Quetzal file format
Encyclopedia
Quetzal is a standardised file format for the saved state of Z-machine
games, invented by Martin Frost. Prior to the introduction of Quetzal, each Z-machine interpreter saved games in its own format; Quetzal enabled players to begin a game on one architecture (for example, a pocket computer) and end it on another. Use of the format is strongly recommended in Graham Nelson
's Z-machine standards document, but not obligatory. Most modern Z-machines have the ability to save Quetzal files.
The files are IFF
files with a FORM of "IFZS" (presumably standing for "interactive fiction
Z-machine save"), although the saved files are commonly given an extension of ".sav": less commonly sighted are "quz" and "qtz". Despite the reference to the Z-machine in the FORM code, the format has proved flexible enough to be adapted for at least one alternative architecture, Glulx
.
The magic-number reading of the files are often shown as:
The format's name is a backronym
for "Quetzal Unifies Efficiently The Z-Machine Archive Language".
Version 1.3b, which is widely available, contains a bug later corrected in version 1.4: after a save instruction, the Z-machine requires that a success code is saved in a particular place (which differs depending on the version). Versions of the Quetzal standard before 1.4 have reference only to the instruction after the save, which complicates finding the correct place to put the success code.
Z-machine
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. Infocom compiled game code to files containing Z-machine instructions , and could therefore port all its text adventures to a new platform simply by writing a...
games, invented by Martin Frost. Prior to the introduction of Quetzal, each Z-machine interpreter saved games in its own format; Quetzal enabled players to begin a game on one architecture (for example, a pocket computer) and end it on another. Use of the format is strongly recommended in Graham Nelson
Graham Nelson
Graham A. Nelson is a British mathematician and poet and the creator of the Inform design system for creating interactive fiction games. He has also authored several IF games, including the acclaimed Curses and Jigsaw , using the experience of writing Curses in particular to expand the range of...
's Z-machine standards document, but not obligatory. Most modern Z-machines have the ability to save Quetzal files.
The files are IFF
Interchange File Format
Interchange File Format , is a generic container file format originally introduced by the Electronic Arts company in 1985 in order to ease transfer of data between software produced by different companies....
files with a FORM of "IFZS" (presumably standing for "interactive fiction
Interactive fiction
Interactive fiction, often abbreviated IF, describes 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 and as video games. In common usage, the term refers to text...
Z-machine save"), although the saved files are commonly given an extension of ".sav": less commonly sighted are "quz" and "qtz". Despite the reference to the Z-machine in the FORM code, the format has proved flexible enough to be adapted for at least one alternative architecture, Glulx
Glulx
Glulx is a 32-bit portable virtual machine intended for writing and playing interactive fiction. It was designed by Andrew Plotkin to relieve some of the restrictions in the venerable Z-machine format...
.
The magic-number reading of the files are often shown as:
'IFF data, Z-machine or Glulx saved game file (Quetzal)'
The format's name is a backronym
Backronym
A backronym or bacronym is a phrase constructed purposely, such that an acronym can be formed to a specific desired word. Backronyms may be invented with serious or humorous intent, or may be a type of false or folk etymology....
for "Quetzal Unifies Efficiently The Z-Machine Archive Language".
Version 1.3b, which is widely available, contains a bug later corrected in version 1.4: after a save instruction, the Z-machine requires that a success code is saved in a particular place (which differs depending on the version). Versions of the Quetzal standard before 1.4 have reference only to the instruction after the save, which complicates finding the correct place to put the success code.