IBM PC-DOS

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**PC-DOS**

A typical command line in PC DOS.
Company/ developer:	IBM
OS family:	DOS
Source model:	Closed source
Latest stable release:	7.0 revision 1 (a.k.a. PC DOS 2000) / May, 1998
Default user interface:	CLI
License:	Proprietary
Working state:	Historic

IBM PC-DOS was one of three major operating systems that dominated the personal computer market from about 1981 to 1995. The original 1981 arrangement between IBM and Microsoft was that Microsoft would provide the base product and that both firms would work on developing different parts of it into a more powerful and robust system, and then share the resultant code. MS-DOS and PC-DOS were to be marketed separately: IBM selling to itself for the IBM PC, and Microsoft selling to the open market. ThinkPad products currently have a copy of the latest version of PC-DOS in their Rescue and Recovery partition.

The final release, PC DOS 2000, found its niche in the embedded software market and elsewhere. It was released to correct issues with the Year 2000 problem. Versions 7 and 2000 supported a diskette format known as XDF, which allowed for more data to be written to a standard floppy disk than usual.

1 Versions
2 References
3 See also
4 External links

[edit] Versions

PC DOS 1.0 - August 1981 – initial release with the first IBM-PC (COMMAND.COM is 3231 bytes. FAT-12, with no subdirectory support.
PC DOS 1.1 - May 1982 – support for 320 kB double-sided floppy disk. COMMAND.COM has 4959 bytes.
PC-DOS 2.0 - March 1983 - had a maximum disk partition size of 10MB, came on two 180 kB 5.25-inch disks or one double-sided 360 kB disk. COMMAND.COM has 17664 bytes.
PC DOS 2.1 - October 1983 – support for IBM PCjr. COMMAND.COM has 17792 bytes.
PC DOS 3.0 - August 1984 - support added for DS/HD 1.2MB floppy disk drives. Introduces FAT-16 file system on hard drives. COMMAND.COM has 22042 bytes.
PC DOS 3.1 - March 1985 - COMMAND.COM has 23210 bytes.
PC-DOS 3.2 - December 1985 - required 128 kB RAM and came on one 720 kB disk or two 5.25 disks. COMMAND.COM has 23791 bytes.
PC DOS 3.3 - April 1987 – support for IBM PS/2: 1.44 MB floppy disk drives, added codepage support (international character sets). COMMAND.COM is 25307 bytes.
PC DOS 4.0 - June 1988 – added DOS Shell & support for hard disks of >32MB using the format from Compaq DOS 3.31. But it had many bugs and less free conventional memory than before. Generally regarded as an unpopular release. COMMAND.COM has 37637 bytes.
PC-DOS 4.01 - August 1988 - came on two 3.5-inch DD diskettes (720K) and required 256 kB RAM. Mostly bug fixes. Maximum disk partition size was 2000MB.
PC-DOS 5.0 - May 1991 - three 3.5-inch DD diskettes. Able to run DOS in HMA. COMMAND.COM has 47987 bytes.
PC-DOS 5.00.1 - February 1992 - bug fixes. COMMAND.COM has 48025 bytes.
PC-DOS 5.02 - September 1992 - adds support for portable computers and ISO fonts COMMAND.COM has 47990 bytes.
PC-DOS 6.0 - May 1993 - Beta version, not released.
PC-DOS 6.1 - June 1993 - four 3.5 inch 1.44M disks. PC-DOS and MS-DOS now offer significantly different utilities. IBM dropped QBasic and its associated MS-DOS text editor. Replaced editor with E; but added no programming language. COMMAND.COM has 52589 bytes.
PC-DOS 6.2 - not released
PC-DOS 6.3 - December 1993 - five 3.5 inch 1.44M disks. Enhanced several utility programs. Became popular with OEMs because MS-DOS had stopped stand-alone, non-Windows releases at their version 6.22. COMMAND.COM has 54654 bytes.
PC-DOS 7 - November 1994 - could purchase in floppy or CD-ROM format. The diskette set had a normal 1.44M installation floppy and four in a special 1.88M XDF format. Added the REXX interpretive language. Included enhanced utilities. COMMAND.COM has 52956 bytes.
PC DOS 2000 - April 1998 - six diskettes (installation and five XDF) or one CD-ROM. A Year 2000 Certified release of v7.0 with fixes for Year 2000 problem (Y2K). Floppies were labeled "PC DOS 2000, Includes PC DOS 7". COMMAND.COM has 52965 bytes.