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

[Warner Losh]

On Sun, Mar 9, 2025 at 2:59 PM Clem Cole <clemc at ccc.com> wrote:

>
>
> On Sun, Mar 9, 2025 at 4:35 PM Luther Johnson <
> 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.
>

Isn't that what Unix did for C
<duck/>

Warner

> ᐧ
>
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