Re: Exciting times indeed!

Post #32,970 by dmarker2 3/21/02 4:46:00 AM 3/22/02 4:37:19 AM Reply	Re: Exciting times indeed! Tks for refresing my memory re Capacitive (vs Card). In the mod 30 the CROS cards were like puched cards (in size) & were created by running them through a punch (2540) to clip out the capacitors. They were inserted in a big steel box between air bags & a compressor was powered up to fill the air bags & press the Cards to the frames so as to get the capacitive effect. I did EC changes on Mod 40s & 30s & their I/O controllers (2841, 2400, 2848, etc) for 12 months straight from mid 1967 to mid 1968 - worked at nights on customers machines - in 12 months only blew-up one 2848 & temporarily clobbered a 2701 with a bad wire wrap. Most of the few problems we had were when faulty circuits that had been idle, got activated by an EC. We used to do SMS & SLT wire wraps. On SMS pins (1400 gear) we did hand wraps with a squeeze gun but on the 360 SLT pins we used a small hand wrap tool, but always tested the cicuits with the power delete gun. Also did lots of 'reaming' of land patterns using the power delete tool & as best I recall never got one wrong. Do those buzwords sound sweet ? SLT SLD DSLD ALDs RLDs EC Bill-of-Material & can you believe I still have the same engineers toolkit (with most of the origial tools) that was issued to me in 1967 (even have a pair of core memory tweezers). Cheers Doug Edited by dmarker2 March 22, 2002, 04:37:19 AM EST Expand All History
Post #33,098 by a6l6e6x 3/21/02 11:00:42 PM Reply	It is amazing you still have the tools. I bet you have one of those yellow handled wire strippers for SLT wiring work that looked like small needle nosed pliers. Engineers had to borrow those from CEs, the technician in our computer lab, or the guys on the manufacturing floor. All I have from those days is 360/67 reference card. And I didn't know that CEs replaced cores in core memory. I remember seeing core planes being assembled in Kingston. Tedious work done by women. Gosh, all those TLAs. Have not thought about them in a long time. Alex "Never express yourself more clearly than you think." -- Neils Bohr (1885-1962)
Post #33,118 by dmarker2 3/22/02 4:34:08 AM Reply	Re: You are dead right about replacing cores We field CEs never did to my knowledge. I just couldn't resist obtaining a pair of the tweezers from our tool store just to show people what they looked like. I have no idea why the tool store even had them. Being on night shift we had the power to apply for & obtain practically any tool in the inventory - we had by far the best toolkits of the entire field force. Funny story re cores - I remember a guy getting an award for about $US100,000 (a massive amount in the mid 1960s) for solving a core problem with hair spray. Cores being toroids would often try to spin on the x, y & sense lines when they got double pulsed (a flip-the-bit write), after some time a turning core could wear through the enamel coating on the wires & short them. This engineer suggested that all core memory be sprayed with hair lacquer which of course sealed them & stopped them turning. He saved the company so much in repairs that they awarded him a 'bundle'. Cheers Doug
Post #33,154 by a6l6e6x 3/22/02 12:05:52 PM Reply	Yep, I hear about that Suggestion Award. Alex "Never express yourself more clearly than you think." -- Neils Bohr (1885-1962)
Post #33,225 by static 3/23/02 4:27:03 AM Reply	Question about core memory. Just how physically big was a single ferrite core in core memory? A few cm? Or less than a mm? Or were there several sizes? Wade, who has never seen real core memory. "All around me are nothing but fakes Come with me on the biggest fake of all!"
Post #33,229 by dmarker2 3/23/02 6:44:19 AM Reply	Re: Question about core memory. - My memory of core :-) This was invented by An Wang (later of WANG fame) There were several (3?) different sizes for the cores. 1400 family (IBM) had one size - System/360 had at least 2 sizes. The smallest I recall were so small we needed fine pointed tweezers to pick one up. These had to be about 0.5 mm Alex can you add any info ? Doug
Post #33,242 by Ashton 3/23/02 2:02:01 PM Reply	Now imagine threading R/W wires x-turns, through EACH one..
Post #33,263 by a6l6e6x 3/23/02 8:24:14 PM Reply	Re: core memory. The [link\|http://www.science.uva.nl/faculteit/museum/CoreMemory.html\|Core memory] I remember seeing used cores about 2 mm outside diameter. I'm sure some were much smaller. I also remember seeing some made of a ceramic bobbin with a metal tape wound on it. These were quite large ~5 mm and used to perform logic functions. These I saw during a summer job with Burroughs (which later merged with Sperry Rand) to form Unisys. Alex "Never express yourself more clearly than you think." -- Neils Bohr (1885-1962)
Post #33,309 by static 3/24/02 9:23:26 PM Reply	Ah... I have a hazy memory of a work colleague showing me an exposed minature core-memory in the late '80s. It all makes sense now. Wade. "All around me are nothing but fakes Come with me on the biggest fake of all!"

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