Happy Birthday, MS-DOS -- 30 candles 27 July 1981- 27 July 2011

Happy Birthday, MS-DOS -- 30 candles ( 27 July 1981- 27 July 2011)
MS-DOS ( short for Microsoft Disk Operating System) is anoperating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating systems offering a graphical user interface (GUI), in particular by various generations of the Microsoft Windows operating system.

The following versions of MS-DOS were released to the public.

• MS-DOS 1.x
  • Version 1.12 (OEM) - Compaq release of PC-DOS 1.10
  • Version 1.19 (OEM)^[7] - Zenith OEM
  • Version 1.25 (OEM) - Microsoft repackaging of PC-DOS 1.10
• MS-DOS 2.x - Support for 10 MB hard disk drives and tree-structure filing system
  • Version 2.0 (OEM)
  • Version 2.1 (OEM)
  • Version 2.11 (OEM)
  • Version 2.2 (OEM)
  • Version 2.21 (OEM)
• MS-DOS 3.x
  • Version 3.0 (OEM) - Support for larger hard disk drives
  • Version 3.1 (OEM) - Support for Microsoft Networks
  • Version 3.2 (OEM)
  • Version 3.21 (OEM)
  • Version 3.25 (OEM)
  • Version 3.3 (OEM)
  • Version 3.3a (OEM)
  • Version 3.3r (OEM)
  • Version 3.31 (OEM) - Compaq 3.31 supports FAT16 and larger drives.
  • Version 3.35 (OEM)
• MS-DOS 4.x - includes a graphical/mouse interface.
  • Version 4.00 (OEM)
  • Version 4.01 (OEM) - IBM patched Version 4.00 before Microsoft released it.
  • Version 4.01a (OEM)
• MS-DOS 5.x
  • Version 5.0 (Retail) - includes a full-screen editor. A number of bugs required reissue.
  • Version 5.0a (Retail) - With this release, IBM and Microsoft versions diverge.
  • Version 5.0.500 (WinNT) - All Windows NT 32-bit versions ship with files from DOS 5.0
• MS-DOS 6.x
  • Version 6.0 (Retail) - Online help through QBASIC. Disk compression and antivirus included.
  • Version 6.2 (Retail) - Microsoft and IBM alternate versions, IBM has 6.1, 6.3
  • Version 6.21 (Retail) - Stacker-infringing DBLSPACE removed.
  • Version 6.22 (Retail) - New DRVSPACE compression.
• MS-DOS 7.x
  • Version 7.0 (Win95,95A) - Support for long file names. New editor.
  • Version 7.1 (Win95B-Win98SE) - Support for FAT32 file system
• MS-DOS 8.0
  • Version 8.0 (WinME) - Integrated drivers for faster Windows loading.
  • Version 8.0 (WinXP) - DOS boot disks created by XP and later contain files from WinME. The internal DOS is still 5.0

Microsoft DOS was released through the OEM channel, until DRI released DR-DOS 5.0 as a retail upgrade. With PC-DOS 5.00.1, the IBM-Microsoft agreement started to end, and IBM entered the retail DOS market with IBMDOS 5.00.1, 5.02, 6.00 and PC-DOS 6.10, 6.30, 7.00 and 2000.

A number of beta versions have surfaced on the Internet, such as 5.0 (a ten-diskette version in the same vein as 4.0), 7.00 beta 1 (based on 6.00), 7.00 beta 2 (based on 6.22). An OEM source package for 6.00, and a late release of 6.2(b) have also been seen. These are not retail versions.