Ozmoo Online

Ozmoo Online

[Switch to Ozmoo Online for Acorn]

Latest news

2024-07-05: Updated to Ozmoo 14.36, adding support for Undo on X16, better calculation of # of save slots, plus bugfixes and minor optimizations.

2024-06-28: Added the PunyInform game Who Kidnapped Mother Goose by Garry Francis to the Story File dropdown menu.

2024-06-24: Created a build of Trinity for C64 (requires REU or dual 1541 drives or a 1581 drive, REU recommended!), download c64_trinity.zip

2024-06-24: Updated to Ozmoo 14.30, allowing for slightly larger dynmem on C64.

2024-06-17: Updated to Ozmoo 14.29, fixing several bugs. See releases for details.

Recent noteworthy updates

  • Added a page for Ozmoo for Acorn.
  • Added link to Lurking Horror and Sherlock with sound for MEGA65
  • Ozmoo now supports the Commander X16 as a target

Ozmoo is a Z-code interpreter for the Commodore 64, 128, Plus/4, the MEGA65 and the Commander X16. 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 1, 2, 3, 4, 5, 7 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 sound effects (sound is only supported for MEGA65, and not at all when building a game in Ozmoo Online).

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 to 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, unless you're playing on a MEGA65, in which case Dialog and relatively lightweight Inform 7 titles may be enjoyable (Check the XL Stack option when building an Inform 7 game though, or it will likely crash at some point). 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.

Build game

Common settings
Story file:   
Language / Font:  
(*) Please learn more about Ozmoo and fonts first!
Command history:
Colour scheme
Check out different colour combinations here.
For colours to work well on real hardware, use black or white background or foreground!
Statusline:     (z1-z3 only!)
Input text:     (z1-z4 only!)
Splashscreen text:

Platform specific settings
 Commodore 64Commodore 128Plus/4MEGA65Commander X16
Loader image:    (*.kla)      (*.mbo)    
Build mode:          
Scrollback buffer:          
Smooth scrolling: (40 col only)      
Inform 7 XL stack:        

Upload Z-code file (.dat .z1 .z2 .z3 .z4 .z5 .z7 .z8), Blorb file (.blorb .blb .zblorb .zlb), Koala Paint multicolour image (.kla) or Multi-Botticelli image (.mbo)

Your files: