Infocom

Infocom was an American software company based in Cambridge, Massachusetts, that produced numerous works of interactive fiction. They also produced a business application, a relational database called Cornerstone.

Infocom was founded on June 22, 1979, by staff and students of Massachusetts Institute of Technology, and lasted as an independent company until 1986, when it was bought by Activision. Activision shut down the Infocom division in 1989, although they released some titles in the 1990s under the Infocom Zork brand. Activision abandoned the Infocom trademark in 2002.

Infocom games are text adventures where users direct the action by entering short strings of words to give commands when prompted. Generally the program will respond by describing the results of the action, often the contents of a room if the player has moved within the virtual world. The user reads this information, decides what to do, and enters another short series of words. Examples include "go west" or "take flashlight".

Infocom games were written using a programming language called ZIL (Zork Implementation Language), itself derived directly from MDL (programming language), that compiled into a byte code able to run on a standardized virtual machine called the Z-machine. As the games were text based and used variants of the same Z-machine interpreter, the interpreter had to be ported to new computer architectures only once per architecture, rather than once per game. Each game file included a sophisticated parser which allowed the user to type complex instructions to the game. Unlike earlier works of interactive fiction which only understood commands of the form 'verb noun', Infocom's parser could understand a wider variety of sentences. For instance one might type "open the large door, then go west", or "go to festeron".

With the Z-machine, Infocom was able to release most of their games for most popular home computers simultaneously: Apple II, Atari 8-bit family, IBM PC compatibles, Amstrad CPC/PCW (one disc worked on both machines), Commodore 64, Commodore Plus/4, Commodore 128, Kaypro CP/M, Texas Instruments TI-99/4A, Macintosh, Atari ST, Amiga, TRS-80, and TRS-80 Color Computer.