18 Jan
2017
18 Jan
'17
12:53 p.m.
On 17/01/17, Dan Cross wrote:
A question about 36 bit machines....
In some of the historical accounts I've read, it seems that before the
PDP-11 a pitch was made for a PDP-10 to support the then-nascent Unix
efforts. This was shot down by labs management and sometime later the
PDP-11 arrived and within a decade or so the question of byte width was the
creatively settled for general purpose machines.
The question then is twofold: why a PDP-10 in the early 70s (instead of,
say, a 360 or something) and why later the aversion to word-oriented
machines? The PDP-7 was of course word oriented.
I imagine answers have to do with cost/performance for the former and with
regard to the latter, a) the question was largely settled by the middle of
the decade, and b) by then Unix had evolved so that a port was considered
rather different than a rewrite. But I'd love to hear from some of the
players involved.
Doesn't exactly answer your question, but from the "Oral History of Ken
Thompson":
Q: As I recall this - once upon a time weren't you trying to get a
PDP-10 or something like that for the lab?
Ken Thompson: Yes, we were arguing that the Multi[cs] machine should be
replaced with a PDP-10. And there was such a huge backlash from
Multi[cs] that it was pretty soundly turned down. It was probably a good
idea, the -10 is a kind of trashy machine with 36 bits - the future just
left it behind.
"the -10 is a kind of trashy machine with 36 bit"
I'm not sure whether I can still like UNIX now :( I hope this is the bad
(?) experience with Multics on the GE-645 speaking.
"the future just left it behind"
More like DEC didn't want internal competition with the VAX.
aap