This page was last modified 12:42, 20 March 2022 by Mars2000you. Based on work by Gdx and Briqunullus and others.



Despite the 1984 copyright of MSX-DOS 1, this OS, also known as MSX-DOS, did not actually become available until spring 1985, and then only to OEMs. The first device to ship with MSX-DOS 1 was the National CF-3300, which was released in early summer 1985. However, some earlier versions of MSX-DOS have been distributed with software that has been released at a later date.

MSX-DOS 1 can run on any MSX computer with disk drive and at least 64kB of memory. It does not support memory mappers and also lacks support for sub-directories. It includes only two files: MSXDOS.SYS and COMMAND.COM (that contains 14 internal commands), and no any tool is provided on the official MSX-DOS 1 disks.

The most common version of MSXDOS.SYS and COMMAND.COM that was typically distributed with external disk drives or with computers with an integrated drive was MSX-DOS 1.03 and COMMAND 1.11. There exist two versions of COMMAND 1.11 and one contains a bug when concatenating files. This version was distributed by Philips and maybe others.

For more information read The History of MSX-DOS.

Known official releases

0.26 0.12 BDS-C released in 1986 for MSX but the first CP/M version was released in 1979
1.00 1.00
1.00 1.01 WieWat Financial Suite
1.00 1.02
1.00 1.07 National CF-3300
1.01 1.07 Spectravideo SVI-707
1.01 1.08
1.02 1.10 Canon VF-100
1.03 1.11 Kawai KMC-5000
National FS-4600F, FS-4700, FS-5000, FS-5500F1, FS-5500F2
Panasonic FS-A1F, FS-A1FM, FS-A1FX, FS-A1WX, FS-A1WSX
Panasonic FS-IFA1, FS-PW1, FS-SR021
Philips NMS 1210, NMS 1211, NMS 1212, NMS 8245, NMS 8250, NMS 8255, NMS 8280
Philips VG-8230, VG-8235
Phonola VG-8235, NMS 8245, NMS 8280
Sony HB-F700, HB-F900, HB-G900
Spectravideo SVI-738
unknown version unknown version National FS-CF351
Panasonic FS-FD1, FS-FD1A
Sanyo PHC-70FD, PHC-70FD2, PHC-77
Sony HB-F500F, HB-F500P, HB-T600, HBD-20W, HBD-F1
Toshiba HX-34
Yamaha YIS-805

Note about the Japanese Sony HB-F500: There is no separate MSX-DOS 1 disk coming with this computer. We don't know whether the application disk includes it, as the exact contents of this disk is presently unknown.


MSX-DOS consists of two files with very specific tasks. MSXDOS.SYS acts as a BDOS function dispatcher and as an error handler. COMMAND.COM provides the system with the prompt and the internal commands for disk management. Due to this modular concept, MSXDOS.SYS and COMMAND.COM versions can be used in any combination. However, some combinations can cause system crashes with batch files. These crash possibilities are:

  1. When the command line is longer than 70 bytes.
  2. When the line in the batch file is longer than 128 bytes.
  3. When the number of batch parameters is more than 64.
v1.00 or 1.01 v1.02 or later
COMMAND.COM v1.00 to 1.09 maybe (1, 2, 3) maybe (2, 3)
v1.10 always maybe (3)
v1.11 maybe (1) never

The COMMAND 1.11 bug

After release of COMMAND 1.11 a bug was discovered when concatenating files. The bug was quickly fixed, but the version number wasn't altered. Apparently this led to confusion with OEMs. At least Philips got it wrong and released the bugged version. Within COMMAND.COM there is a hidden attribution string. One reads 'COMMAND version 1.11 for MSX-DOS amended by Hal-F 07/30/85', the other 'MSX-DOS version 2.2 by Tim Paterson 03/06/84'. The correct version of COMMAND 1.11 is the one with Tim Paterson's name in it as can be seen in the screenshots below.

To verify COMMAND version use CMDVER verification utility under MSX-DOS. Or use SHA1 checksums below.

Version SHA1 checksum
COMMAND.COM 1.11 Hal-F 22f57addaa1ff707318a214a03541588574cd855
COMMAND.COM 1.11 Tim Paterson af5f2ef3eac4062638f5d8069515e6bcee788e7d

COMMAND 1.11 Hal-F version
COMMAND 1.11 Tim Paterson version

Unofficial releases

Many unofficial versions of MSX-DOS 1 have been developed over the years. See MSX-DOS 1 Clones for more info.