Z-machine versions

There are at least 10 different versions of the Z machine out there:

• Versions 1 through 6 were created by Infocom in the 1980s. These were de facto defined by the behavior of their proprietary interpreters.
• These were reverse-engineered in the late 1980s and early 1990s, resulting in the first open-source interpreters.
• Graham Nelson made some minor extensions in 1995 to allow for larger story files, creating versions 7 and 8 of the spec. (The immediate impetus for the expansion was to support Jigsaw.) Most, if not all, modern Z machine interpreters support z7 and z8 story files.
• In the late 1990s, online discussion led to the publication of a "modernized" Z-machine specification (covering versions 1 through 8). This was labelled Z-Machine Standards Document 1.0. The Z-machine has subsequently been accepted as being defined by this document, rather than by Infocom's legacy implementations.
• In the early 2000s, there was a great deal of discussion about new version 9 and 10 extensions, but these were never resolved.
• In 2013, Zzo38 created (another) version 9 and 10 of the spec, with a number of extensions allowing even larger story files, finally giving Z-machines XOR support, and many other changes. These versions are not described in the 1997 Z-machine specification 1.0, nor in the 2006 Z-machine specification v1.1 (the most recent version), nor in the draft Z-machine specification v1.2; the only known Z machine interpreters that support these versions are Zzo38's own Aimfiz and Fweep.

Links

• This compares versions 1-8
• Zzo38 spec for version 9 and 10 of Z-machine files (dead link)