[TUHS] What would early alternatives to C have been?

[Luther Johnson]

I see, thank you for the history and clarification. The CP/M I have
worked with is CP/M 2.2. But as I said, the OS inside could have been
written in anything, and now I know in earlier versions, it was
something else, thank you.

On 03/09/2025 01:58 PM, Clem Cole wrote:
>
>
> On Sun, Mar 9, 2025 at 4:35 PM Luther Johnson
> <luther.johnson at makerlisp.com <mailto:luther.johnson at makerlisp.com>>
> wrote:
>
>     I believe CP/M was written entirely in 8080 assembly language.
>
> Not initially -- see below.
>
>     PL/M wasa PL/1 subset, I think Gary Kildall was the main
>     programmer behind that,
>
> Gary was a language person not an OS person.  PL/M was developed by
> him under contract with Intel for the original Intel 8080 development
> system.
>
>     and I'm sure there was a version for CP/M, but I doubt CP/M was
>     written
>     in it, just due to what I've seen of it.
>
> From the readme: https://github.com/brouhaha/cpm22
>
>     Introduced in 1974, CP/M by Digital Research was one of the first
>     microcomputer operating systems that was not tied to a single
>     computer vendor. It could be adapted to run on almost any 8080 or
>     Z80 microcomputer that had at least 16KB of RAM starting at
>     address 0000h.
>
>
>     Originally much of CP/M was written in the PL/M programming
>     language. With the introduction of CP/M 2.0, the command processor
>     (CCP) and kernel (BDOS) were rewritten in 8080 assembly language.
>
>     I have a port of CP/M for a
>     machine I've made and sold, where another programmer and I did the
>     porting work, and from what I've seen of early DOS and how it was in
>     many ways modeled after CP/M, it doesn't seem like CP/M was written in
>     anything other than 8080 assembly. However I've only seen the BIOS
>     (not
>     IBM PC BIOS, but the original coining of the term for CP/M,
>     standing for
>     "basic input/output system"),
>
> Again, the term came from the Intel 8008 development system.
>
>     so on the other side, inside of CP/M, I
>     guess it might be anything, but it seems like it is most likely 8080
>     assembly language too.
>
>
> As a compiler guy, Kidall was once quoted as the reason who originally
> wrote CP/M to sell more copies of his compiler.
> ᐧ

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