9 Mar
2025
9 Mar
'25
8:35 p.m.
I believe CP/M was written entirely in 8080 assembly language. PL/M was
a PL/1 subset, I think Gary Kildall was the main programmer behind that,
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. 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"), 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.
On 03/09/2025 01:13 PM, John Levine wrote:
It appears that Dan Cross <crossd(a)gmail.com>
said:
My short list included PL/1, Algol/W, Fortran,
and Pascal. Fortran was
already mentioned. I don't think PL/1 (or PL/I) could have fit on
those machines. ...
There were a lot of PL/I subsets or variants used for system
programming. Intel had PL/M, used to write CP/M. IBM had PL/S, used to
write some parts of OS/360, and reimplemented at RAND in the early
1970s. XPL was writeen at Stanford in the late 1960s, intended for
writing compilers with a small one-pass compiler written in itself.
PL/360 was sort of PL/I-ish although it was really an IBM 360 assembler with
Algol like syntax, used to write Algol W.
One of these could have been a reasonable basis for a system language, but I
don't think the result would have been any better than C.
R's,
John