MS-DOS
MS-DOS or MSDOS - MicroSoft Disk Operating System
Microsoft founder Bill Gates acquired a Personal Computer Disk Operating System by indirect means from developer Gary Kildall. Kildall is the creator of Control Program for Microcomputers (CP/M), the operating system used on many of the early personal computers. Microsoft's QDOS, and subsequently MS-DOS is speculated to have been directly copied from CP/M.
MS-DOS is the most well known and widely used disk operating system for the personal computer. MS-DOS has been though a number of versions and under different release names. In 2000 Microsoft claims to have ceased all development of MS-DOS in favor of its elimination from their graphical user interface product Microsoft Windows. Yet the claim may be false, as the Windows Kernel, even to this day, still contains legacy original MS-DOS code. That code has been patched to being serviceable on new processor types.
MS-DOS versions 6.0 and 6.22 remain available for download via their MSDN, volume license, and OEM license partner websites, for customers with valid login credentials. Version 6.22 was the last official release of MS-DOS by Microsoft in 1994. In 1995 Microsoft escalated an anti-competitive practice forcing computer manufacturers to lock in licenses to prevent competing operating systems from being used. In 1991, the U.S. government Federal Trade Commission began investigating Microsoft's licensing procedures, resulting in a 1994 settlement agreement limiting Microsoft to per-copy licensing.
MS-DOS commands since version 5.0 were divided into internal and external types. The internal commands reside in COMMAND.COM, which loads into memory when the computer system is started; these commands do not reside on disk. The external commands are files that do reside on disk and have an extension of .COM, .EXE, or .BAT. Both command types are executed from the MS-DOS prompt.
internal commands
BREAK CALL CHCP CHDIR(CD) CLS COPY CTTY DATE DEL(ERASE) DIR ECHO EXIT FOR GOTO IF MKDIR(MD) PATH PAUSE PROMPT REM RENAME(REN) RMDIR(RD) SET SHIFT TIME TYPE VER VERIFY VOL
external commands
APPEND.EXE ASSIGN.COM ATTRIB.EXE BACKUP.EXE CHKDSK.EXE COMMAND.COM COMP.EXE DEBUG.EXE DISKCOMP.COM DISKCOPY.COM DOSKEY.COM DOSSHELL.COM EDIT.COM EDLIN.EXE EMM386.EXE EXE2BIN.EXE EXPAND.EXE FASTOPEN.EXE FC.EXE FDISK.EXE FORMAT.COM GRAFTABLE.COM GRAPHICS.COM HELP.EXE JOIN.EXE KEYB.COM LABEL.EXE MEM.EXE MIRROR.COM MODE.COM MORE.COM NLSFUNC.EXE PRINT.EXE QBASIC.EXE RECOVER.EXE REPLACE.EXE RESTORE.EXE SETVER.EXE SHARE.EXE SORT.EXE SUBST.EXE SYS.COM TREE.COM UNDELETE.EXE UNFORMAT.COM XCOPY.EXE
