From IFWiki

Ozmoo sample img.png
Links Home page Download
Developers Fredrik Ramsberg, Johan Berntsson
Format Z-code
Interaction style
Systems BBC Micro/Acorn Electron, Commodore 64/128, Other
System details Use a Windows, Mac or Linux computer to run the make script (make.rb) which builds disk image(s) for the system you want to play on (Commodore 64, 128, Plus/4, MEGA65 or Commander X16 + there's a port for Acorn/BBC). You can also use Ozmoo Online instead of installing it on your computer.
Latest version 14.24 / 17 May 2024
Status Stable
Uses interpreter
Multimedia support color effects (all platforms), loader image (C64 and Plus/4), sound effects (MEGA65)
License GPL 2.0
Browse the software database
Edit this infobox

Ozmoo is an interpreter for the Z-machine on the Commodore 64, Commodore 128, Commodore Plus/4, MEGA65, Commander X16 and Acorn/BBC, written in assembler by Johan Berntsson and Fredrik Ramsberg. The Ozmoo software package is used to bundle games with the interpreter and produce disk images for the target platform. It can be downloaded and used on a Windows, Linux or Mac OS X computer, or used in a web browser at Ozmoo Online. Ozmoo was nominated for an XYZZY Award for Best Technological Development of 2018.

It supports Z-machine versions 1, 2, 3, 4, 5, 7 and 8.

License: GPL 2.0 - Can be used freely, even in commercial projects.


  • Named saves (Use a blank, formatted disk for saves, in the same drive as the game, or in a different drive.)
  • Customizable colours for a primary colour scheme and a darkmode colour scheme, which the player can toggle between.
  • Ozmoo fits more text on the screen than Infocom's terps. It uses all 40 columns, adds linebreaks smarter and has a smarter MORE prompt.
  • Embedding a custom font (character set). A few fonts are included with the distribution, but you can also supply your own font or, of course, use the system font.
  • Can cache the story file to REU (Ram Expansion Unit) for faster gameplay. REU owners can also play a game for a dual disk drive system with just one drive.
  • Supports Undo (requires C64 with REU, C128 or MEGA65)
  • Offers an optional scrollback buffer feature, to let users re-read text that has scrolled off screen.
  • Supports timed input, as used in Borderzone.
  • The interpreter and as much of the story file as possible is stored in compressed form in a single file, which means loading is quick if the player has any kind of fastload cart.
  • The person bundling the game with Ozmoo can optimize which parts of the story are loaded with the initial file, to minimize disk reads at the beginning of the game.
  • A loader image can be added on C64 and Plus/4.
  • A small game built for C64 or Plus/4 (story file < about 50 KB) can be stored as a single file which does not require a disk drive to play. Save/restore does require a disk drive.
  • A game up to about 190 KB can be stored on one or two disk sides, and played on a system with a single 1541 drive.
  • Larger games (< about 350KB) can be built and stored on two or three disk sides, but they will require a system with dual 1541 drives, or a single 1541 drive and an REU, to play.
  • Any size game can be stored on a 1581 disk image (.d81) and played using an SD2IEC or an actual 1581 drive. For games on 1581 disks, it is safe to use the game disk as a save disk as well, eliminating the need to swap disks when saving/restoring.
  • Custom alphabet table (typically used for non-English games)
  • Custom character mappings (Needed to play non-English games because accented characters don't exist in PETSCII)
  • Comes with the fonts and character mappings needed for games in Swedish, Danish, German, Italian, Spanish and French.
  • Automatic patching of Beyond Zork to work on 40 column screens.
  • Supports automatically changing "x" to "examine" in player input. Useful in Infocom games which don't support "x" as a synonym for "examine".


By format ADRIFTAdvSysAGTAlanGlulxHugoMagnetic ScrollsTADSZ-code
By system BrowserAndroidiOSLinuxmacOSWindows
Browse Recommended interpretersSearch formDrilldown
Other software Authoring systemsUtilities