n Microsoft and the CP / M manufacturer Digital Research.
PC compatible DOS
MS-DOS is an operating system that was developed at Microsoft for IBM. The first version of MS-DOS distributed by Microsoft itself came onto the market in 1982 as MS-DOS 1.25. MS-DOS was available in adaptations for dozens of different PC manufacturers (OEMs) , in which
IO.SYSthe hardware-related input and output routines in the file as well as various auxiliary programs specifically adapted to the particularities of the respective host machines, which are compatible with the 8086 processor from Intel, but not necessarily also had to be compatible with the IBM PC. These adapted versions could therefore not be run on computers from other manufacturers or only to a limited extent. The OEM variant of MS-DOS specially adapted to IBM PCs was called IBM DOS or later PC DOS and was sold by IBM for its own computers. The technical further development took place alternately at both Microsoft and IBM.
With the advent of "100% IBM-compatible" clones from 1983 and the disappearance of non-IBM-compatible x86 computers, the functionally specially adapted OEM versions of MS-DOS also increasingly disappeared from the market, so that in the further course all OEMs also a generic MS-DOS version could be operated with only minimal OEM adaptations, which often only consisted of adapting the start message and / or in individually added utilities. Compared to the OEM version "PC DOS" sold by IBM, the generic version of MS-DOS at least had code for handling various special cases on machines that were not completely compatible. PC DOS as a dedicated operating system only for original IBM machines could do without these special treatments and thus remained somewhat leaner and more powerful.
The last independent MS-DOS version with the version number 6.22 appeared in 1994. As part of the operating systems of the Windows 9x series, MS-DOS received LBA and FAT32 support and was further developed up to version 8.0.
IBM DOS and PC DOS
PC DOS is a widespread OEM variant of the MS-DOS operating system, which arose at Microsoft as a result of an order development for IBM and which was subjected to slight changes, above all to a large number of bug fixes, by IBM before delivery. Version 1.0 came onto the market in 1981, before the first MS-DOS version distributed by Microsoft itself, under the official name "IBM Personal Computer Disk Operation System 1.0", but was even then simply called "PC DOS" for short. The versions 3.30 to 5.02 ran under the official name "IBM DOS" and from version 6.1 the system was marketed as "IBM PC DOS".
Compared to generic MS-DOS editions, PC DOS had various optimizations. Some of them could only run on original IBM PCs and 100% compatible machines. The technical further development took place alternately at both Microsoft and IBM.
PC DOS was further developed to be compatible with MS-DOS (Windows 3.x) up to version 6.3 from 1993, whereby version 6.1 of MS-DOS 6.0 already differed more clearly than the previous versions and PC DOS was also marketed as an alternative for PCs from other manufacturers has been. The current versions PC DOS 7.0 (Revision 0, 1994) with REXX , PCMCIA , DPMS and XDF support, Stacker Disk Compression and a powerful text editor and help system, PC DOS 2000 (PC DOS 7.0 Revision 1, 1998) with year -2000 -Fixes and Euro support and OEM PC DOS 7.1 (2003) with LBA / FAT32 support are independent further developments by IBM, in which Microsoft no longer played a part.
DR-DOS (up to and including version 6.0 still DR DOS ) was originally developed by Digital Research as an answer to MS-DOS, since MS-DOS, originally a clone of CP / M-80 for 8086 processors, was contracted with IBM advanced to become the standard operating system for the IBM PC and the large market of compatible computers. Such a supremacy among the operating systems for microcomputers was previously held by Digital Research's CP / M operating system family, which has now been increasingly replaced by MS-DOS. DR-DOS can be seen as a further development of CP / M (here e