14 Sep
2007
14 Sep
'07
6:16 a.m.
Subject: Re: 8-bitters and multi-whatever
From: "Chuck Guzis" <cclist at sydex.com>
Date: Thu, 13 Sep 2007 15:59:59 -0700
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>
On 13 Sep 2007 at 17:36, Roy J. Tellason wrote:
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.
Most MAC setups again were master/slave. An example was BOCES/LYRICs
PDP-10/TOPS-10 timeshare system that had a PDP-8I as the comms frontend
(switch). The PDP-8 served as an intelligent peripheral but it's
dectapes were not available to the 10.
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. 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
that "networking".
Mostly because it was a clear master slave lashup. Generally/loosely
networking implied more than two machines and a more general ability
to transfer/communicate as needed be it files, shared devices or some
combination of both with any machine being able to initiate and
communicate as a peer to others that could do same or similar.
Allison
17 Sep
17 Sep
12:24 a.m.
On 14 Sep 2007 at 9:16, Allison wrote:
Most MAC setups again were master/slave. An example
was BOCES/LYRICs
PDP-10/TOPS-10 timeshare system that had a PDP-8I as the comms frontend
(switch). The PDP-8 served as an intelligent peripheral but it's
dectapes were not available to the 10.
Not at all. CDC 6681 or 6684 DCCs could be equipped with a MAC to
control the 3000-series peripherals. The reservation was a positive
interlock accessible from either machine. Very common for sharing
printers--the two machines didn't even have to be running the same
OS, although it was useful when they did--but they needed some sort
of communications mechanism. In TCM, we used shared ECS for this--I
think NOS/BE did also. Often one could simply manually function the
proper channel through DSD to grab a printer for a bit, before the
operator at the next machine looked over and said "Do you have my
printer?". Deadstart tapes usually had both printers/tapes etc. in
the EST.
Mostly because it was a clear master slave lashup.
Generally/loosely
networking implied more than two machines and a more general ability
to transfer/communicate as needed be it files, shared devices or some
combination of both with any machine being able to initiate and
communicate as a peer to others that could do same or similar.
The CDC 6682/6683 Satellite coupler was a 6000 series channel-to-
channel interace. Mostly used for data transfer between systems, but
it was not very common. Easier to do this with ECS. This was WAY
before ethernet (1964).
Cheers,
Chuck
Allison
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