-----Original Message-----
From: cctalk-bounces at
classiccmp.org
[mailto:cctalk-bounces at
classiccmp.org] On Behalf Of Mike Loewen
Sent: 07 March 2012 22:51
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: In defense of wire-wrap; was: Cosmac Elf on breadboard
On Wed, 7 Mar 2012, Dennis Boone wrote:
Another production unit that shipped with lots of
wire-wrap
on board was
the IBM 3803 tape controller. E.g. from
Pat's collection:
http://computer-refuge.org/compcollect/ibm/3420/3803-back-open
-small.jpg
The central computer (Hughes H5118ME) of the AN/FYQ-93
air defense
system had a slightly larger backplane, all wire-wrapped. It didn't
generally cause problems, unless someone was fooling around
in the back.
It took us 5 days to track down a connection problem on the backplane
once, eventually doing point-to-point continuity checks.
Machine produced wire wrap is extremely reliable. The wire forms a cold weld
round the sharp corners of the post. I think the most common problem was a
wire being strung too tight and an extra contact being created when a post
rubbed through the insulation.
Most mainframes of the 60's had large quantities of wire wrap. We had a
Honeywell L66 (basically an slightly upragde GE600//6000). It had I guess
about 100 12" square boards which were wire wrapped on the back. The back
plane these fitted into was also wire wrapped. Some was produced completely
automatically on cnc driven machines
Mike Loewen mloewen at cpumagic.scol.pa.us
Old Technology
http://sturgeon.css.psu.edu/~mloewen/Oldtech/