MS-DOS is an acronym for Microsoft Disk Operating System.

Version 6.00 was first version of MS-DOS 6 and was released in March of 1993 and added more utilities and features; a disk defragmenter, disk compression, an anti-virus, a new backup system and computer to computer file transfer tools. The successor to this was 6.20 which was released in November of 1993 and fixed a few bugs from version 6.20 and added the ScanDisk program. The next version of MS-DOS 6 was 6.21 which was released in March 1994 and removed the DoubleSpace utility due to legal reasons. The final version was 6.22 which was released in June 1994 and added “Enhanced Tools”, such as a DriveSpace and an additional supplemental disk was included.