MS-DOS 5.0

MS-DOS 5.0 was a major upgrade. It allowed parts of DOS to load itself in the high memory area and certain device drivers and TSRs to run in the unused parts of the upper memory area between 640K and 1024K. This version also added support for IBM's new 2.88 MB floppy disks. An improved BASIC interpreter and text editor were included, as was a disk cache, an undelete utility and a hard-disk partition-table backup program. After the problems with MS-DOS 4, it also provided a utility to make programs think they were running on a different version of MS- DOS.
Couple of minor bugs with Undelete and Chkdsk utilities were fixed in version 5.0a.

As the competition in the OS market heated up, Digital Research released in September 1991
DR- OS 6.0, which was far more advanced then current version of Microsoft's MS-DOS 5.0. Microsoft was forced to catch-up and in March 1993 released another major version MS-DOS 6.0.