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Microsoft's original disk operating system, MS-DOS, was the first popular operating system for the IBM PC. It employs a command line interface and a batch scripting facility via its command interpreter, command.com.

The progenitor of MS-DOS was created by a company called Seattle Computer Systems. The original name was QDOS, for Quick and Dirty Operating System. It was designed as a short-term clone of the market-leading CP/M operating system to provide compatibility with the existing installed base of business applications such as WordStar and dBase. Microsoft bought the product for re-sale to IBM and it was renamed PC-DOS (the IBM-badged version) and MS-DOS (the version badged by Microsoft themselves). The two products were identical to begin with but would eventually diverge. (See PC-DOS.)

In Microsoft's development from a specialist programming language supplier in the 1970s to its eventual status as the dominant firm in the computer industry, DOS was the key product. It was revenue from MS-DOS sales (particularly from exclusive OEM per-unit contracts -- which were not finally ruled illegal in the USA until considerably later), that made the explosive growth of the company possible, and MS-DOS continued to be the largest single contributor to Microsoft's earnings well after the company had become more famous for Windows. Incidentally, it was not until well after the release of Windows 95 that aggregate Windows revenue surpassed aggregate DOS revenue.

MS-DOS grew to include more features from other operating systems. MS-DOS 2.0 introduced features from UNIX such as subdirectories, command input/output redirection, and pipess.

MS-DOS was not designed to be a multi-user or multitasking operating system, but many attempts were made to retrofit these capabilities. Many programs were developed using the Terminate and Stay Resident (TSR) technique and other mostly-undocumented functions to provide pop-up applications including Borland's popular Sidekick product. Add-on environments like DESQView attempted to provide multitasking, and achieved some success when later combined with the memory-management hardware of the Intel 80386 processor.

After the release of the Apple Macintosh in 1984, people became interested in a graphical user interface. Many programs created their own graphical interface, such as Microsoft Word for DOS, XTree, and the Norton Shell. However, that required duplication of effort and did not provide much consistency, so complete GUI environments were created.

IBM and Microsoft began work on a joint project called OS/2, originally a protected-mode version of MS-DOS with a GUI, but Microsoft soon abandoned the project to devote full resources to Windows NT. Digital Research created the GEM environment which reached minimal popularity, but both were soon eclipsed by Microsoft's Windows GUI package, reportedly due to Microsoft's exclusive agreements with computer hardware vendors.

Early versions of Microsoft Windows were a program which ran under MS-DOS and its clones. Later versions were launched under DOS but "extended" it by going into protected mode. Still later versions of MS Windows ran independently of DOS but included much of the old code such that it could run in virtual machines under the new OS and the latest versions of MS Windows are continually dropping ever more of the old DOS.

Under Linux it is possible to run copies of DOS and many of its clones under dosemu, a Linux-native virtual machine for running real mode programs. There are a number of other emulators for running DOS under various versions of UNIX, even on non-x86 platforms.

Table of contents
1 Main commands
2 Sample output
3 Clones
4 See also
5 External links

Main commands

DIR      List directory content
TYPE     Type file content to screen
COPY     Copy a file
REN      Rename a file
DEL      Delete a file
MD       Make a new directory
CD       Change current directory
RD       Remove a directory

Sample output

Volume in drive C has no label
Volume Serial Number is 1234-5678
Directory of C:\\

AUTOEXEC TTZ 1,120 07-26-03 1:03a MSDOSS~1 BAK 1,779 01-21-96 7:12p SETUP 01-21-96 9:06p HIDDEN TX1 19,296 01-21-96 7:27p CONFIG BAK 122 01-21-96 2:25p GAMES 01-21-96 9:06p WS_FTP LOG 128 01-21-96 12:36p CONFIG DOS 50 01-21-96 2:25p AUTOEX~2 BAK 1,150 01-22-03 2:13p CYGNUS 01-21-96 9:38a JAVA 01-21-96 9:40a TMP 01-21-96 4:01p E 01-21-96 4:23p COMMAND COM 93,890 01-21-96 10:22p WINDOWS 01-21-96 8:42p MOUSE 01-21-96 8:45p BASIC 01-21-96 5:09p MASM 01-21-96 5:09p CONFIG SYS 122 01-31-03 11:50p PROGRA~1 01-21-96 6:26p MYDOCU~1 01-21-96 9:00p AUTOEXEC BAT 1,150 07-26-03 1:03a
       10 file(s)     12,056,573 bytes
       12 dir(s)        1,214.84 MB free


Several similar products were produced by other companies. In the case of PC-DOS and DR-DOS, it is common but incorrect to call these "clones". PC-DOS and MS-DOS were (to continue the genetic analogy) "identical twins" that diverged only in adulthood and eventually became quite different products; DR-DOS was a clone of itself once removed: see DR-DOS for details.

See also

External links