PC compatible DOS
As a PC-compatible DOS are operating systems for computer called that compatible with the operating system standard MS-DOS from Microsoft are. These DOS operating systems are considered IBM-PC-compatible or MS-DOS-compatible if they can run on an IBM-PC or an IBM-PC-compatible computer and allow DOS or MS-DOS to be written for PC Run programs unchanged and fully functional.
DOS systems for home computers have their roots in mainframe operating systems that became available from the mid-1960s. At that time, magnetic disks replaced magnetic tapes as the most important mass storage device . Under the so-called disk operating systems , in contrast to the older tape operating systems, it was possible to process several program sequences ( batch jobs ) in parallel without IPL and thus to go beyond the purely sequential read / write processes of the tape drive , as for magnetic disks - Storage media is adequate.
With the group of systems that can run on the PC in the narrower sense (IBM-PC), the two branches of the DOS systems from Microsoft ( MS-DOS ) and IBM ( IBM DOS / PC DOS ) have emerged.
These DOS types were originally named QDOS in 1980, then soon renamed 86-DOS , by Tim Paterson of Seattle Computer Products as the CP / M- 80 derivative for Intel-8086 processors because the CP / M-86 Version of Digital Research was a long time coming. With the exception of the FAT file system, which was significantly improved compared to the CP / M file system and which Paterson had adopted from a BASIC interpreter from Microsoft, 86-DOS offered almost exactly the same possibilities as the CP / M-80, only for a newer one Processor type.
Shortly thereafter, 86-DOS was bought by Microsoft and renamed MS-DOS, when IBM asked Microsoft for an operating system for their IBM PC , which was under development , but Microsoft could not develop one itself quickly enough.
PC DOS and MS-DOS have therefore adopted some essential features and system interfaces ( APIs ) from CP / M. This fact later led to legal disputes between 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 varian