The Z-machine is a

virtual machine In computing, a virtual machine (VM) is the virtualization/ emulation of a computer system. Virtual machines are based on computer architectures and provide functionality of a physical computer. Their implementations may involve specialized h ...

that was developed by Joel Berez and Marc Blank in 1979 and used by

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 o ...

for its text adventure games. Infocom compiled game code to files containing Z-machine instructions (called story files or Z-code files) and could therefore port its text adventures to a new platform simply by writing a Z-machine implementation for that platform. With the large number of incompatible home computer systems in use at the time, this was an important advantage over using native code or developing a compiler for each system.

History

The "Z" of Z-machine stands for

Zork ''Zork'' is a text-based adventure game first released in 1977 by developers Tim Anderson, Marc Blank, Bruce Daniels, and Dave Lebling for the PDP-10 mainframe computer. The original developers and others, as the company Infocom, expanded a ...

, Infocom's first adventure game. Z-code files usually have names ending in .z1, .z2, .z3, .z4, .z5, .z6, .z7, or .z8, where the number is the version number of the Z-machine on which the file is intended to be run, as given by the first

byte The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable uni ...

of the story file. This is a modern convention, however. Infocom itself used extensions of .dat (Data) and .zip (ZIP = Z-machine Interpreter Program), but the latter clashed with the widespread use of .zip for PKZIP-compatible archive files starting in the 1990s, after

Activision Activision Publishing, Inc. is an American video game publisher based in Santa Monica, California. It serves as the publishing business for its parent company, Activision Blizzard, and consists of several subsidiary studios. Activision is one ...

closed Infocom. Infocom produced six versions of the Z-machine. Files using versions 1 and 2 are very rare. Only two version 1 files are known to have been released by Infocom and only two of version 2. Version 3 covers the majority of Infocom's released games. Later versions had more capabilities, culminating in some graphic support in version 6. The

compiler In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs tha ...

(called Zilch) that Infocom used to produce its story files has never been released, although documentation of the

language Language is a structured system of communication. The structure of a language is its grammar and the free components are its vocabulary. Languages are the primary means by which humans communicate, and may be conveyed through a variety of ...

used (, a

Lisp A lisp is a speech impairment in which a person misarticulates sibilants (, , , , , , , ). These misarticulations often result in unclear speech. Types * A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lispin ...

-family language similar to MDL) still exists, and an open-source replacement has been written. After

Mediagenic Activision Publishing, Inc. is an American video game publisher based in Santa Monica, California. It serves as the publishing business for its parent company, Activision Blizzard, and consists of several subsidiary studios. Activision is one o ...

moved Infocom to California in 1989, ''

Computer Gaming World ''Computer Gaming World'' (CGW) was an American computer game magazine published between 1981 and 2006. One of the few magazines of the era to survive the video game crash of 1983, it was sold to Ziff Davis in 1993. It expanded greatly throug ...

'' stated that "ZIL ... is functionally dead", and reported rumors of a "completely new parser that may never be used". In May 1993, Graham Nelson released the first version of his

Inform Inform is a programming language and design system for interactive fiction originally created in 1993 by Graham Nelson. Inform can generate programs designed for the Z-code or Glulx virtual machines. Versions 1 through 5 were released betwe ...

compiler, which also generates Z-machine story files as its output, even though the Inform source language is quite different from ZIL. Inform has become popular in the

interactive fiction '' Interactive fiction, often abbreviated IF, is software simulating environments in which players use text commands to control characters and influence the environment. Works in this form can be understood as literary narratives, either in the ...

community. A large proportion of interactive fiction is in the form of Z-machine story files. Demand for the ability to create larger game files led Nelson to specify versions 7 and 8 of the Z-machine, though version 7 is rarely used. Because of the way addresses are handled, a version 3 story file can be up to 128K in length, a version 5 story can be up to 256K in length, and a version 8 story can be up to 512k in length. Though these sizes may seem small by today's computing standards, for text-only adventures, these are large enough for elaborate games. During the 1990s, Nelson drew up a Z-Machine Standard based on detailed studies of the existing Infocom files.

ZIL (Zork Implementation Language)

Here's what the definition of Zork I's brass lantern looks like:

History

ZIL (Zork Implementation Language)

Interpreters

See also

References

External links