In the late 1980s and early 90s many people sought to decode and emulate the Infocom story file format, and these efforts culminated in a set of largely working tools to disassemble story files (txd), extract text from them (Infodump), play them (InfoTaskForce and Zip) and create them (Inform). By the mid-1990s, the format was well understood, but poorly documented, at a time when an increasing number of tools were being written to work with it. In 1996, a committee of interested parties compiled the first draft of a Standard (0.2): the presently accepted Standard is 1.0, dating from May to September 1997. The format is regarded as being mature and stable. Relatively minor improvements, mainly concerning the Version 6 Z-Machine, have been made. It's generally felt that it would be inappropriate to radically restructure the Z-Machine with, for instance, a 32-bit architecture because (a) there are grave technical difficulties with this, and (b) the Glulx virtual machine is already a solution to this problem. The Standard is discussed and maintained by the Z-Machine Mailing List, to which all interpreter-writers will probably wish to belong. There is no formal standards committee, and instead all are invited to comment; decisions are taken by general consensus as far as possible. Related to the Standard, but not a part of it, are three formats for resources generated and used by the Z-Machine. Interpreter-writers are urged to use these standards, too.
See also Glulx
Z-Machine Standards Document 1.1 (9th revision, May 2006; errors corrected February 2014)
Link
The web edition of the current standard. This existed as a 1.1 proposal document for many years; it has now been integrated into the main text.
Z-Machine Standards Document 1.0 (May 1997; errors corrected February 2014)
Link
The first released version of the standard.
Quetzal (Version 1.4, 971103)
Link
A standard for saved game files. Adherence to Quetzal is enormously helpful for players, as it allows games to be saved on one interpreter (say on a person's desktop machine) and resumed on another (say on a personal organiser on the train). Since there is no argument about what information needs to be saved, there is no real reason not to observe this standard.
Blorb
Link
A standard package to hold resources needed by the story file in play (graphics, sound effects, etc.), one of which can be the story file itself, so that a multimedia work can be distributed as a single Blorb file. Even purely textual interpreters on platforms which could not manage graphics can benefit from supporting Blorb: the only absolute requirement is that an interpreter should be able to extract the Z-code part of a Blorb file and play it (ignoring all the other resources present if it chooses), and this is easily coded up.
The Treaty of Babel
Link
A standard for bibliographic information for interactive fiction games. This enables IF interpreters and web services to catalog and display metadata (title, author, and so on) in a consistent way. The Babel plan has been adopted by most major IF development systems.
Z-machine directory at the IF Archive
Link
Zipped PDF (280303) Peer Schaefer
Link (500KB)
Z-Machine Standard 1.0, with Standard 1.1 version 7, Blorb 1.1 and Quetzal 1.3b appended, in Portable Document Format.
Last updated 25 February 2014.
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This page was originally managed by Graham Nelson (graham@gnelson.demon.co.uk) assisted by C Knight.