Carl:
> Since they are connected to disk drives,
> they should have an 1133 connected to each 1131.
I wish I had photos of the 1133 mux I used.
It was mostly empty: just the minimal gates required for
two single platter drives.
Quite the closet!
> That box is where the 1130 would implement the selector channel
> which provides the bus and tag connection to 2310 and 2311
> in a supported 1130 system (and to other bus and tag based disk controllers
> for the disks they are supporting in the factory).
Does that mean the controller translates the 1130's XIO instruction
into the bus-and-tag commands?
One of the 2 System 1130s donated to my college (around 1980)
had a Calcomp DS-12 diskpack that connected directly to the SAC.
It used an 11 platter diskpack for 20 surfaces,
each surface emulating one drive.
It emulated 5 drives at a time in compatibility mode.
I never had the software to access more than 5 surfaces at a time.
I wish the manual had survived for it would've been a great start
for how to emulate ALL the hard drives with one unit
(a 4004 based controller at the time).
Did IBM ever have a similar device?
That system had 2 Calcomp peripherals: the 565 plotter (IBM 1627)
and the DS-12.
> As for boot up, they could have some custom gear,
> other than a 1442 or 2501
I thought there was a jumper for booting from paper tape,
which might also beat the 80 word limit.
And if it read 2: 8 bits for each word, then no need for
expanding the 12 bit card column into a 16 bit word.
-- jeff jonas