~8 minute readThe History of Zork -- First in a Series
In the beginning, back in the 1960's, DEC (Digital Equipment Corporation) created the PDP-10, a medium-sized computer. The "10", as it was called, became popular at many research installations, and a great deal of software was written for it, some of which is still far in advance of systems on more modern machines. At MIT's Artificial Intelligence Lab, an operating system called ITS (Incompatible Timesharing System) was written for the 10. ITS was designed to make software development easy. The designers of the system assumed that it would have a small, knowledgeable, friendly group of users, so they did not include any security features.
Around 1970, the ARPAnet was invented. ARPAnet made it possible for researchers all over the country (indeed, all over the world) to communicate with each other, and to use each other's machines. In those halcyon days, access was unrestricted; you could get on from any machine connected to the net, or by knowing an appropriate phone number. Budding hackers from around the country soon discovered that this made a wonderful playground. They also discovered that there were some computers at MIT with some neat stuff on them and no security — anyone who could connect to the machines could log in.
Also around 1970, a language called MUDDLE (later renamed MDL) was developed as a successor to LISP. It never succeeded in fully replacing LISP, but it developed a loyal user community of its own, primarily at MIT's Project MAC (now called the Laboratory for Computer Science) and especially in the Dynamic Modelling Group (later the Programming Technology Division). The Dynamic Modelling Group (DM), in addition to its other accomplishments, was responsible for some famous games. The first of these was a multi-player graphics game called Maze, in which players wandered around a maze shooting each other. Each user's screen showed the view of the maze that his or her computerized alter-ego saw, updated in real time. Dave Lebling was among those chiefly responsible (to blame?) for the existence of the game.
The next game of note was Trivia (who says research labs aren't ahead of their time?), an ongoing "can you top this" contest for the truly crazed. Trivia, unlike Maze, could be played by network users, and achieved wide popularity on the ARPAnet. Marc Blank wrote the second version, and I maintained/hacked it; it was actually a legitimate test of a database system the group used for a research project.
In early 1977, Adventure swept the ARPAnet. Willie Crowther was the original author, but Don Woods greatly expanded the game and unleashed it on an unsuspecting network. When Adventure arrived at MIT, the reaction was typical: after everybody spent a lot of time doing nothing but solving the game (it's estimated that Adventure set the entire computer industry back two weeks), the true lunatics began to think about how they could do it better. Adventure was written in FORTRAN, after all, so it couldn't be very smart. It accepted only two-word commands, it was obviously hard to change, and the problems were sometimes not everything one could desire. (I was present when Bruce Daniels, one of the DM'ers, figured out how to get the last point in Adventure by examining the game with a machine-language debugger. There was no other way to do it.)
By late May, Adventure had been solved, and various DM'ers were looking for ways to have fun. Marc Blank was enjoying a respite from medical school; I had just finished my master's degree; Bruce Daniels was getting bored with his Ph.D. topic; and Dave Lebling was heartily sick of Morse code. Dave wrote (in MUDDLE) a command parser that was almost as smart as Adventure's; Marc and I, who were both in the habit of hacking all night, took advantage of this to write a prototype four-room game. It has long since vanished. There was a band, a bandbox, a peanut room (the band was outside the door, playing "Hail to the Chief"), and a "chamber filled with deadlines." Dave played and tested the game, saw that it was pretty awful, and left to spend two weeks basking in the sun.
Marc, Bruce, and I sat down to write a real game. We began by drawing some maps, inventing some problems, and arguing a lot about how to make things work. Bruce still had some thoughts of graduating, thus preferring design to implementation, so Marc and I spent the rest of Dave's vacation in the terminal room implementing the first version of Zork. Zork, by the way, was never really named. "Zork" was a nonsense word floating around; it was usually a verb, as in "zork the fweep," and may have been derived from "zorch." ("Zorch" is another nonsense word implying total destruction.) We tended to name our programs with the word "zork" until they were ready to be installed on the system.
By the time Dave got back, there was a (more-or-less) working game. It probably wasn't as big as Adventure, and was certainly less than half the size of the final version, but it had the thief, the cyclops, the troll, the reservoir and dam, the house, part of the forest, the glacier, the maze, and a bunch of other stuff. The problems were not as interesting as those that came later: it took time for people to learn how to write good problems, and the early parsers wouldn't support complicated solutions anyway. What we had done right was all in the "substratum." There was a well-defined (and easily-changed) theory governing interactions among objects, verbs, and rooms. It was easy to drop in new parsers, which happened frequently, since everyone and his uncle tried his hand at writing a parser (Marc finally became obsessed with it, and wrote the last 40 or 50 of them himself). And it was easy to add new rooms, objects, and creatures (I won't discuss the difficulty of adding new concepts yet).
Zork, like Adventure, survived only because it was played by people outside the small community that developed it. In the case of Adventure, this was possible because it was written in FORTRAN and could run on practically any machine. Zork was written in MUDDLE, which ran on only some PDP-10s. Its user community was the group of "net randoms" that infested the MIT systems; remember that we had no security at all at this time. DM had developed an active community largely because of Trivia. Since Trivia was pretty dead by the time Zork came along, there weren't many other things for the randoms to do, so they hung around waiting for the next game. Early players of Zork ranged from John McCarthy, the inventor of LISP (we actually have a copy of the connectivity matrix that McCarthy used instead of a map), to twelve-year-olds from Northern Virginia. No one ever officially announced Zork: people would log in to DM, see that someone was running a program named Zork, and get interested. They would then "snoop" on the console of the person running Zork, and see that it was an Adventure-like game. From there, it only took a little more effort to find out how to start it up. For a long time, the magic incantation was ":MARC;ZORK"; people who had never heard of ITS, DM, or PDP-10s somehow heard that if they got to something called "host 70" on the ARPAnet, logged in, and typed the magic word, they could play a game.
Although Zork in June 1977 was infinitely more primitive than, say, Zork I, it still had pretty much the same flavor. The Flathead family was represented, in the person of Lord Dimwit Flathead the Excessive, ruler of the Great Underground Empire; and the official currency was the zorkmid. Bruce was responsible for the purplish prose where these were first mentioned.
Many of the details of the GUE were whimsical (if not silly), but we weren't completely immune to reality. In those days, if one wandered around in the dark area of the dungeon, one fell into a bottomless pit. Many users pointed out that a bottomless pit in an attic should be noticeable from the ground floor of the house. Dave came up with the notion of grues, and he wrote their description. From the beginning (or almost the beginning, anyway), the living room had a copy of "US News & Dungeon Report," describing recent changes in the game. All changes were credited to some group of implementers, but not necessarily to those actually responsible: one of the issues describe Bruce working for weeks to fill in all the bottomless pits in the dungeon, thus forcing packs of grues to roam around.
The first major addition to the game, done in June 1977, was the river section, designed and implemented by Marc. It survives largely unchanged in Zork I, but illustrates very well the problems of building reality. There were minor problems of consistency — some parts of the river were sunlit (and even reachable from outside), but others were dark. The major problem resulted from the new concept Marc introduced: vehicles. In the original game, there were rooms, objects, and a player; the player always existed in some room. Vehicles were objects that became, in effect, mobile rooms. This required changes in the (always delicate) interactions among verbs, objects, and rooms (we had to have some way of making "walk" do something reasonable when the player was in the boat). In addition, ever-resourceful Zorkers tried to use the boat anywhere they thought they could. The code for the boat itself was not designed to function outside the river section, but nothing kept the player from carrying the deflated boat to the reservoir and trying to sail across. Eventually the boat was allowed in the reservoir, but the general problem always remained: anything that changes the world you're modelling changes practically everything in the world you're modelling.
Although Zork was only a month old, it could already surprise its authors. The boat, due to the details of its implementation, turned into a "bag of holding": players could put practically anything into it and carry it around, even if the weight of the contents far exceeded what a player was allowed to carry. The boat was two separate objects: the "inflated boat" object contained the objects, but the player carried the "deflated boat" object around. We knew nothing about this: someone finally reported it to us as a bug. As far as I know, the bug is still there.
[Coming up in the next issue: Zork Assumes an Alias.]
This article appeared in
New Zork Times, The
Jan-Mar 1985
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