[TUHS] Spider

[Jon Steinhart]

Paul Ruizendaal writes:
> 
>
> > I have vague memories here that maybe Heinz can help with if his are any better.
> > I believe that Sandy played a part in "the loop" or "the ring" or whatever it
> > was called that we had connecting our Honeywell 516 to peripherals.  I do
> > remember the 74S00 repeaters because of the amount of time that Dave Weller
> > spent tuning them when the error rate got high.  Also, being a loop, Joe
> > Condon used to pull his connectors out of the wall whenever people weren't
> > showing up to a meeting on time.  I don't know whether our network was a
> > forerunner to the spider network.
>
> It most likely was Spider - it became operational in 1972. The vist report that I linked to earlier also says:
>
> "The current system contains just one loop with the switching computer (TEMPO I),
> four PDP-11/45 computers, two Honeywell 516 computers, two DDP 224 computers,
> and one each of Honeywell 6070, PDP-8 and PDP-11/20. In fact many of these are
> connected in turn to other items of digital equipment.”
>
> It would be interesting to know more about the H516’s and Spider, any other recollections?

Ugh.  Memory lane has a lot of potholes.  This was a really long time ago.

I believe that the 516 network predated your quote above and was most likely
designed for the 516 as I'm pretty sure that Sandy was in our department; I
have some recollection of his office being in our block of rooms and of
spending some time talking to him.

I am guessing that one of these was installed in the UNIX lab but I
really don't know.  My guess is based on a recollection that there was a
GLANCE G up there, and the only interface to one of these was the network.
I can't imagine them not having a cool toy like the GLANCE G up there.
Maybe Doug or Ken remembers.

I also recall that the network was technically a Pierce Loop, named after
John Pierce of course.  My best recollection is that this ran off of the
DMA controller on the 516.  I think that it regularly sent a big block of
data around the loop.  That block had "holes" in it in which any "terminal"
device could say "hey, gimme some attention" or "here's some data".  I'm
using terminal here to mean any device other than the 516 that was moving
the bits around.  I have no memory of how collisions were handled or whether
there was any sort of bit-per-terminal device to avoid collisions.

The bits were sent around on coax.  They didn't go very far, and there were
repeater boards everywhere.  I don't recall any separate power supplies for
the repeater boards so maybe there was some DC on the coax for that.  The
repeater boards used 74S00s for drivers, and there was some sort of tuned
circuit that had an adjustment.  Every once in a while Dave Weller would
make the circuit with a scope and a little green screwdriver to keep things
working.

A day sticks out in my memory.  We were still in building 2 before buildings
6 and 7 were built and we moved to building 7.  The error rate on the network
went through the roof and became unusable, and I think when that happened the
516 crashed.  Wasn't a repeater, wasn't Joe pulling the plugs out of the wall.
Someone in a nearby lab had left a cover off of their cyclotron.  Can't express
how comforting that was; on par with discovering that the track on which I ran
in junior high school was a radioactive toxic waste dump or coming across family
photos of me in an open-pit Quebec asbestos mine as a kid.

I know that there were other instances of this network around the labs.  I did
a project that supported integrated circuit test systems in labs driven by a
single cost computer.  Yes folks, there was a day in which a computer cost more
than a wafer stepper :-)  This system was based on 516-TSS and the network.  It
sticks in my mind because I was working on it during the big Western Electric
debacle around the memory chip failures in the big new ESS installed in the
basement of the Chicago Sears Tower.

Anyway, that's all I can remember about this at the moment.  Heinz should know
something about it but his memory may be as bad as mine.  Another person who
would know is John Camlet.  Don't know if he's still around; a quick search
shows someone of about the right age living in Plainfield, NJ so if someone
lives out there try knocking on the door.

Jon