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 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. Version 6.22 was the last official release of MS-DOS by Microsoft in 1994. In 1990's Microsoft escalated an anti-competitive practice forcing computer manufacturers to lock in licenses to prevent competing operating systems from being used. The U.S. government Federal Trade Commission was already 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
MS-DOS 7 is the name given to the underlying DOS that Windows 95 and 98 run on. Every Windows 95 or 98 Boot Floppy Disk or Command prompt in a DOS-Window gives you access (through Command.com) to MS-DOS 7 internal commands.
Those commands are:
command cd (chdir) chcp cls copy copy con ctty date del (erase) dir exit lock md (mkdir) path prompt rd (rmdir) ren (rename) set time type unlock ver vol
MS-DOS 8 is the version associated with Windows ME (Windows Millennium Edition). Windows ME was the successor to Windows 98 SE and was targeted specifically at home PC users. Windows ME is a continuation of the Windows 9x model, but with restricted access to real mode MS-DOS. Windows ME broke many DOS programs and ended the line of Windows Operating Systems commonly considered to be DOS based.
Microsoft Windows was a layer running on top of MS-DOS for versions up to Windows ME. Not subsequent, but actually parallel to later versions of the MS-DOS based Windows Microsoft also developed a non-DOS based business oriented Windows line known as Windows NT. It is said to NOT use MS-DOS as its underlying base. Technically this is absolutely true, however, there remains elements of MS-DOS instruction within Windows NT.
Windows ME was the last version of Microsoft Windows built on the old MS-DOS layered architecture. All modern versions of Windows are built on Windows NT. Windows XP represented a new generation of NT based Windows that was capable of nearly full emulation of MS-DOS within its own command interpreter.
The Windows Command Shell provides access to a simulated MS-DOS environment. The command shell executing "cmd.exe," the command interpreter, is actually a Win32 console object. When you run the command prompt in your Windows XP, Vista, 7 you are running a Win32 program that runs within the Windows environment, which is built on the NT architecture, which underneath that still remains hacked MS-DOS code that is so deeply embedded that Microsoft and techno snobs continue to deny its existence, yet cannot remove it all without breaking Windows.
