Editing MP/M (section)

==={{anchor|MP/M I|1.0|1.1|MP/M II|2.0|2.1}}MP/M-80===
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The 8-bit system required a [[8080]] (or [[Z80]]) CPU and a minimum of 32&nbsp;[[Kilobyte|KB]] of [[Random Access Memory|RAM]] to run, but this left little memory for user applications. In order to support reasonable setups, MP/M allowed for memory to be switched in and out of the machine's "real memory" area. So for instance a program might be loaded into a "bank" of RAM that was not addressable by the [[Central processing unit|CPU]], and when it was time for the program to run that bank of RAM would be "switched" to appear in low memory (typically the lower 32 or 48&nbsp;KB) and thus become visible to the OS. This technique, known as [[bank switching]] was subsequently added to the single user version of CP/M with version 3.0.

One of the primary uses of MP/M, perhaps to the surprise of DRI, was as a "power user" version of CP/M for a single user. The ability to run several programs at the same time and address large amounts of memory made the system worth the extra price.

'''MP/M II 2.0''' added file sharing capabilities in 1981,<ref name="DRI_MP/M-II_2.1_1982"/><ref name="MP/M_II_1981_UG"/><ref name="MP/M_II_1981_PG"/> '''MP/M II 2.1''' came with extended file locking in January 1982.<ref name="DRI_MP/M-II_2.1_1982"/>

Versions:
* MP/M 1.0 (1979)<ref name="MP/M_1981"/>
* MP/M 1.1<ref name="DRI_MP/M-II_2.1_1982"/> (January 1980)
* MP/M II 2.0 (July 1981,<ref name="MP/M_II_1981_UG"/><ref name="MP/M_II_1981_PG"/> added: file sharing)<ref name="DRI_MP/M-II_2.1_1982"/>
* MP/M II 2.1 (January 1982, added: extended file locking)<ref name="DRI_MP/M-II_2.1_1982"/>