - each clip holds 10 bullets, and it's fully loaded.

Be careful, mate, because every room in the castle is guarded. The regular guards can't leave their posts without orders, but watch out for the SS stormtroopers. They're the ones in the bulletproof vests and they're like bloody hounds. Once they've picked up your trail they won't stop chasing you until you kill them and you almost need a grenade to do that.

CASTLE WOLFENSTEIN is full of supplies too. I know one chap who found a whole German uniform and almost sneaked out past the guards. He might have made it if he hadn't shot some poor sod and got the SS on his trail. If you can't unlock a supply chest, try shooting it open. Now I wouldn't go shooting at chests full of explosives . . .

One more thing. The battle plans for operation Rheingold are hidden somewhere in the castle. I'm sure you know what it would mean to the Allied high command if we could get our hands on those . . .

They're coming for me! Good luck!

AAIIIIIEEEEEEE . . . . . ."

The prisoner can employ various tactics in order to find the secret plans and make good their escape. The most effective tactic is probably to avoid detection by wearing a guard's uniform, taken either from the body of a dead guard or from one of the chests. Shooting guards is generally a last resort, since it uses up the very limited supply of ammunition and attracts the attention of any other guards in the room.

In addition, killing an SS officer requires multiple shots (although once you have attracted the attention of an SS officer they will follow you from room to room, so you may eventually be forced to resort to violence to get them off your trail). The guards will also surrender to you if you get the drop on them and are aiming your gun at them (even if the gun is empty, since they have no way of knowing whether the gun is loaded or not).

The player can find various useful items as the game progresses, both by opening the chests scattered throughout the castle and by searching any dead or captured guards. The useful items available include hand-grenades, ammunition for the handgun, uniforms, bullet-proof vests, keys, and of course the all-important war plans. Note that the wearing of a guard uniform will fool the ordinary guards, but not the SS officers.

Hand-grenades can be used to kill an SS officer, or to blast through locked doors or internal walls, although like gunshots they will attract unwanted attention. Locked chests can be opened by picking the lock, although this requires a certain amount of time. The process can be speeded up by shooting the lock, but this carries the risk that, if the chest contains explosives, the player will blow themselves up. It also uses up ammunition, and the chest could in fact be empty.

In addition to useful items, chests can contain things that serve no practical purpose from the point of view of actually playing the game. Examples include Liebfraumilch (a type of German Wine), Schnapps (a somewhat stronger drink), Bratwurst (a type of German sausage), medals, cannonballs, and even Eva Braun's diaries! If the player actually drinks any of the alcohol, they become temporarily disoriented, although eating Bratwurst apparently counteracts the effects of the alcohol.

The player can also be temporarily stunned if they walk into a wall. To add to the game's atmosphere, digitised speech is frequently heard in the form of guards shouting commands in German (or perhaps dying rather noisily). This was a new innovation in computer gaming, introduced by Warner, that utilised the computer's built in speaker (at that time, dedicated sound cards were still a thing of the future).

The game ends when the player either manages to escape from Castle Wolfenstein (with or without the plans), or is shot or captured by a guard. In total, there are sixty rooms (or levels) in the castle, spread over five floors. The layout of each room does not change from one instance of the game to the next, but the sequence in which the levels are connected is randomly generated at the start of each game.

Mastering the keyboard controls represents perhaps one of the greatest challenges of the game. The player must memorise eight separate keys just to move around in the various horizontal, vertical and diagonal directions (essentially, equivalent to eight points of the compass). In addition, another eight keys are used to aim the player's weapon in a particular direction. Two more keys are used to halt movement or fire the weapon.

In 1984, Muse Software released a sequel to Castle Wolfenstein called Beyond Castle Wolfenstein, again largely the work of Silas Warner. This time, the object of the game is for our hero to break into Hitler's command bunker complex and locate a bomb hidden somewhere in the complex by allied undercover agents. They must plant the bomb in the vicinity of Hitler and escape from the bunker before the device explodes.

The gameplay is very similar to that of Castle Wolfenstein, with a few new features and improved graphics. The storyline is of course based on the real-life attempt to assassinate Hitler, led by Claus von Stauffenberg, which culminated in failure on July 20th, 1944.

Although initially successful and enjoying a multi-million dollar annual turnover, Muse Software eventually fell victim to the slump in the home computer software market that occurred in the early 1980s. They filed for bankruptcy protection under Chapter 7 in 1985, and eventually ceased trading in 1987. The two Wolfenstein games had left a lasting impression, however, and were the inspiration for id Software's revolutionary 1992 first person shooter Wolfenstein 3D.

Having sought permission to re-use the Wolfenstein name from Silas Warner, id based their game on a similar theme. This time around, the hero has a name - William "B.J." Blazkowicz. In the first episode of the game, Blazkowicz must escape from the Nazi-infested Castle Wolfenstein. Subsequent chapters feature a series of missions carried out by Blazkowicz against the Nazis. Wolfenstein 3D is credited with being the game that both initiated the first person shooter genre of computer games and made them popular. Such is Castle Wolfenstein's legacy.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Pac-Man - 1980

Pac-Man is one of the most successful video games of all time. The game was created over a period of about a year by a team of developers at Namco led by Tōru Iwatani, who at the time was in his late twenties. Namco were looking for a game that would appeal to a wide audience. The most popular arcade games of the day were "shoot 'em up" type games such as Taito Corporation's Space Invaders or Atari's Asteroids that appealed mostly to young males.

Iwatani set about searching for themes that might also appeal to a female audience. In so doing he explored ideas based on fashion, romance, and (for reasons best known to himself) eating. According to Iwatani, inspiration arrived one day when he was having pizza for lunch and looked at the shape formed by a pizza with one slice removed. The missing slice looked to Iwatani like an open mouth, and apparently gave him the idea for a character that traversed a maze eating everything in its path. The screenshots below were taken from the full version of Pac-Man formerly available from Jenkat Games (sadly this appears to be no longer available for download, but you can find a playable online version here.

The origins of the name Pac-Man are not entirely clear. On the one hand, Iwatani claims that the name derives from the expression "pakku pakku" which is a Japanese slang term used to describe the sound of the mouth opening and closing. On the other hand, when the game was first released in Japan it was in fact called Puck-Man, a name apparently based on the fact that the central character has a shape similar to an ice hockey puck.

With the need to appeal to a female audience still in mind, Iwatani had decided to provide some "cute" protagonists for the ever-hungry pizza-shaped character we know today as Pac-Man. These protagonists take the form of four cartoon ghosts that chase Pac-Man around the maze and attempt to catch him.

When the game was first released in Japan, the reception was initially somewhat muted. As predicted, the game did appeal to a wider audience, but did not immediately achieve the kind of popularity enjoyed by Space Invaders or Asteroids. When the game was released in the United States, however, it was a very different story. Namco licensed the game for distribution in the USA to the Midway division of Chicago-based Bally Manufacturing (the same company to which Taito Corporation had licensed Space invaders).

As with previous games, Midway produced both upright cabinet and cocktail table versions of the game. They decided to change the name of the game from Puck-Man to Pac-Man, apparently due to concerns that the original name could too easily be changed into something unsavoury. I can't imagine what they had in mind.

Like other popular video arcade games of its time, Pac-Man was easy to play but difficult to master. The game as originally implemented has two hundred and fifty-six levels. The original design allowed for the game to "roll over" at the final level, taking the player back to the first level and theoretically allowing the game to be played indefinitely.

In practice, a software bug causes the screen display to become corrupted once the player reaches the last level, making further progress impossible. Only a relatively small number of people can claim to have actually completed all of the playable levels. The first to go on record was Billy Mitchell of Hollywood in Florida, USA. Mitchell achieved this feat in July 1999, taking approximately six hours and reportedly achieving a score of over three million points (3,333,360 to be exact).

Game play is relatively simple, with the movement of the Pac-Man character being controlled by the player. On the arcade version and most console versions, Pac-Man is moved left, right, up, or down using a four-way joystick. Versions written for personal computers required the player to control the character using the keyboard. Pac-Man must navigate the maze, eating the evenly-spaced circular pellets distributed throughout the maze.

According to most sources, there are two hundred and forty pellets on the board in total, each worth ten points. The four ghosts are meanwhile trying to catch Pac-man. If Pac-Man is caught by a ghost, the player loses one of their three lives. If all three lives are lost, the game is over. There are also four "power pellets" on the board (worth fifty points each) which, when consumed by Pac-Man, cause the ghosts to change colour for a short time, during which they too can be eaten.

Immediately after Pac-Man consumes a power pellet, the ghosts all turn blue and change direction. If Pac-Man manages to catch a ghost, only the ghost's eyes remain. These can be seen scurrying back to the ghost's original position in the middle of the screen, where the ghost is returned to its normal state. The player gets two-hundred points for eating a single ghost, four hundred points for two in succession, eight hundred points for three in succession, and sixteen hundred points for eating all four ghosts in one go.

The power pellets are only effective for a short time, after which the ghosts become invulnerable once more. Just before they change back to their normal state, the ghosts "flash", with their colour alternating between blue and white. The length of time for which the power pellets affect the ghosts is reduced with each new level, until they eventually have no effect at all.

Once all of the pellets have been consumed, the level is over and the next level may begin. In between some of the levels there is a short "interlude" during which a brief animation of some description can be seen, presumably to give the player a break. During gameplay, a piece of fruit or some other object will appear in the maze from time to time. Eating one of these objects earns the player far more points than the standard pellets, although it usually involves making a detour, which in turn increases the chances of being caught by a ghost.

Different kinds of object (they are mostly fruit) generate different numbers of points. At the bottom end of the scale, a cherry is worth two hundred points. The most valuable object is a key, which is worth five thousand points. On achieving ten thousand points, the player is usually awarded a single bonus life.

The behaviour of the ghosts, while seemingly random, is in fact deterministic (i.e. it follows a pre-programmed pattern). According to Tōru Iwatani, each ghost has been programmed to behave in a certain way using a different algorithm. The red ghost (known in the US version of the game as "Blinky") is programmed to chase Pac-Man. Both the pink ghost ("Pinky") and the pale blue ghost ("Inky") try to position themselves ahead of Pac-Man, although they don't behave exactly alike.

The behaviour of the orange ghost ("Clyde") is supposed to be random, although analysis has reportedly shown that it tends to follow Pac-Man most of the time. All of the ghosts will occasionally exhibit what appear to be uncharacteristic behaviours, but there is still an underlying pattern. As players gain experience, they can learn to predict the behaviour of the ghosts and use this knowledge to their advantage.

Contrary to Iwatani's initial assumption that Pac-Man would not be particularly successful outside of Japan, the game became a world-wide phenomenon and was played by tens of millions of people. It was the highest grossing game of its time, both in terms of arcade hardware sold and the revenue generated by arcade machines. The game also had an enormous impact in terms of popular culture, spawning merchandise that included everything from Pac-Man T-shirts, lunch boxes and books to Pac-Man air-fresheners and breakfast cereals.

There were countless publications dealing with strategies for playing the game. Even today, most people are familiar with the yellow pizza-shaped character. The game inspired an animated TV series produced by Hannah-Barbara that ran on the ABC television network in the USA during 1982 and 1983, and was even the subject of a hit song called "Pac-Man Fever" (from the album of the same name) written and performed by US pop duo Buckner and Garcia. The song reached number nine in the US Billboard Hot 100 chart during 1981.

Thanks to its phenomenal success, Pac-Man clones, spin-offs and re-vamped versions of the original game inevitably followed, many of which were not authorised by Namco. Perhaps one of the best known, and by far the most successful, was Ms. Pac-Man. This unauthorised Pac-Man spin-off was created by the General Computer Corporation in 1981 and sold to Midway Manufacturing.

The idea was presumably to cash in on the fact that the original Pac-Man game appealed to a female audience as well as to a male audience. A bow was added to the top of Pac-Man's head. The character was also given an eye, and a mole, presumably to reinforce the fact that the character was a female.

Other enhancements included new maze layouts, new music, and new colour schemes. Midway transferred the rights for Ms. Pac-Man to Namco in 1982, apparently to head off a threatened law suit. They continued to make unauthorised sequels, however, which is probably why Namco later dropped Midway as its US partner in favour of Atari.

The game was also ported (and for that matter continues to be ported) to just about every platform imaginable, including game consoles, personal computers and mobile devices. One of the very first ports (and one of the most infamous) was created by Atari for their Atari 2600 game console and released in 1982.

Development of the game was assigned to Atari programmer Tod Frye, who faced problems from the very start due to the relatively short time frame allowed for development by Atari's management, and the fact that the target game cartridges had far less memory than the original arcade game hardware. The Atari 2600's MOS 6507 microprocessor was also far slower than the Zilog Z80 microprocessor used in the arcade version.

In the end, so many compromises had to be made that the Atari version of Pac-Man was significantly different in appearance to the original. In addition, in order to conserve memory, the four ghost characters were redrawn in alternating frames, creating a flickering effect on screen that many players found disconcerting.

The game sold five million copies, and was the best-selling Atari game up to that time. This initial success was accompanied by an increase in sales of the Atari 2600 game console itself. Unfortunately, Atari had greatly overestimated demand, producing a total of twelve million game cartridges. This meant that they were left with five million cartridges unsold.

To make matters worse, many copies of the game were returned to sales outlets by customers who were unhappy that the game was so different from the original arcade version. Later ports created by Atari for their other consoles and personal computers were far better, but the damage to Atari's reputation had already been done.

The episode marked a turning point in Atari's fortunes, which went into decline as consumer confidence in the company faded. It is also often cited as a contributing factor in the so-called "video game crash" of 1983.

The initial success of Atari's home console version of Pac-Man led to a number of retailers, some of whom had never previously stocked video games, buying in large stocks of game cartridges in the hope of cashing in on the apparent sudden increase in the demand for home video games. Things reached a stage where even drugstores and filling stations were offering game cartridges for sale. The end result was a glut of video games on the market, many of which were poor quality imitations or bootleg copies of the popular titles of the time.

Despite these events, Pac-Man itself has continued to prosper and can still be found today on numerous platforms. The game introduced a number of new concepts to the world of video gaming, and its influence can be seen in many of the successful games that followed. Its broad appeal can be attributed to a number of characteristics. It was easy to play, featured characters that were both colourful and memorable, and contained no overt violence.

There was also an underlying humour to the game, epitomised by the animations that appeared between levels. These animations typically showed Pac-Man being chased by, or chasing, one or more ghosts across the screen. In short, it was a fun game to play.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Missile Command - 1980

Missile Command was a popular Atari arcade game that followed hot on the heels of Space Invaders and Asteroids. Although perhaps not in the same league as its predecessors in terms of the total amount of revenue it generated, Missile Command was nevertheless financially successful, and can be counted as one of the classic video arcade games. For some, it was also a chilling reminder of the very real dangers of a nuclear confrontation.

At the time of its release the Cold War was very much ongoing, and Russian forces had occupied Afghanistan during the previous year, raising global tensions. The game concept is simple. The player must defend six cities from multiple incoming missiles using their own anti-missile missiles. As with Space Invaders and Asteroids, this is a game that ultimately cannot be won. The player simply tries to survive as long as possible. The more incoming missiles the player manages to destroy, the higher their score will be.

The idea for the game was apparently inspired by a magazine article about satellites which was read by Atari's president Ray Kassar, who passed the article to Atari engineer Lyle Rains. Rains in turn assigned the task of designing the game to developer Dave Theurer. The original requirement was for a game in which the player had to defend a number of cities on the coast of California, including San Francisco, Santa Barbara and Los Angeles, from a nuclear missile attack.

The explicit identification of geographical locations was later dropped from the specification, possibly because members of the development team were uncomfortable with the idea of a game in which actual US cities were being targeted by nuclear missiles. Even so, Theurer and several other members of the development team reportedly suffered from nightmares during the development process that involved the destruction of US cities in a nuclear holocaust.

The game was originally intended to be called "Armageddon", the name favoured by the Atari design team. Atari's management disagreed, however, asserting that the target audience would not grasp the significance of the name. The apocalyptic nature of the game is at least acknowledged on the final screen, in which the message "The End" replaces the more familiar "Game Over".

If the player has achieved a sufficiently high score, the end screen is replaced by a screen that prompts the player to enter their initials. There is a nicely ironic touch in one scene of the film Terminator 2: Judgement Day. One of the film's main characters, the young John Connor, is seen playing Missile Command on an arcade machine.

Like Asteroids before it, Missile Command employed a MOS 6502 processor, although the display was implemented using raster (bitmapped) graphics, and the sound was controlled by a single integrated circuit. The arcade version of the game was produced in a variety of cabinet styles, including upright and cocktail table versions. Missile Command also enjoyed a colour display, with a palette of eight colours.

One interesting innovation was the use of a trackball, which was used to position the cursor on the screen. The trackball replaced the buttons typically used up until that time to move on-screen objects left and right, or up and down. At the time, pointing devices such as the computer mouse were still not widely used, with user input on most personal computers still restricted to the keyboard. Buttons were still used to launch missiles from the missile batteries controlled by the player.

Gameplay is relatively straightforward. The player is in control of three missile batteries, each of which has ten missiles. The missiles are launched using a launch button (each missile battery has its own button). There are six cities in total, situated at points along the bottom of the screen. Once the game has started, inbound missiles begin to appear at the top of the screen. The player's task is to destroy these inbound missiles using their own missiles before they can reach their targets (which can be either the cities or the player's missile batteries).

The player can target the inbound missiles by using the trackball to position the cursor (which takes the form of a cross-hair) just ahead of an incoming missile. When the player launches a missile, it homes in on the cursor's position at the time the missile is launched, after which the player can move the cursor in order to target another inbound missile. The game is over when all of the cities have been destroyed.

If the missiles (which keep on coming) were the only problem you had to deal with, life would be far too easy. Well, that was the way the Atari game designers saw it, anyway. From the second wave of missiles onwards, for example, some of the inbound projectiles will split up into several independently-targeted warheads. If a city or a defensive missile battery is hit by an incoming missile, it will be totally destroyed. Destroyed cities are not restored until the player has achieved a certain number of points, but missile batteries are restored at the end of each attack wave.

If a player uses up all of their missiles, or if all of their missile batteries are destroyed, they are defenceless until the next wave begins. After the initial wave of incoming missiles has either been destroyed or reached its targets, the player is awarded points for incoming missile destroyed (twenty-five points each), for any cities that remain intact (one hundred points each), and for any unused defensive missiles (five points each).

From the second wave onwards, the player is faced with additional protagonists in the form of a "killer satellite" and a bomber, both of which traverse the screen horizontally, and both of which may launch additional missiles. Destroying a killer satellite or a bomber earns the player an additional one hundred points. Successive waves produce greater numbers of incoming missiles moving at greater speed.

Presumably to compensate for the increasing level of difficulty, the basic points awarded for destroying enemy targets, the points awarded for any surviving cities, and the points awarded for unused missiles is increased every two waves by applying a multiplication factor. For example, the points awarded are doubled for the third and fourth waves, trebled for the fifth and sixth waves, and so on. From wave eleven onwards, the points are awarded using a multiplication factor of six.

For every ten thousand points scored, the player is awarded a bonus city. Once awarded, the bonus city will only appear on screen once the current wave is complete, and then only if there are less than six cities already on screen. To spice things up even more, the game designers at Atari decided to add a "smart bomb" that appears during wave five.

The smart bomb (as its name suggests) has a certain amount of intelligence in the sense that it can detect a defensive missile detonation and attempt to avoid it. Although not invulnerable, this makes the smart bomb more difficult to destroy than other inbound missiles (destroying a smart bomb earns an additional one hundred and twenty-five points).

Defensive strategies mainly hinge on being able to anticipate where incoming missiles will be at a certain point in time and trying to ensure that one of your defensive missiles detonates in that location at the right time. The defensive missile will detonate at the location pinpointed by the cursor's cross-hairs when the launch button is pressed, and the detonation will have a significantly large blast radius centred on that point. With careful targeting and a certain amount of foresight, it is possible to take out two or more enemy warheads and/or killer satellites and/or bombers with a single missile.

The Atari game designers pretty much knew that they had another hit arcade game on their hands because of the number of Atari staff playing the game in their free time (and sometimes during work time). The game was duly ported to the Atari 2600 game console, as well as to other Atari consoles and personal computers. The console version, however, removes the action from planet Earth altogether. The scenario in the game manual is described as an interplanetary conflict between the warlike inhabitants of the planet Krytol and the peaceful (though apparently heavily armed) inhabitants of the planet Zardon.

Atari also licensed the game to Sega for the European market, and to Taito for the Japanese market. In fact, the popularity of the game was such that it has appeared on nearly every platform that has emerged since 1980, including mobile devices such as the iPad and iPhone.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Asteroids - 1979

Asteroids was Atari's response to Taito Corporations's Space Invaders, and became their all-time best-selling game. Atari would sell somewhere in the order of seventy-thousand arcade game machines, generating approximately one hundred and fifty million dollars in revenue, while the machines themselves made hundreds of millions of dollars for operators.

Atari's original vision was for a game called Cosmos, which was virtually a clone of the Space Wars game released by Cinamatronics in 1978 (which was itself based on Spacewar!), with a few asteroids added for effect. Atari engineer Lyle Rains, who was developing the concept for the game, hit on the idea of giving the asteroids a more prominent role. The player would be required to pilot their spaceship through the asteroid field, without colliding with any of the asteroids. The spaceship itself was armed with a weapon, and points would be awarded for destroying as many asteroids as possible.

Rains asked Atari game designer and programmer Ed Logg for his input. Logg liked the basic concept but thought the game still needed to feature alien spacecraft. Logg had played both Spacewar! and the coin-operated Galaxy Game (which was based on Spacewar!) while a student at Stanford University, and was keen to ensure that both the spacecraft and the asteroids themselves should behave in accordance with the laws of physics.

In order to achieve this, Logg realised that he would need a relatively high display resolution. The resolution of available raster (bitmapped) graphics hardware was simply not high enough for what he had in mind, so he insisted on the use of a vector graphics display. Atari had already invested a significant amount of time and effort into developing vector graphics hardware, and had used it in their implementation of the Lunar Lander arcade game.

The Lunar Lander game would never achieve either the widespread popularity or financial success of other titles released during the same period (although I distinctly remember playing this game in an arcade on more than one occasion) but it ably demonstrated the capabilities of Atari's digital vector generator (DVG). Atari engineer Howard Delman, who had refined the prototype hardware for Lunar Lander, was asked to produce a suitably modified version of the DVG hardware for Asteroids.

Delman would also design the circuitry used to generate Asteroids' digital soundtrack. Rains turned over the design and programming of Asteroids to Logg, who was assisted in this task by fellow Atari employee Dominic Walsh. Logg knew the game would be a smash hit when, during the development process, Atari employees had to be prised away from a version of the game running on a prototype arcade machine so that development work on the game could continue.

Initial demand for the game was so great that Atari ceased production of the Lunar Lander arcade machines in order to meet the demand for Asteroids. In fact, the first two hundred or so units shipped were apparently built using cabinets originally intended for Lunar Lander. Once installed in arcades, Asteroids was so popular that arcade operators reportedly had to increase the size of the box used to collect the coins inserted by players.

Opinions vary on whether Asteroids replaced Space Invaders as the most popular and financially successful arcade game of its time. In fact, the two games often appeared side-by-side in arcades, and both were enormously successful. Both were relatively simple in terms of gameplay, both were addictive, and both featured an electronic soundtrack that increased in tempo as the speed of the game increased.

Arguably, a large number of people (myself included) found both games equally enjoyable, though perhaps in different ways. Asteroids probably provided more variety in terms of the challenges faced by players, as well as more scope for developing strategies in order to achieve a high score.

The game itself places the player in command of a spaceship with a forward-firing weapon, initially at the centre of the screen. The player can use thrusters to maneuver the ship and has an unlimited supply of ammunition. The major threat comes in the form of several large asteroids that move randomly across the screen in different directions. If the spaceship collides with one of these objects, it is destroyed. When it has been destroyed three times, the game is over.

The player can fire their weapon at the asteroids to destroy them, but an initial hit will only succeed in breaking the asteroid into two smaller asteroids, each of which moves faster than the original, and each of which can potentially destroy the spacecraft. Shooting either of these smaller pieces produces two even smaller asteroids that move even faster. Once you shoot these smallest asteroids, however, they will be totally destroyed and no longer pose a threat.

As if things were not difficult enough, a further threat is provided in the form of flying saucers that appear at random time intervals, move horizontally (and sometimes diagonally) across the screen, and try to destroy the spaceship (either by firing their weapons at it or by colliding with it). There are two different types of saucer. The larger of the two is the least dangerous by virtue of the fact that it fires seemingly at random, and presents a larger target. The smaller saucer is more dangerous, because it moves faster and appears to be able to target the player's spaceship far more accurately.

The playing field is levelled a little by the fact that the flying saucers are also destroyed if they collide with an asteroid. One interesting feature of the game is the hyperspace option, undoubtedly copied from Spacewar!, which allows a player to get out of a tight spot by making a hyperspace jump. This manoeuver is only meant to be used as a last resort, as it carries with it the risk of reappearing in the path of an asteroid or an enemy projectile (or even occasionally self-destructing).

Shooting a large asteroid generates twenty points. Successively smaller asteroids are worth more points, with the smallest being worth one hundred points. Destroying the larger of the two types of flying saucer is worth two hundred points. The greatest number of points is achieved by destroying the smaller saucer, which will gain the player one thousand points.

Perhaps due to a certain lack of foresight on the part of the game designers, the maximum number of points that can be achieved is just short of one hundred thousand points, at which point the score reverts to zero (many players quickly developed sufficient skill to achieve the maximum score). Once all of the asteroid fragments and any remaining saucers have been destroyed, the game starts again with a larger number of slow moving asteroids (up to a maximum of twelve). As the player's score increases, the speed and targeting accuracy of the smaller flying saucer also increases.

The game has a "wrap-around" feature that allows a moving object to disappear off the edge of the screen and reappear at the corresponding point on the opposite edge, moving with the same velocity (i.e. in the same direction and at the same speed). This applies to asteroids, spacecraft, flying saucers and weapon projectiles. On achieving a sufficiently high score, a player can add their score to the high scores listing, together with their initials.

Seasoned Asteroids players developed a number of high scoring strategies, some of which involved exploiting "bugs" in the game's program. One such strategy used a bug in the earliest version of the game that allowed the player to hide their spaceship in the area occupied by the score and pick off targets prom a position of relative safety. Needless to say, these glitches were addressed in later versions of the game, since they allowed a sufficiently skilled player to play the game indefinitely without parting with any more money.

The arcade version of the game came in various forms, the most popular being the upright cabinet and the cocktail table version. Players control the spacecraft using five buttons. Two buttons are used to rotate the spacecraft (left or right), one button fires the main thruster, another button fires the spacecraft's weapon, and the last button is used to initiate a hyperspace jump.

The electronics hardware includes a MOS Technology 6502 8-bit microprocessor that executes the game's program code. The digital vector generator (DVG) developed by Atari themselves receives graphics commands from the 6502 microprocessor and sends the appropriate signals to the high-resolution monochrome vector graphics CRT monitor in order to draw the screen display.

The game's audio tones are generated by a number of dedicated circuits, each of which is activated by the microprocessor writing to a different address in memory. Each of the buttons used by the player to control the game is mapped directly to a specific location in the microprocessor's address space.

The game code itself requires just six kilobytes of read-only memory (ROM), with a further two kilobytes of ROM required for the vector data for the various onscreen objects and text. Even so, porting the game to the Atari 2600 home console presented a challenge to Atari engineer Brad Stewart (to whom the task was assigned), since the Atari 2600 could only address four kilobytes of memory. Stewart came up with a fairly ingenious bank-switching scheme to get around this limitation, which involved the processor switching backwards and forwards between two separate four-kilobyte memory banks.

The game was subsequently adapted for a number of home game consoles, both Atari's own and those of other console manufacturers, under license. The console versions were programmed using raster graphics rather than vector graphics, but managed to retain the appeal of the original version. Versions of the game also appeared on Atari's 8-bit home computers, and versions would later appear for a number of other personal computers including the IBM PC.

Asteroids inevitably spawned a number of sequels, the first of which was Asteroids Deluxe, released in 1980. New features included a shield that replaced the original hyperspace feature, rotating asteroids, a new kind of alien flying saucer, and a redesigned cabinet intended to give the display a more three-dimensional appearance. Later sequels from Atari include Space Duel in 1982 and Blasteroids in 1987.

It is a tribute to the success of Asteroids that it has been often imitated, spawned many clones, and been ported to just about every platform possible. The game survives to this day in innumerable formats, including versions for the PC, home game consoles, mobile devices, and countless web-based simulations. If you have never played this game before, and want to experience for yourself just how addictive it can be, you can try one of the online versions referenced above, or play the online version on Atari's official website here.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Space Invaders - 1978

Space Invaders is probably one of the best-known and most fondly remembered arcade games of any description in the history of video gaming. It was the creation of Japanese game developer Tomohiro Nishikado, and was released by the Taito Corporation of Japan in 1978.

Prior to the arrival on the scene of Space Invaders, video arcade games had not made much of an impression in Japan. The most popular arcade game at the time was something called Pachinko, which was essentially a Japanese version of the "one-armed bandit" coin-operated gambling machine. Following the release of Space Invaders, large numbers of Pachinko machines were rapidly replaced by Space Invaders cabinets. The arcade machines were originally manufactured by Taito in Japan, and were later manufactured under license in the United States by the Midway division of the Chicago-based Bally Manufacturing Corporation.

Nishikado reportedly took his inspiration from a number of sources, including Atari's Breakout game, Byron Haskin's 1953 film adaptation of H.G. Wells' War of the Worlds, and the film Star Wars which first appeared in cinemas in 1977. He spent a year developing the game and its associated hardware. His intention was always to produce a shooting game of some description in which the targets would be moving objects, but the parameters shifted somewhat during the development process.

The targets were originally intended to be tanks, planes or ships, but Nishikado was not happy that he could create a convincing enough game scenario involving this kind of military hardware, given the technical limitations within which he had to work. He briefly considered depicting soldiers as the targets, but apparently found the idea distasteful. Shooting aliens appears to have been both the most practical and the most palatable solution.

The end result, as with Atari's Pong, was a deceptively simple video game that captured the imaginations of millions of people. The game became so popular in Japan that it created a shortage of the hundred-yen coins required to play the game, and supplies had subsequently to be increased. The game allegedly spawned a mini crime wave, with youths carrying out grocery store robberies in order to acquire money to play the game.

Parent-teacher associations in Japan are reported to have attempted (unsuccessfully) to have the game banned on the grounds that it was causing a truancy epidemic. Space Invaders achieved similar success in the United States and Europe. The medical profession in the US reportedly identified ailments such as "Space Invaders Elbow" and "Space Invaders Wrist", while in the UK attempts were made to bring a bill before Parliament to ban the game due to its addictive nature and allegations that it caused "deviancy".

As for the game itself, the aim is simple - destroy as many alien spacecraft as possible in order to achieve a high score and stop the aliens invading Earth. The player is confronted with row upon row of alien spacecraft that traverse first one way and then the other across the screen. Each time the alien fleet reaches one side of the screen or the other, the entire fleet moves one step closer to the bottom of the screen.

The player controls a laser cannon that can be moved left and right across the screen, along the bottom. The laser cannon can be used to destroy alien ships, but can itself be destroyed by projectiles fired by the aliens. Nishikado had introduced a novel element to the video game - an enemy that could return fire, and that could exercise a measure of intelligence in targeting the player's weapon.

Nishikado also demonstrated a degree of ingenuity in exploiting one of the limitations of the hardware. He found that the speed with which the alien spacecraft moved backwards and forwards across the screen was determined by the number of aliens present. The fewer aliens there were on screen, the faster they moved. Instead of trying to compensate for the inability of the processor to keep up with the demands placed upon it, he made it a feature of the game. It thus becomes more difficult to target and destroy the alien spacecraft as their numbers diminish.

The speed of the game is also matched by the tempo of the electronic soundtrack that accompanies it so that, as the spacecraft move faster, the tempo increases. The overall effect is to instil a sense of urgency in the player which grows stronger as the game progresses (I can remember playing this game in an amusement arcade in the late seventies and experiencing a level of anxiety verging on panic).

Players have a fixed number of lives at the start of the game, although they are awarded additional lives if they score enough points. Each alien spaceship destroyed increases the player's score. At arbitrary time intervals, a different kind of alien ship flies across the top of the screen at a much greater speed than the rest of the "fleet". Destroying one of these ships earns the player far more points than destroying a "normal" alien craft, although they are of course much more difficult to hit.

It is also necessary to ensure that no alien craft actually reach the bottom of the screen, because if they do it's game over. There is not much respite, either, when the player has destroyed the last alien craft in the current wave. The screen is immediately filled with a new batch of aliens. Worse still, each new group of aliens materialises just a little bit closer to the bottom of the screen than the previous group, giving the player less time to take out the bottom row of spacecraft to prevent the aliens from landing.

The laser cannon can be protected to some extent using the shields positioned at the bottom of the screen. The player can move the cannon under a shield in order to prevent it from being destroyed. The shields themselves can be broken down by enemy fire, however, so you can't hide forever. You will in any case need to emerge from cover in order to fire at the alien ships. A shield is also damaged if the player fires whilst the laser cannon is directly underneath it.

Movement of the cannon is achieved using either a simple joystick or by holding down left and right buttons (depending on the type of cabinet installed) whilst a separate button is used to fire. In most of the online simulations we have played, the left and right cursor buttons control the movement of the laser cannon, and the spacebar is used to fire the weapon.

Although the arcade version of the game could be played by two players, only one player could play at a time. The interactive nature of the game was thus primarily characterised as a contest between a human being and the machine. Competition with other players did of course exist, for the simple reason that the game not only allowed to player to see their accumulated score at all times, but also allowed the highest score to be recorded on the game machine.

Needless to say, recording the highest score was an achievement many players aspired to. Later versions of the game would also allow the player with the highest score to record their name on the machine (sadly, it was never my name up there in lights).

Most of the game's electronic components came from the USA. The central component was an Intel 8080 microprocessor, and the game's audio was generated by a Texas Instruments sound chip. Since generating colour images was somewhat beyond the limited capabilities of the game's circuitry, the graphics were initially monochrome only.

The arcade machines produced in the United States by Bally Manufacturing had strips of coloured cellophane overlaid on the screen to give the illusion of a coloured graphics display, a practice which was also later adopted by Taito in Japan.

Within two years, Taito had produced more than three hundred thousand arcade machines in Japan, with a further sixty thousand or so being produced in the United States. During the first few years of the game's existence, it reportedly generated revenues worldwide of over six hundred million US dollars per year. This kind of financial return on investment for a video game was unprecedented, and showed that, as an entertainment medium, video games could compete with the film industry in terms of profitability.

Atari were quick to realise the potential of the game, and in 1980 licensed it for several of their game consoles, starting with the Atari 2600. In so doing they became the first company to license another company's game for home consoles. As a result, they made a huge amount of money from sales of their home game consoles. In 1985, Taito licensed the game to Nintendo for their Nintendo Entertainment System (NES), but only for the Japanese market.

Space Invaders has inevitably spawned a number of sequels, remakes and imitators, and has undoubtedly been a major influence on generations of games that followed it. Updated versions can be found on many of today's game consoles, and numerous simulations of the original game can be found online.

A pretty good simulation can be found at http://www.freeinvaders.org. Like Pong before it, Space Invaders has become a part of popular culture, and has frequently been parodied or alluded to in various forms of entertainment, including television shows, theatre productions, and contemporary music. Pong had proved that video games could be both hugely popular and profitable. Space invaders showed the world just how profitable they could be.

_{This article was first published on the TechnologyUK.net website in January 2009.}

Multi-User Dungeon (MUD) - 1978

The term MUD (Multi-User Dungeon) can actually be applied to an entire category of (mostly) text-based role playing games (RPGs) that have emerged over the last few decades. The game we are primarily interested in here is sometimes referred to as MUD1, or Essex MUD, and is considered by many protagonists to be the original, and perhaps the best, multi-user dungeon. The origins of MUD actually go back somewhat further.

Stop playing the opening music for Star Wars! We're not talking about a long time ago in a galaxy far, far away. If we have to choose a place to start, the story probably begins with a single-player adventure game created by programmer and cave explorer William Crowther in 1976 called Colossal Cave Adventure. Crowther was apparently inspired by the Dungeons and Dragons fantasy role-playing game. Crowther based the game's environment on the real-world Mammoth Cave system in Kentucky, USA, which he had personally explored extensively.

At the time, Crowther worked as a programmer for Bolt, Beranek & Newman, a US high-tech company that had a major role in developing ARPANET, the forerunner of the Internet. The original game was written in the Fortran programming language, and ran on a Digital Equipment Corporation PDP-10 mainframe computer. The game was eventually ported to various other platforms, and a number of different versions of the game emerged.

In 1976 programmer Don Woods, who had come across Crowther's original version of the game by accident, e-mailed Crowther asking for permission to develop the game further. Crowther gave his blessing, and by the following year copies of Woods' enhanced version of the game were being distributed via the Internet. The game apparently inspired Ken and Roberta Williams to start their own gaming software company, On-Line Software. The company prospered, and later went on (as Sierra Entertainment) to produce a number of commercially successful adventure games, including King's Quest and Leisure Suit Larry.

It is probably the 1977 Crowther/Woods version of the game that is most often considered to be the definitive classic version, although various other versions have been written, including several written by Don Woods himself. It is quite difficult to describe a game of this nature to someone who has never played it.

Perhaps the best way to find out what it's all about is to play it for yourself. Several versions can be downloaded as DOS executables here. The versions we have tried will not run directly under a 64-bit version of Windows, but will run quite happily in DOSBox. The following series of screenshots are taken from Kevin Black's DOS version of the original game, as written by William Crowther and extended by Don Woods.

You probably get the general idea from the above screen shots as to how the game proceeds. The player enters short one- or two-word commands, and the game responds with some helpful (or sometimes not so helpful) text. Woods was an admirer of the work of J.R.R. Tolkien (the author of "The Hobbit" and "Lord of the Rings"), so expect to come across fantasy elements such as axe-wielding dwarves, magic bridges, elves, trolls, and so-on.

A number of "magic" words and phrases also exist within the game's vocabulary that will (for example) instantly transport you from one location to another if used at certain points in the game. In some cases, the action triggered by a vocabulary word or phrase will be randomly generated. The idea, generally, is to navigate your way through the game, collecting treasures and earning points while avoiding getting killed. Treasures can be used at different locations within the game for various purposes.

In 1977, a small group of students at the Massachusetts Institute of Technology (MIT) produced their own single-player adventure game, apparently inspired by Colossal Cave Adventure, called Zork. The program was written using the MIT Design Language (MDL), which was closely related to LISP, a language commonly used for artificial intelligence programs. Like Colossal Cave Adventure, Zork ran on a DEC PDP-10 mainframe computer.

Some of the game's creators went on to form the Massachusetts-based software company Infocom, which would produce a trilogy of Zork games that ran on all popular personal computers of the time, including the Commodore 64 and the Apple II. The games were released in 1980 (Zork I: The Great Underground Adventure), 1981 (Zork II: The Wizard of Frobozz), and 1982 (Zork III: The Dungeon Master). You can download playable versions of all three games on the Infocom website here.

The MIT version of Zork, which could be downloaded via the ARPANET, was the inspiration for the original MUD. In 1978, a student at Essex University called Roy Trubshaw started programming the first version of MUD on a DEC PDP-10 Mainframe computer installed at the university. The program was originally written in the MACRO-10 assembly language, although some time prior to 1980 Trubshaw re-wrote the code in the Basic Combined Programming Language (BCPL) in order to make it easier to maintain (BCPL was a forerunner of C).

Trubshaw was an avid fan of Zork, and derived the name MUD (which as mentioned previously stands for Multi-User Dungeon) from the name of an early Zork variant called Dungeon. Like the single-player games that preceded it, MUD is a text-based role-playing adventure game in which the player finds themselves in a fantasy world though which they must navigate using brief commands consisting of words or phrases. Unlike its predecessors, however, MUD allowed a number of players to participate in the game simultaneously and to interact with one another.

One of Trubshaw's design goals for the game was to create a database that would allow changes or additions to be made without having to re-compile the program code. In this task he was ably assisted by fellow student Richard Bartle. When Trubshaw graduated late in 1980, he left the further development and management of MUD in the hands of Bartle. That same year saw developments that enabled MUD to reach a wider audience.

Until 1980, the number of players was limited by the number of network connections available. The number of players who could potentially access the game increased dramatically when the university's network was connected to the ARPANET in 1980. The number increased again in 1983, when a guest account was set up to allow users of the UK's Joint Academic Network (JANET) to access the game. MUD had become the first multiplayer online role-playing adventure game. Access to the game was free at weekends, and between 0200 hours and 0800 hours GMT during the week.

Although access to MUD on Essex University's network was free of charge during the designated hours, it was also limited by the number of available connections, and was consequently over-subscribed. In 1984, MUD was licensed by Compunet, a UK-based network that catered primarily to Commodore 64 users. Compunet ran the game on their PDP-10 mainframe computer, providing access to the game for its users on a commercial basis. The service was discontinued when the PDP-10 was decommissioned in 1987.

By 1985, Bartle had developed the version of MUD that was to become known as MUD2. This version was licensed by Compuserve, a US-based Internet service provider, who also provided access to the game (under the name British Legends) on a commercial basis. In 1987, allegedly as a result of pressure from Compuserve, Bartle closed down the instance of MUD running on Essex University's network. Compuserve closed their own version of the game down in 1999, allegedly as part of a broader Y2K cleanup process.

Essex MUD (or MUD1) has spawned many variants and imitators, one of the most popular of which was a variant of the original MUD called MIST. Once Essex MUD was closed down in 1987, MIST was the only MUD variant still available on the university's network. MIST survived for a further four years by virtue of the fact that it ran from a separate account to MUD1, although it too met its demise when the PDP-10 mainframe that hosted it was replaced in 1991.

MUD's legacy can be seen today in many different forms. Thanks to an exponential increase in processing power and the widespread availability of high-speed internet access, a number of graphical multiplayer online role-playing adventure games have emerged. Such games were initially called simply graphical MUDs, but in the late 1990s the term Massively Multiplayer Online Role-Playing Games (MMORPGs) became the preferred term. Undoubtedly the best-known example is World of Warcraft. Gaming connoisseurs interested in playing MUD1 should check out Viktor Toth's British-Legends website here.

_{This article was first published on the TechnologyUK.net website in January 2009}

Pong - 1972

Pong was the first video arcade game from Atari, the company set up in 1972 by Nolan Bushnell and Ted Dabney in Sunnyvale, California. Bushnell's interest in computer games is believed to have been inspired by former MIT student Steve Russell, who introduced Bushnell, then an engineering student, to the Spacewar! computer game during his tenure at the University of Utah in the mid-1960s.

Bushnell and Dabney had subsequently designed the Computer Space arcade game, based on Spacewar!, for Nutting Associates. Bushnell's initial vision for Atari was to create game concepts that could then be licensed to other companies, presumably on the basis that these partner companies would bear the cost (and associated risk) of manufacturing arcade game units while Atari could take a cut of the profits with relatively little financial exposure. As often happens in life, things did not work out quite as Bushnell intended.

Atari's first major contract was with the Chicago-based Bally Manufacturing Corporation, who hired Atari to produce a driving game for them. Bushnell had hired Berkley graduate Alan Allcorn as an engineer, based on his background in computer science and electrical engineering, and despite Allcorn's complete lack of experience with computer game technology.

Legend has it that Bushnell asked Allcorn to write a simple tennis game as a training exercise, using a specification that was based on a tennis game written for the Magnavox Oddyssey game console by Magnavox creator Ralph H. Baer (Atari would later settle out of court a lawsuit filed against them by Magnavox for alleged infringement of Baer's patents). The result of Allcorn's efforts impressed Bushnell and Dabney so much that Bushnell decided to offer it to Bally Manufacturing in place of the promised driving game.

The game concept itself was deceptively simple. Each player controlled a rectangular "paddle" that could be moved up and down at one end of the screen. The "ball" consisted of a small square dot that moved from one side of the screen to the other at fixed speed. The idea was for each player to prevent the ball from getting past their own paddle, and score points by getting it to go past their opponent's paddle. The points accrued by each player were displayed at the top of the screen.

Allcorn improved on the original game specification, which he apparently felt was too boring, by changing the angle at which the ball was returned depending on where exactly the ball made contact with the paddle. If the ball struck the paddle in the centre, it would be returned at the same angle at which it made contact. As the point of contact moved away from the centre and towards the edge of the paddle, however, the angle of return was increased. The speed of return also increased steadily, being reset to its original value only after one player or the other had failed to return the ball.

At the request of Bushnell, Allcorn subsequently added sound effects to simulate the sound of the ball striking the bat. Initially unsure of exactly how to achieve this, Allcorn experimented with the electronic component used to generate the game's electronic timing signals and found that it could also be used to generate various audio tones. A cheap Hitachi monochrome television was purchased as the game's display unit, and mounted inside a wooden cabinet.

The cabinet also housed the necessary game electronics. In order to test the marketability of the game, it was decided to install a prototype at a local bar called Andy Capp's Tavern run by one of Atari's existing customers, Bill Gattis. This was in September 1972. At the time, Atari's bread and butter work consisted of the supply, repair and maintenance of pinball machines installed in local bars and restaurants.

The initial reaction of customers in Andy Capp's Tavern to the new game was highly favourable, and the game's popularity grew rapidly. Within a week or so of the installation at Andy Capp's, Bushnell undertook a business trip to Chicago to try to sell the game concept to Bally Manufacturing. There are conflicting accounts of how these negotiations proceeded, but the end result was that Bally turned the game down for one reason or another. Meanwhile Atari had received a call from Bill Gattis saying that the game was behaving erratically, and Alan Allcorn was sent out to fix it.

On opening the game cabinet, Allcorn found the problem to be that the coin receptacle (which had been improvised using an upturned plastic milk container) was overflowing. This was an almost unprecedented turn of events, but highlighted just how commercially successful the game could be. Bushnell concluded that his failure to sell the idea to Bally Manufacturing was actually a good thing under the circumstances, and decided that Atari should manufacture and distribute the game units themselves.

Despite the reservations of both Dabney and Allcorn, and initial difficulties in finding a financial backer, Atari duly started to manufacture Pong arcade game units. The first dozen units were installed at various locations around southern California. The game's reputation quickly spread, and revenue from the installed units exceeded expectations. Subsequent interest in the game led to more orders, and by the end of 1973 Atari had overcome various teething problems and obtained sufficient funding to expand their manufacturing operation. They were soon shipping game units to destinations both within the United States and overseas.

By the end of 1974, it is estimated that Atari had achieved sales valued at over three million dollars. The total number of Pong consoles eventually produced is believed to exceed one hundred thousand, although only about a third of these were produced by Atari. The company initially failed to apply for a patent for the game's technology, leaving the door open for its competitors to produce Pong clones.

Atari responded by producing sequels that added new features to the original game, and began working on a home console version. The home console was first proposed in 1974 by Atari engineer Harold Lee, who worked together with Alan Allcorn to produce the initial designs. They were later joined by Atari engineer Bob Brown in the construction of a prototype.

Atari managed to attract the attention of the Sporting Goods department of the Sears, Roebuck & Co. department store chain, and eventually secured a contract for one hundred and fifty thousand units. The units went on sale in Sears' retail stores during the 1975 Christmas season, bearing the Sears Tele-Games logo. The Christmas sales campaign was a success, and in the following year Atari released a version of the console bearing its own brand name.

Once again, Atari's competitors cashed in on the popularity and commercial success of Pong, producing their own versions of the Atari home game console. Some of these competitors made their first foray into the games market with clones of Atari's console version of Pong, one notable example being Nintendo. Nevertheless, Atari continued to prosper and Nolan Bushnell sold the company to Warner Communications in 1976 for an estimated thirty million dollars.

That same year Atari released a game called Breakout, which was originally conceptualised by Bushnell as a single-player version of Pong. Alan Allcorn, as project manager, assigned Steve Jobs to design a prototype circuit board. Jobs was a college dropout who had originally been hired by Atari in 1974 as a technician. Jobs subsequently enlisted the help of electronics wizard Steve Wozniak, whom he had met in high school. Jobs and Wozniak later became co-founders of Apple Computers.

Although opinions differ on just how much of an influence Pong has had on the history of computer gaming, many pundits assert that it was the game that kick-started the video game industry. It has certainly earned its place in the gaming hall of fame, and its enduring success is in no small part attributable to its essential simplicity. Anyone could play Pong, even if they had little idea of how the technology worked, or had never previously played a computer game.

Perhaps more to the point from a commercial point of view, people were willing to part with their hard-earned cash in order to play. It has even been claimed that Pong was the first example of social gaming, since it was essentially a two-player game (later versions would allow four players to play simultaneously). Pong has even found its place in popular culture, having been parodied or alluded to in various comedy sketches, advertising campaigns, and artistic works. You can play a number of online versions of the game here.

_{This article was first published on the TechnologyUK.net website in January 2009}

Spacewar! - 1962

The history of computer gaming goes back to the early days of mainframe computing, decades before personal computers were available, and before they were even imagined by any but a small number of visionaries. Sadly, documentary records for many of these early games have been lost forever. A notable exception, and one of the earliest computer games ever written, was Spacewar! developed by MIT students Martin Graetz, Wayne Wiitanen and Alan Kotok together with MIT employee Steve Russell. Spacewar!, completed in 1962, was written for a Digital Equipment Corporation (DEC) PDP-1 minicomputer whose official purpose was the compilation of statistics.

Although possibly the first multiplayer computer game, Spacewar! was not the first to exploit the graphics capabilities of a digital computer. One well-documented example is OXO, a game of Noughts and Crosses (or Tic-tac-toe, to give it its American name). OXO was developed by Alexander Douglas, a computer science professor at Cambridge University, in 1952.

Another example, Tennis for Two, was created by US physicist William Higginbotham at the Brookhaven National Laboratory in New York in 1958. These early games, however, used discrete analogue electronics to implement the game routines rather than software. Spacewar! is probably the earliest example, for which documentation still exists, of a graphical computer game implemented as a computer program.

The original concept for Spacewar! was the brainchild of Massachusetts Institute of Technology (MIT) student Steve Russell, and was apparently inspired by the work of the legendary science fiction author E.E. "Doc" Smith. Russell, together with several other students and MIT personnel, developed the program in order to demonstrate the graphics capabilities of the PDP-1.

Although Russell is often given credit for writing the program, it was essentially a team effort. The sine and cosine routines were contributed by Alan Kotok, who in turn obtained the routines from the Digital Equipment Corporation (DEC). DEC would later include the Spacewar! game when delivering new PDP-1 minicomputers to customers, both to showcase the machine's graphic capabilities and as a diagnostic tool.

The original version of the game features two spaceships, each controlled by one of the players. Each player must try to maneuver their spaceship into a position from which they can fire their weapon and destroy their opponent's spaceship. The controls allowed the player to rotate their ship, either clockwise or counter-clockwise, and fire thrusters to send the ship on a particular trajectory. Each ship has limited amounts of both ammunition and fuel.

The original controls consisted of a number of test switches on the front panel of the PDP-1 (four per player). This soon proved unsatisfactory as the switches, which were not designed for playing games, were quickly worn out due to excessive wear and tear. A playable Java emulation of the original PDP-1 code can be seen here.

A variety of more practical input devices were subsequently developed for the game and its numerous variants, and additional features were added to the game itself. The background starfield was originally generated as a random pattern, but Peter Sansom developed a new background based on actual star charts that scrolled slowly across the screen.

A somewhat larger star was added to the centre of the screen, creating a gravitational field that both ships had to try and avoid being pulled into (although for some reason the projectiles fired by the ship's weapons remained unaffected by the star's gravitational field). The code for the emulating the effects of gravity was added by Dan Edwards.

It is probably worth noting that the gameplay overall, including the maneuvering of the two spaceships, generally obeys the laws of Newtonian physics. A notable exception is the hyperspace feature (written by Russell) that allows a player to make a random "jump" to another point on the screen when threatened with imminent danger.

There is however a risk factor associated with such a maneuver, since there is no guarantee that the spaceship will not re-enter normal space in close proximity to the star, or directly in the path of an enemy projectile. There is also a chance of the spaceship exploding after using the hyperspace feature, which increases each time the feature is used. Further enhancements would be added to the game in due course.

Spacewar! became hugely popular, and was ported to a number of other computer systems. Many games later emerged that were either variations on the original Spacewar! or took their inspiration directly from some or all of its features. Several arcade versions of the game were created including the Galaxy Game, which was programmed by Bill Pitts and Hugh Tuck and installed in the Coffee House of the Tresidder Union at Stanford University in 1971.

The Galaxy Game is thought to be one of the earliest coin operated video games. Later the same year, Nutting Associates produced a commercial video arcade game based on Spacewars! called Computer Space. The game was created by Nolan Bushnell and Ted Dabney. Bushnell, an engineering student, had been introduced to game programming (and Spacewar!) by Steve Russell. Bushnell and Dabney went on to found the video game company Atari.

A networked version of the game, called Orbitwar and created by games programmer Silas Warner, appeared in 1974. In 1977, the California-based company Cinematronix Incorporated introduced the similarly-named Space Wars, developed by MIT graduate Larry Rosenthal and probably the most commercially successful of the many Spacewar! clones. In the following year Atari produced their own version, called Space War, for the Atari 2600 game console.

A (more or less) original version of Spacewar! still runs on the only PDP-1 computer known to be still operational, which is housed at the Computer History Museum in Mountain View, California. Another very good online simulation of the original game, which gives you a good idea of what the game would have looked like on the original CRT display device, can be found here.

_{This article was first published on the TechnologyUK.net website in January 2009}