16 Jan
2023
16 Jan
'23
4:20 p.m.
On 1/16/23 12:40, Paul Koning wrote:
On the CERL PLATO system at U of Illinois, around
1977, we had 20-ish
844-21 drives, and maybe a few 844-41 as well. Those were roughly the
same as the DEC RP04 and RP05 drives, same pack and track count.
Different sectors, though; 322 12-bit words per sector. Those are 3600
rpm drives, linear voice coil head actuator, dedicated servo surface.
The details of the format was handled in a sort of microcoded bit
handling engine, one of two engines in the programmable controller
(7054). I actually have the source code still around, and the manual
for that beast also still exists.
Most of our customers from that time had all of the drive farm as
well as the unit record equipment on MACs. (Predates Apple--Multiple
Access Controller). We kept Spence Preston busy... :
We had a 1311 on a CADET. Slow, but better than the alternatives (cards
or paper tape). Monitor IID, IIRC. Work cylinders were 0-25, IIRC.
No real file system, just DIM entries. I don't recall what options had
to be installed on a CADET to run Monitor, but I think indirect
addressing was a requirement.
My favorite was the CDC 6603/Bryant 4000. That bugger was engineered to
leak oil--it even had plastic jugs inside to collect the drippings. My
fondest memory was watching a COMSOURCE operator run to refill a 501
printer, hitting the Bryant oil patch and falling flat on his back...
--Chuck