2020-11-30: Installed Ozmoo 4.34. [Show what has changed].
2020-09-28: Installed Ozmoo 4.21. [Show what has changed].
2020-09-28: Installed Ozmoo 4.3, which can be used to build Beyond Zork. [Show what has changed]. Added Beyond Zork to the public story files.
2020-09-21: Installed Release 4 of Ozmoo. [View release note]. Added options to specify cursor blink, shape and colour, and option to add loading image.
Ozmoo is a Z-code interpreter for the Commodore 64. It was written by Johan Berntsson and Fredrik Ramsberg, and released in 2018 under the GPL 2.0 license, meaning it can be included with games which are given away or sold. Ozmoo supports Z-code versions 3, 4, 5 and 8. You can use this page to build the interpreter and bundle it with a game. There is more information on the project homepage on GitHub.
Ozmoo was designed to be bundled with a game, much in the same way as the original Infocom interpreters. To do this, you run a Ruby script called make.rb which is included in the Ozmoo distribution. It assembles the interpreter, taking into account the Z-code version and the options specified when calling make.rb, adds as much as possible of the Z-code file, compresses the result and stores it as a file on a disk image. It then stores all the parts of the story that the game may need to load during gameplay in raw sectors on the disk.
Ozmoo can be downloaded and used to build games on Windows, Linux and Mac OS X. As an alternative, we have set up this page where you can build games online. It doesn't support all the possibilities which Ozmoo offers, but enough to get started. Options which are currently not supported on this page include user-supplied custom fonts, custom key-mappings, virtual memory preloading optimization and custom stack size.
Z-code files typically have names ending with .dat, .z3, .z4, .z5 or .z8. They can mainly be found in Infocom games (yes, you can grab a .dat file from say Zork 1 for MS-DOS and use it build a version for C64 with Ozmoo!) and on if-archive. Z-code files produced by Infocom are usually quite fast on Ozmoo. Z-code files produced by Inform 5 or Inform 6 may at least be fast enough to be fun, but it depends on how much processing they do. Z-code files produced by Inform 7 or Dialog are pretty much guaranteed to be horribly slow. There is also ZILF, a modern compiler for ZIL, the language Infocom used to write their games. Z-code files produced by ZILF should typically play just fine on Ozmoo.