This page was last modified 14:36, 26 May 2023 by Mars2000you. Based on work by SjaaQ and Gdx.



MSX-DOS 2 is an major update of MSX-DOS. It was developed solely by ASCII since Microsoft left the standard after the release of the MSX2. It consists of

  • a cartridge with a new DISK-BASIC 2.0
  • MSX-DOS 2 disks that contain new system files (MSXDOS2.SYS and COMMAND2.COM, this last file containing the internal DOS commands) and various tools

Although Disk-BASIC can run on MSXs with at least 16KB RAM and MSX-DOS 1 requires only a minimum of 64kB RAM, MSX-DOS 2 needs a minimum of 128kB with Memory Mapper even under Basic.

It was a problem particularly in Japan as the vast majority of MSX2 systems (and all MSX2+ systems) only had 64kB of RAM. As such ASCII offered versions both with and without additional RAM - see Japanese MSX-DOS 2.

This was not as much of an issue in Europe as almost all MSX2 computers there had at least 128kB standard.

New features

MSX-DOS 2 starts with the version 2.20. The main new features are:

  • Management of folders (sub-directories)
  • Environment variables
  • Memory Mapper
  • Temporary pipe files
  • Redirection of peripherals.

Redirection can be disabled with the SET REDIR=OFF command. Therefore, COMMAND2.COM will work in a very similar way to MSX-DOS 1. In addition, MSX-DOS 2 handles errors better.


In July 1988, ASCII published Japanese MSX-DOS 2 in Japan.

European versions were released, starting in mid 1989 in the Netherlands. All are based on the version 2.20 from ASCII. Much controversy surrounded the European versions over licensing rights, in particular between Sparrowsoft and HSH.

Known European MSX-DOS 2 releases (licensed or not):

  • Sparrowsoft MSX-DOS 2.10 (buggy early release with DISK-BASIC 0.0)
  • Sparrowsoft MSX-DOS 2.20
  • HSH MSX-DOS 2.20
  • MK Public Domain MSX-DOS 2.20
  • MSX Club West-Friesland MSX-DOS 2.22

The MSX turbo R computers (Panasonic FS-A1ST and FS-A1GT) have an updated version of the OS, it's kernel 2.30 or 2.31 with MSXDOS2.SYS 2.30 and COMMAND2.COM 2.30 or 2.31. These machines need a memory mapper of at least 256kB. The ROM part is built-in while the internal commands are still available in the COMMAND2.COM provided on disk.

Later, coders of the MSX scene released patches to upgrade

  • COMMAND2.COM versions 2.20 and 2.31 to 2.4x (mainly C.P.U. and The New Image) - see the MSX-DOS Internal Commands page
  • MSXDOS2.SYS version 2.30 to 2.32 (Hardware Partners), 2.33 (Desire In Envy) or 2.40 (NYYRIKKI) - see Links section

Many more modern mass storage device options for MSX use the Nextor kernel which is derived from MSX-DOS 2.