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by skissane 1432 days ago
> CP/M was (mostly) written in the PL/M language and ran on the 8-bit 8080/Z80 processors. 86-DOS was written in pure assembly language and ran on the 16-bit 8086 processor.

In CP/M-80 1.x, most of the OS was written in PL/M. By the time we get to CP/M-80 2.x, the core of the OS (BDOS) has been rewritten in assembler for improved speed, while utilities (such as PIP) remain in PL/M.

CP/M-68K was written in C (although possibly with an earlier version in Pascal???). CP/M-8000 was written in C, probably ported from CP/M-68K.

CP/M-86 was mostly written in assembler, possibly with some bits (especially utilities) in PL/M and/or C as well.