Multiuser DOS

Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers.

An evolution of the older Concurrent CP/M-86 and Concurrent DOS operating systems, it was originally developed by Digital Research and later acquired and further developed by Novell. Its ancestry lies in the earlier Digital Research 8-bit operating systems CP/M and MP/M, and the 16-bit single-tasking CP/M-86 which evolved from CP/M.

When Novell abandoned the system, the three Master Value Added Resellers (VARs) Datapac Australasia, Concurrent Controls and Intelligent Micro Software took over and continued independent development into Datapac Multiuser DOS and System Manager, CCI Multiuser DOS, and IMS Multiuser DOS and REAL/32.

Concurrent CP/M-86

The initial version of CP/M for the IBM PC, CP/M-86, was commercially unsuccessful, as Microsoft's MS-DOS offered much the same facilities for a considerably lower price. Like MS-DOS 1.0, CP/M-86 did not fully exploit the power and capabilities of the new 16-bit machine.