MS-DOS Versions

MS-DOS has been around for a very long time. It started off as QDOS (Quick
and Dirty Operating System) which was developed by Seattle Computer Products
to run on IBM’s new PC. This list covers most versions up to Windows 9x although a number of the more obscure versions of DOS have been omitted. See Wikipedia for a more comprehensive and up to date list.

Version Date Comments
1.0 1981 The original version of MS-DOS. This was a renamed version of QDOS
which had been purchased by an upstart company called Microsoft.
1.25 1982 This added support for double-sided disks. Previously the disk had
to be turned over to use the other side
2.0 1983 This added support for IBM’s 10 MB hard disk, directories and double-density
5.25″ floppy disks with capacities of 360 KB
2.11 1983 Support for foreign and extended characters was added.
3.0 1984 Support for high-density (1.2 MB) floppy disks and 32 MB hard disks
was added.
3.1 1984 Network support was added.
3.3 1987 This release was written to take advantage of IBM’s PS/2 computer range.
It added support for high density 3.5″ floppy disks, more than one partition
on hard disks (allowing use of disks bigger than 32 MB) and code pages.
4.0 1988 This version provided XMS support, support for partitions on hard disks
up to 2 GB and a graphical shell. It also contained a large number of bugs
and many programs refused to run on it.
4.01 1989 The bugs in version 4.0 were fixed.
5.0 1991 This 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.
5.0a 1992/3 This was a minor bug fix which dealt with possibly catastrophic problems
with UNDELETE and CHKDSK.
6.0 1993 This was a catch-up with Novell’s DR-DOS 6. It added a disk-compression
utility called DoubleSpace, a basic anti-virus
program and a disk defragmenter. It also finally
included a MOVE command, an improved backup program,
MSBACKUP and multiple boot configurations. Memory management was also improved
by the addition of MEMMAKER. A number of older
utilities, such as JOIN and RECOVER were removed.
The DOS Shell was released separately as Microsoft felt that there were
too many disks.
6.2 1993 Extra security was built into DoubleSpace following complaints of data
loss. A new disk checker, SCANDISK, was also
introduced, as well as improvements to DISKCOPY
and SmartDrive.
6.21 1993 Following legal action by Stac Electronics, Microsoft released this
version which had DoubleSpace removed. It came with a voucher for an alternative
disk compression program.
6.22 1994 Microsoft licenced a disk-compression package called DoubleDisk from
VertiSoft Systems and renamed it DriveSpace,
which was included in this version.
7.0 1995 This version is part of the original version of Windows 95. It provides
support for long filenames when Windows is running, but removes a large
number of utilities, some of which are on the Windows 95 CD in the \other\oldmsdos
directory.
7.1 1997 This version is part of OEM Service Release 2 and later of Windows
95. The main change is support for FAT 32 hard disks, a more efficient
and robust way of storing data on large drives.

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