8 Oct
2022
8 Oct
'22
7:36 a.m.
-----Original Message-----
From: Jon Elson via cctalk <cctalk(a)classiccmp.org>
Sent: 08 October 2022 03:10
To: ben via cctalk <cctalk(a)classiccmp.org>
Cc: Jon Elson <elson(a)pico-systems.com>
Subject: [cctalk] Re: Bendix G-15 Restoration
On 10/7/22 18:14, ben via cctalk wrote:
I know the Ferranti Pegasus which is/was a serial machine everything was clocked to the
drum. If the drum failed there was a special set of hardware to re-write the clock track.
Whilst replacing the clock would not have been hard, I don't think adding core would
have helped there because everything was so integrated.
.. it used delay lines for registers which ran at the same speed so everything just
worked...
On 2022-10-07 1:09 p.m., paul.kimpel--- via
cctalk wrote:
Tghe G-15 was a serial computer with an 90 KHz bit clock. The entire
organization of teh computer revolved around the drum (pun intended). There
was an optimizer that organized instructions around the drum so that the next
instruction came up on the read head just as the last instruction
finished. Without tearing the entire machine apart and redesigning the logic,
core would not make it faster.
We'd all like to see the ALGO compiler, but
be forewarned
-- it's something like 14 passes on paper tape, with intermediate
results punched on paper tape. I understand it's a bit more
convenient to use if you have magnetic tape drives, but it's still
going to be slow -- there's only so much you can do with 2K words of
memory.
Trying to hide the fact the drum makes it slow.
Did any one ever replace the drum with core memory, on the early
serial computers?
Ben.
The PDP-8S did have core memory, and for a bit serial
computer, it was fairly
fast.
For calculation, I believe the G-15 was fast. I can't believe any one would seriously
run a high level compiler on such a machine.
Jon
Dave