[Info-vax] OS implementation languages

[Dennis Boone]

 > That's seriously interesting thanks. So, contrary to what some are
 > saying, the idea of writing an OS in such a way was well established
 > by the mid-1970s.

The idea was fairly widespread quite a bit earlier, actually.  Burroughs
did ESPOL (an Algol derivative systems language) in starting in 1966.
IBM first described BSL in 1968; it evolved into PL/S, PL/X, etc, which
are still used in OS and VM.  The folks who founded Prime wrote a DOS
for the Honeywell x16 machines in 1968, and later used it as the basis
for their product in 1973.  CMU first released BLISS in 1970.

None of that means people quit doing things in assembler, of course, but
the writing was on the wall in the '60s.  CP/M first had a bunch of PL/1
derivative code, some of which which was later recoded in assembler.
BSL and PL/S notwithstanding, IBM still has a fair amount of assembler
in their stuff.

Jean Sammet wrote a paper on this sort of thing in 1971:

https://dl.acm.org/citation.cfm?id=807055

De