16 Mar
2023
16 Mar
'23
5:03 a.m.
The 709x had data channels which ran asynchronously, and generated channel traps — i.e.
interrupts. I don’t think it had a, say, 60Hz clock, but I/O interrupts would allow a
certain basic level of multiprogramming. The IBM 1410 also had I/O interrupts, and even
had a rudimentary optional teleprocessing supervisor. IBM turned some 1410s into a basic
message switching system.
Sent from my iPad
On Mar 15, 2023, at 19:23, Jon Elson via cctalk
<cctalk(a)classiccmp.org> wrote:
On 3/15/23 18:32, Paul Koning via cctalk wrote:
Apart from spooling, which uncouples slow I/O from execution, there is also
"multiprogramming", which means being able to run more than one job
concurrently. Timesharing does that, of course, but I think multiprogramming was intended
to refer to batch systems that did so.
Yes, the IBM 709x ran in single-job fashion. I don't think it had
interrupts, so breaking off one program to schedule another was not possible. Also, it
had no memory protection. We had a 7094 at Washington University in the late 1960s, and
it was the main computer resource on campus. When the moved up to a 360/50, they were
able to benefit from multiprogramming, and got a boost in throughput, although the 7094
was QUITE a bit faster than the 360/50.
Jon