[TUHS] A/UX [was Linux is on-topic]

[William Cheswick]

The wire lengths were important in CDC CPUs. I once saw an expert from CDC poking through the rats nest of wires on the backplane, yanking the wires around with his flashlight, and pulled one out thinking it was the wrong length.  It was.

Message by ches. Tappos by iPad.


> On Aug 14, 2020, at 11:08 PM, Andrew Hume <andrew at humeweb.com> wrote:
> 
> not on the cyber 72 we shared, dave.
> it was, in fact, a length of wire.
> the 72 had one length, and the 76 had a shorter length.
> (i guess you could call that a sort-of timing capacitor?)
> 
> i watched a cyber technician change the wires for the
> purposes of doing a verification test.
> 
>> On Aug 14, 2020, at 7:02 PM, Dave Horsfall <dave at horsfall.org> wrote:
>> 
>>> On Fri, 14 Aug 2020, Rich wrote:
>>> 
>>> On a vaguely related note, I found it amusing that there was a well known hack for Cray's (or perhaps 6600's) which were misbehaving: put a Tektronix scope probe on a test point that generally had one there during final system checkout. The load (extremely mnimal by design) was just enough to stabilize the system.
>> 
>> There was also the story about the major difference between a Cyber 72 and a Cyber 73 was just a timing capacitor...  Very expensive capacitor :-)
>> 
>> -- Dave