19 Nov
2003
19 Nov
'03
11:31 a.m.
It was thus said that the Great Tom Jennings once stated:
I'm not sure how system calls are made in CP/M-86, but I do know that
there were two ways to call DOS functions, via INT 21h, and through a call
to location $005 (in the PSP segment), which emulates the CP/M system
calling convention (which I think just did an INT 21h/RET, although
gratefully the memory is fading on that stuff).
Heh.
-spc (Mommy! Make it go away!)
On Wed, 2003-11-19 at 16:24, Sean 'Captain Napalm' Conner wrote:
re: int 20h
If it was introduced in 1981, I would say work was done at the same time
that the IBM PC and MS-DOS were being worked on; if around 1982 it might
have been the design itself predated MS-DOS but that any changes to the
system might be too expensive and the designers felt it would be an easy
thing to work around in software.
Why was it short sighted? ... Since the
design was before MS-DOS,
Oh oh... was it really? Is it possible that my mental chronology is
corrupted? Gee, that's never happened before, erm, ugh...
when was the rainbow produced?
I don't recall exactly, I'd guess 1981 or 1982. Also, DEC was
primarily a minicomputer manufacturer so it may not be that
far fetched that engineers there might not be terribly familiar with state
of the art (hah!) microcomputer products at the time.
Well... I lack sympathy here, still; obviously they were building
machinery for this realm, it was beholden on them to know, as much as
was possible then of course. DEC was very arrogant about CP/M-86 being
superior; they told me as much many times. -spc (When
will this stuff dislodge from my brain? 8-)
Never, it just changes shape :-)