Comments on: Doubling Univac’s Speed! http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/ Yesterday's tomorrow, today. Sun, 22 Nov 2009 11:04:18 -0800 http://wordpress.org/?v=2.8.4 hourly 1 By: mlines http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/comment-page-1/#comment-1052383 mlines Tue, 08 Apr 2008 18:36:03 +0000 http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/#comment-1052383 Core memory is immune to electromagnetic pulse (EMP). Back in the '70s I was shown core memory cards in equipment inside a missile defense command capsule. Core has less bytes per volume than other memory of the era, but it does no good in a war to have your memory wiped out by an EMP from a nuke. Core memory is immune to electromagnetic pulse (EMP). Back in the ’70s I was shown core memory cards in equipment inside a missile defense command capsule. Core has less bytes per volume than other memory of the era, but it does no good in a war to have your memory wiped out by an EMP from a nuke.

]]> By: Alan J. Richer http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/comment-page-1/#comment-1047874 Alan J. Richer Tue, 04 Mar 2008 21:06:56 +0000 http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/#comment-1047874 Unless it's deliberately demagnetized it won't erase. This is very unlike modern semiconductor memory (which is capacitor-based) where the locations have to be refreshed on a very short cycle to maintain their integrity. There was static semiconductor memory, but even that would lose its storage if power was removed. Yes, I know there were PROMs, EPROMs and other types of static semiconductor memory but these were never used as system memory as core was. Alan Unless it’s deliberately demagnetized it won’t erase. This is very unlike modern semiconductor memory (which is capacitor-based) where the locations have to be refreshed on a very short cycle to maintain their integrity.

There was static semiconductor memory, but even that would lose its storage if power was removed. Yes, I know there were PROMs, EPROMs and other types of static semiconductor memory but these were never used as system memory as core was.

Alan

]]> By: Charlie http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/comment-page-1/#comment-1047791 Charlie Mon, 03 Mar 2008 23:16:36 +0000 http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/#comment-1047791 My understanding is that one of the big advantages of core memory is that it's very hard to accidentally erase. It's not vulnerable to cosmic rays and such. That is one reason they used it for certain parts of the memory for the space shuttle. I remember reading somewhere that when the challenger blew up they reassembled the core memory (each ring was numbered) and read the data from the moment it exploded. My understanding is that one of the big advantages of core memory is that it’s very hard to accidentally erase. It’s not vulnerable to cosmic rays and such. That is one reason they used it for certain parts of the memory for the space shuttle. I remember reading somewhere that when the challenger blew up they reassembled the core memory (each ring was numbered) and read the data from the moment it exploded.

]]> By: Dillenger69 http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/comment-page-1/#comment-1047788 Dillenger69 Mon, 03 Mar 2008 23:01:08 +0000 http://blog.modernmechanix.com/2008/03/03/doubling-univacs-speed/#comment-1047788 What's spooky is that that very magnetic core memory was at the heart of the Sperry Univac cp890 I worked on in the late 80s and early 90s while in the navy. What’s spooky is that that very magnetic core memory was at the heart of the Sperry Univac cp890 I worked on in the late 80s and early 90s while in the navy.

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