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AVSIG Discussion Sections >> Hardware/Software

Ray Tackett
Top Gun


Reged: 04/30/04
Posts: 8892
Loc: Philadelphia, USA
Time sink!
      12/25/15 05:03 PM

Re 30cm nanoseconds,

Back in that day (1969-70), I worked on Burroughs' Iliac IV. It had four
quadrants of 64 procesors each. Each quadrant was fed work and sent output
to a Burroughs B5500, the second biggest system Burroughs made at the time.
The four B5500s were controlled by a B7700, the biggest there was.

The Iliac processors consisted of circuit cards plugged in to 2X2 foot
backplanes. The pulses were so short that the backplane wiring was done with
very thin 52 ohm coaxial cables. The cable lengths on the backplane had to
be tweaked to get the timing right. For example, the two inputs to a simple
AND gate had to arrive simultaneously or the gate's output could never be
valid. The delay time in the coax also brought up the issue of exactly WHEN
the gate had a valid output, which affected the lengths of other cables.

Then, there was the fun troubleshooting standing waves and ringing when one
or more of the tiny 52 ohm termination resistors went bad or missing.

Lotsa fun tech to that one, all of which became obsolete decades ago.

--------------------
Ray,

Owner, Lake Wood Be Gone

Turning quality lumber into sawdust and noise since 2013.

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Entire topic
Subject Posted by Posted on
* Time sink! Russell Holton 12/23/15 07:13 PM
. * * Time sink! Ray Tackett   12/23/15 10:18 PM
. * * Re: Time sink! Terry Carraway   12/24/15 05:48 AM
. * * Time sink! Ward Miller POU-NY   12/23/15 10:10 PM
. * * Re: Time sink! Terry Carraway   12/24/15 05:50 AM
. * * Re: Time sink! Russell Holton   12/24/15 12:49 PM
. * * Re: Time sink! Terry Carraway   12/25/15 06:16 AM
. * * Re: Time sink! Russell Holton   12/25/15 03:40 PM
. * * Re: Time sink! sreyoB yrraL   12/25/15 08:45 PM
. * * Re: Time sink! Ralph Jones   12/25/15 04:11 PM
. * * Time sink! Ray Tackett   12/25/15 05:03 PM
. * * Re: Time sink! Mase Taylor   12/25/15 05:49 PM
. * * Time sink! Ward Miller POU-NY   12/25/15 09:42 PM
. * * Re: Time sink! Russell Holton   12/26/15 03:57 PM
. * * Re: Time sink! John O'Shaughnessy [FCM]   12/26/15 03:16 PM
. * * Time sink! Ray Tackett   12/25/15 10:51 PM
. * * Time sink! Ward Miller POU-NY   12/26/15 11:19 AM
. * * Re: Time sink! Ralph Jones   12/26/15 12:30 PM
. * * Re: Time sink! Ralph Jones   12/25/15 09:37 AM
. * * Time sink! Ward Miller POU-NY   12/24/15 05:36 PM
. * * Re: Time sink! Russell Holton   12/24/15 06:10 PM
. * * Re: Time sink! Terry Carraway   12/25/15 06:19 AM
. * * Re: Time sink! Mase Taylor   12/25/15 11:01 AM
. * * Time sink! Ward Miller POU-NY   12/25/15 11:59 AM
. * * Re: Time sink! Ralph Jones   12/24/15 02:01 PM

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