The Z-machine is a virtual machine that was developed by Joel Berez and Marc Blank in 1979 and used by Infocom for its text adventure games. In Computer science, a virtual machine (VM is a Software implementation of a machine (computer that executes programs like a real machine Marc Blank is an American Computer game designer and Game programmer. Infocom was a Software company, based in Cambridge Massachusetts, that produced numerous works of Interactive fiction. Infocom compiled game code to files containing Z-machine instructions (called story files, or Z-code files), and could therefore port all 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 some compiler for each system).

The "Z" of Z-machine stands for Zork, Infocom's first adventure game. Zork was one of the first Interactive fiction Computer games and an early descendant of Colossal Cave Adventure. 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 of the story file. A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science. This is a modern convention, however. Infocom itself used extensions of . dat (Data) and . zip (ZIP = Z-machine Interpreter Program), but the latter clashes with the present widespread use of . zip for PKZIP-compatible archive files (which did not exist yet during the time Infocom was active). The ZIP File format is a Data compression and archival format. 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 vast majority of Infocom's released games. The later versions had more capabilities, culminating in some graphic support in version 6.

The compiler (called Zilch) which Infocom used to produce its story files has never been released, although documentation of the language used (called ZIL, for Zork Implementation Language) is still in existence. A compiler is a Computer program (or set of programs that translates text written in a computer language (the source language) into another But in May 1993, Graham Nelson released the first version of his Inform compiler, which also generates Z-machine story files as its output, even though the Inform source language is quite different from ZIL. Graham A Nelson (born 1968 is a British mathematician poet and the creator of the Inform design system for creating Interactive fiction (IF games Inform is a Programming language and design system for Interactive fiction originally created in 1993 by Graham Nelson. Most files produced by Inform are version 5.

Inform has since become very popular in the interactive fiction community and, as a consequence, a large proportion of the interactive fiction now produced is in the form of Z-machine story files. Demand for the ability to create larger game files led Graham Nelson to specify versions 7 and 8 of the Z-machine, though version 7 is very rarely used. Graham A Nelson (born 1968 is a British mathematician poet and the creator of the Inform design system for creating Interactive fiction (IF games 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 very elaborate games.

During the 1990s, Graham Nelson drew up a Z-machine standard, based on detailed studies of the existing Infocom files. Graham A Nelson (born 1968 is a British mathematician poet and the creator of the Inform design system for creating Interactive fiction (IF games

Interpreters

Interpreters for Z-code files are available on such a wide variety of platforms - for example, on various old machines (such as the Apple II, TRS-80 and Sinclair), portable machines (such as Palm OS devices and the Nintendo Game Boy) and most modern platforms, showing that it is a very portable language. In Computer science, an interpreter normally means a Computer program that executes, i TRS-80 was Tandy Corporation 's desktop Microcomputer model line sold through Tandy's Radio Shack stores in the late 1970s and early Sinclair Research Ltd is a consumer electronics company founded by Sir Clive Sinclair in Cambridge, England (originally as Sinclair Radionics in 1961 to Palm OS (also known as Garnet OS) is an embedded Operating system initially developed by U The is a handheld video game console developed and manufactured by Nintendo.

Popular interpreters include Nitfol and Frotz. Nitfol makes use of the Glk API, and supports versions 1 through 8 of the Z-machine, including the version 6 graphical Z-machine. GLK is a portable API created by Andrew Plotkin for use by programs with a text interface; these programs mostly include Interactive fiction Save files are stored in the standard Quetzal save format. Quetzal is a standardised file format for the saved state of Z-machine games invented by Martin Frost. Binary files are currently available for several different operating systems, including Macintosh, Linux, MS-DOS, and Windows. In Computing, an executable (file causes a computer "to perform indicated tasks according to encoded instructions," as opposed to a file that only contains An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination Macintosh, commonly nicknamed Mac is a Brand name which covers several lines of Personal computers designed developed and marketed by Apple Inc Linux (commonly pronounced ˈlɪnəks MS-DOS (short for M icro' s' oft D isk O perating S ystem is an Operating system commercialized by Microsoft. Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft.

Frotz

Frotz is a Z-machine implementation: an adventure game engine for playing the Infocom's text adventures, as well as more recent games released by others. An adventure game is a type of Video game characterized by investigation exploration puzzle-solving, interaction with game characters and a focus on Narrative

Frotz is perhaps the most well-known and popular Z-machine implementation available. Its advantages over other Z-machine interpreters are twofold: firstly, though it was not the first non-Infocom interpreter to be released, it was one of the early ones -- its initial release by Stefan Jokisch was in 1995. Secondly, because the program is written in highly portable C, it has been possible to port the original DOS version to most modern computer formats, including not only Unix and Windows but even palmtops and mobile phones. See also Software portability In Computer science, porting is the process of adapting software so that an executable program can be created tags please moot on the talk page first! --> In Computing, C is a general-purpose cross-platform block structured Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer Microsoft Windows is a series of Software Operating systems and Graphical user interfaces produced by Microsoft. Various extensions have since been added, such as sound effects and graphics. For the album by The Jam see Sound Affects. Sound effects or audio effects are artificially created or enhanced Sounds Graphics (from Greek grc [[wiktγραφικός γραφικός]] see -graphy) are Visual presentations on some surface such as a wall

In 2002, the Frotz core codebase was picked up by David Griffith, who continues to develop it. The codebase was then distinctly split between the virtual machine and the user interface portions such that the virtual machine became entirely independent from any user interface. In Computer science, a virtual machine (VM is a Software implementation of a machine (computer that executes programs like a real machine The user interface (or Human Computer Interface) is the aggregate of means by which people&mdash the users '&mdash interact with the System This allowed some clever programmers to create some of the stranger ports of Frotz. One of the strangest is also one of the simplest: an instant messenger bot is wrapped around a version of Frotz with the bare minimum of IO functionality creating a bot with which one can play most Z-machine games using an instant messenger. Internet bots, also known as web robots, WWW robots or simply bots, are software applications that run automated tasks over the Internet In Computing, input/output, or I/O, refers to the communication between an Information processing system (such as a Computer) and the outside

Other utilities

ZorkTools is a collection of utility programs which provide capabilities not normally available for Z-code story files, such as listing all objects or vocabulary words. [1]

See also

• Glulx - a similar virtual-machine to Z-machine
• SCUMM - Script Creation Utility for Maniac Mansion by LucasArts, a graphical system similar to Z-machine

External links

• The Z-Machine standards document
• Learning ZIL (PDF) is the Infocom ZIL manual, dated 1989. Glulx is a 32-bit portable Virtual machine intended for writing and playing Interactive fiction. SCUMM ( Script Creation Utility for Maniac Mansion) is a scripting language developed at LucasArts (known at the time as Lucasfilm Games to ease development Maniac Mansion is a graphical Adventure game originally released in 1987 by Lucasfilm Games (now known as LucasArts) LucasArts Entertainment Company LLC is an American Video game developer and publisher.
• Interpreters for numerous platforms
• vbccz is a C compiler targeting the Z-machine. tags please moot on the talk page first! --> In Computing, C is a general-purpose cross-platform block structured
• How to Fit a Large Program Into a Small Machine describes the creation and design of the Z-machine.
• Frotz home page. The homepage for the Frotz core and the Unix and dumb versions. Contains links to all the ports the author is aware of.