rpw3@fortune.UUCP (02/22/84)
#R:rlgvax:-173400:fortune:28000010:000:882
fortune!rpw3 Feb 21 19:38:00 1984
Sorry, Guy, your comments on disks are well said, but... The Mac's
hardware is no less suited to multi-tasking than the IBM PC's is
(which I agree isn't saying all that much).
There is no problem, in principle, with requiring PC-relative
code from the "C" compiler, and then just using the register
context as the "MMU". Even if you don't do that, you can make
the compiler use some register(s) as "base" registers (anybody
for a7/a6 = "stack"/"stackframe", a5 = "text", a4 = "data" iff
"split I/D" ??).
No, it is not convenient, but it is also NOT slow. Look at "xxx" vs. "xxx(a5)".
From one who used to run MANY-tasked network nodes including
"virtual hosts" on the lowly PDP-8 (with NO index registers)...
Rob Warnock
UUCP: {sri-unix,amd70,hpda,harpo,ihnp4,allegra}!fortune!rpw3
DDD: (415)595-8444
USPS: Fortune Systems Corp, 101 Twin Dolphins Drive, Redwood City, CA 94065emjej@uokvax.UUCP (03/05/84)
#R:rlgvax:-173400:uokvax:3400036:000:170 uokvax!emjej Feb 29 16:37:00 1984 Gee--all that means is that what you would run on the Macintosh is OS-9/68000 Level One. Agreed that Unix(tm) requires vastly more resources, though... James Jones
rpw3@fortune.UUCP (03/25/84)
#R:wu1:-25100:fortune:28000015:000:791
fortune!rpw3 Mar 24 21:51:00 1984
I may be answering an article that I have answered before (due to the
decwrl-amd70 logjam), but it applies to "multi-tasking" (which has come
up lately) as well as to "timesharing":
NOTICE: The Mac hardware is no less and
no more "unsuited to timesharing"
than is the IBM PC or XT.
The PC runs UNIX: PC/IX, Venix, Coherent [fudging "UNIX"], take your pick.
Whether anyone will choose to do the hard work to get UNIX running
on "yet another machine for which you have to use the general registers
as an MMU" [my phrase] is an open question.
That it is possible, and that it could run at quite a good clip, is not.
Rob Warnock
UUCP: {sri-unix,amd70,hpda,harpo,ihnp4,allegra}!fortune!rpw3
DDD: (415)595-8444
USPS: Fortune Systems Corp, 101 Twin Dolphin Drive, Redwood City, CA 94065