8-bitters and multi-whatever
cclist at sydex.com
Thu Sep 13 17:59:59 CDT 2007
On 13 Sep 2007 at 17:36, Roy J. Tellason wrote:
> > And I'd also disqualify device-sharing, such as a MAC (multiple
> > access controller) between an I/O device and two computers. Those go
> > WAY back...
> I'm not familiar with such stuff.
Ah, showing my age. "Back in the day" you might have two otherwise
independent mainframes and, say, two printers. To have a system do
nothing but wait for a print job to finish while only one of the
printers was busy is a huge waste of resources. A card punch might
be an infrequenly used piece of equipment, so why have two? Or a
printer could be offline for maintenance, but why take the machine it
was attached to down also? Or, instead of having two banks of 8 tape
drives for two machines, why not whittle that down to, say 12, and
allow the drives to be shared? IIRC, most vendors offered some sort
of a MAC facility, even if it was a QSE. CDC certainly did.
Of course, direct coupling of computers was also done, either via a
special I/O device or even shared bulk core. But we never called
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