From Wikipedia, the free encyclopedia
Developer(s)openMSX Team
Stable release
18.0 / June 12, 2022; 9 months ago (2022-06-12)[1]
Written inC++ (core), Tcl, (openmsx-catapult: wxWidgets)[2]
Operating systemPOSIX and Windows
LicenseGNU GPLv2+

openMSX running CBIOS

openMSX is a free software emulator for the MSX architecture. It is available for multiple platforms, including Microsoft Windows and POSIX systems such as Linux

For copyright reasons, the emulator cannot be distributed with original MSX-BIOS ROM images. Instead, openMSX includes C-BIOS, a minimal implementation of the MSX BIOS, allowing some games to be played without the original ROM image. It is possible for the user to replace C-BIOS by native BIOS if they prefer.

OpenMSX emulates a large amount of MSX systems and MSX related hardware, including:

Also some computer systems similar to MSX are emulated, like the SpectraVideo SVI-318/328, ColecoVision and Sega SG-1000.

Notable features include:

  • Hard- and software Scalers
  • Debugging
  • Tcl Script Support
  • Cheat Finder (through Tcl)
  • Game Trainers (through Tcl)
  • Audio/Video recording
  • Reverse support (go back in emulated time to correct mistakes or debug what happened)

OpenMSX has an open communication protocol to communicate with the openMSX emulator. Utilizing this communication protocol enables to write versatile add-ons for openMSX. Projects making use of this protocol include the following applications:

  • openMSX Catapult (by the openMSX team)
  • openMSX Debugger (by the openMSX team)
  • openMSXControl plugin
  • NekoLauncher openMSX
  • openMSX Peashooter
  • openMSX Control Plugin for Gedit

Currently Catapult, a GUI developed for the emulator that is part of the project, is being redeveloped utilizing Python and the Qt toolkit.

The openMSX Debugger is also under development, written in C++, also utilizing the Qt Toolkit.


  1. ^ "Home". Retrieved 12 June 2022.
  2. ^ "Debian -- Details of package openmsx-catapult in jessie". Retrieved 2017-03-10.