17 Jul
2018
17 Jul
'18
2:07 a.m.
On Jul 16, 2018, at 4:53 PM, Clem Cole <clemc at
ccc.com> wrote:
On Mon, Jul 16, 2018 at 4:36 PM, Johnny Billquist <bqt at softjar.se> wrote:
Last version of PDP-11 Pascal is V1.3, released 1989. And it bears a strong resemblance
and compatibility with VMS Pascal
?I believe you, I was not certainly not following it in those days, I'll ask Leslie
what the scoop was. I believe she was still managing TLG then, if not she certainly knows
who was.
As Paul K said, the other languages were not hard, but it was they had a couple of
issues, the big one being address space.
Address space? For most high level languages, addressing is abstracted so this
doesn't enter into the language at all. C is somewhat special here because it's
really a low level language pretending to be high level. But Algol, Pascal, and others
don't care at all how big your addresses are.
There was a comment that Pascal was taking over, that seems somewhat plausible. By the
mid 1970s Pascal was emerging and Algol 60 was the old thing. Algol 68 was quite capable
but not so easy to implement, partly because the specification was very rigorous and
therefore not so easy to understand.
I remember looking at the generated machine code from VMS Pascal V1.0. My impression was
that it was a CDC Pascal compiler, slightly tweaked to output VAX machine code.
"Slightly", because the code sequences looked exactly like what you'd expect
from a load/store machine like the CDC 6600, and not at all like what you'd use on a
machine whose arithmetic instructions can go directly to memory.
paul