MP/M 8-16
| Company type | Operating system |
|---|---|
| Industry | Computer software |
| Founded | 1979 |
| Founder | Tom Rolander |
| Products | MP/M operating system |
MP/M (standing for Multi-Programming Monitor Control Program) was a multi-user iteration of the CP/M operating system, created by Digital Research's Tom Rolander in 1979. It allowed several users to access a single machine through individual terminals.
At the time, MP/M was a sophisticated microcomputer OS, incorporating a priority-based multitasking kernel (referred to as the nucleus) with features such as memory protection, simultaneous input/output processing (XIOS), and support for spooling and queuing. It enabled users to execute multiple applications concurrently and switch among them.
MP/M-80
This 8-bit variant required an Intel 8080 or Zilog Z80 processor and a minimum of 32 KB RAM, which constrained the available memory for programs. To address this limitation, MP/M implemented bank switching, allowing segments of memory to be dynamically mapped in and out of the CPU's address space—a method later incorporated into CP/M 3.0.
Interestingly, MP/M also gained traction as a single-user OS favored by "power users" due to its multitasking and enhanced memory management, which justified its premium cost.
The release of MP/M II 2.0 in 1981 brought file sharing functionality, while MP/M II 2.1 added advanced file locking capabilities in January 1982.
Versions include:
- MP/M 1.0 (1979)
- MP/M 1.1 (January 1980)
- MP/M II 2.0 (July 1981; introduced file sharing)
- MP/M II 2.1 (January 1982; extended file locking features)
MP/M-86
Following CP/M’s example, MP/M was adapted for the 16-bit Intel 8086 processor as MP/M-86 2.0 in September 1981. Among its primary developers was Francis "Frank" R. Holsworth, who later became Digital Research’s marketing director. Several updates to MP/M-86 2.0 were released by late 1981, succeeded by MP/M-86 2.1 in July 1982.
The version MP/M-86 2.1 merged components from CP/M-86 1.1 (BDOS 2.2) to form Concurrent CP/M-86 3.0 (BDOS 3.0) in late 1982, introducing enhancements such as "virtual screens." Kathryn Strutynski managed both CP/M-86 and Concurrent CP/M-86 projects. In December 1983, an optional DOS emulator called PC-MODE was launched for Concurrent CP/M-86 3.1 (BDOS 3.1), which shipped in February 1984. This platform eventually evolved into the MS-DOS-compatible Concurrent DOS (BDOS versions beyond 3.1), further developing into FlexOS and Multiuser DOS, systems still utilized in certain industrial environments.
Concurrent CP/M is commonly abbreviated as CCP/M.
MP/M 8-16
MP/M 8-16 (also known as MP/M-8/16) was CompuPro’s approach that combined multi-user, multitasking 8-bit MP/M with multi-user, single-user CP/M tasks on a multi-processor system using the 16-bit MP/M-86 architecture. This configuration later supported Concurrent DOS 3.1.
MP/M-286
In 1982, Digital Research announced plans for MP/M-286, designed to exploit the Intel 80286’s advanced memory management and protection capabilities for running MP/M-86 and CP/M-86 applications. Although this version was not released as initially intended, it evolved into Concurrent CP/M-286, which served as the precursor to Concurrent DOS 286 (released in 1985) and FlexOS 286 (released in 1986).
Commands
The Console Command Processor (CCP) for MP/M II includes support for the following instructions:
- ABORT
- ATTACH
- ASM
- CONSOLE
- DDT
- DIR
- DSKRESET
- DUMP
- ED
- ERA
- ERAQ
- GENHEX
- GENMOD
- GENSYS
- LIB
- LINK
- LOAD
- MPMLDR
- MPMSTAT
- PIP
- PRINTER
- PRLCOM
- RDT
- REN
- RMAC
- SCHED
- SDIR
- SET
- SHOW
- SPOOL
- STAT
- STOPSPL
- SUBMIT
- TOD
- TYPE
- USER
- XREF
CP/NET, CP/NOS, MP/NET, and MP/NOS
In the early 1980s, Digital Research introduced CP/NET, a networking technology designed to link an MP/M server with multiple CP/NET clients operating on CP/M, originally developed by Tom Rolander.
Building upon MP/M, CP/NET added network functionality enabling the system to act as both a server and requester in conjunction with CP/M client machines.
Diskless client setups were made possible through CP/NOS (Network Operating System) and MP/NOS, which eliminated the need for local storage by managing disk operations over the network.
These platforms enabled sharing of files and printers alongside electronic mail services.
The system comprised several essential components:
- NIOS – Network Input/Output System
- SNIOS – Slave Network Input/Output System
- NDOS – Network Disk Operating System
Versions 1.0, 1.1, and 1.2 of CP/NET were issued for 8080 and Z80 CPUs, while CP/NET-86 targeted the 8086 processor architecture.
Subsequent networking solutions developed from this foundation include DR Net and FlexNet.
Legacy
Beginning in 1997, Caldera permitted redistribution and modification of the original Digital Research CP/M and MP/M software packages, including their source code, through Tim Olmstead's "The Unofficial CP/M Web site." Following Olmstead's passing in 2001, Lineo—Digital Research's successor—broadened this license to encourage continued community-driven development.