MS-DOS 1.25

MS-DOS 1.25
	Version of MS-DOS
Version	1.25
Release date	1982-08
Replaces
	MS-DOS 1.24
Replaced by
	MS-DOS 1.26

MS-DOS 1.25 was released in August 1982 as the first general release to OEM customers other than IBM, so it was used by all the first clone manufacturers. Some OEMs labeled their release with different version numbers (e.g. COMPAQ), but they are all based on version 1.25.^[1]

It supported both single sided (160KB) and double sided (320KB) 5.25" floppies and there was no sub-directory support (all files must be located in the root directory). As a result of that, \, / and other symbols can be used in file names.

Versioning[edit | edit source]

MSDOS.SYS in this release should always report version 1.25 and COMMAND.COM will report version 1.17, 1.18 or custom versions depending on the revision. The original non-OEM MS-DOS 1.25's COMMAND.COM reports version 1.17 according to the source code released by Microsoft.

Some OEM releases has an extra H or D at the end of the version string. H means the source was assembled with the HIGHMEM switch and D means the DSKTEST switch was used.

Changes from MS-DOS 1.24[edit | edit source]

MS-DOS 1.24 corresponds to IBM PC-DOS 1.10^[1] and there is only one minor change between the two versions as described by the writer of DOS, Tim Paterson.^[1] The change was a marker (00) being placed at end of the directory to speed up searches.