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chrisshore
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re: Slideshow: A brief history of memory
chrisshore   12/5/2012 10:16:45 AM
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Not to mention the absolutely wonderful "rope memory" used in the Apollo Guidance Computer systems. A form of almost physically indestructible ROM in which the memory contents were encoded (literally "hard-wired") by weaving (by hand) the sensor wires in and out of a string of ferrite cores. Changing the contents of the memory meant unravelling the string and re-weaving the wires. http://en.wikipedia.org/wiki/Core_rope_memory

SylvieBarak
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re: Slideshow: A brief history of memory
SylvieBarak   12/5/2012 6:17:53 AM
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Lest we forget.... ;)

steveDS
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re: Slideshow: A brief history of memory
steveDS   12/4/2012 3:34:15 PM
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Pictures here: http://vipclubmn.org/Memory.html

steveDS
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re: Slideshow: A brief history of memory
steveDS   12/4/2012 3:06:09 PM
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Sperry Univac had a drum memory that was ~6 feet in diameter and ~18 inchs wide. Had a head per track so no moving parts except the drum. Because of the large diameter it did not have to rotate very fast to get a high speed at the R/W head

Kristin Lewotsky
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re: Slideshow: A brief history of memory
Kristin Lewotsky   12/3/2012 8:22:05 PM
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Apparently, I was having an out-of-body experience when I calculated 750 kHz--the actual figure is around 200 Hz. Good catch.

andyzg
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re: Slideshow: A brief history of memory
andyzg   12/1/2012 9:52:59 PM
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hmmm. in the mid 80ies there was a type of Intel memory that acted as SRAM, but upon power failure was able to write the whole array into EEPROM or Flash cells, in parallel, before power was gone. don't remember the name though...

Jack.L
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re: Slideshow: A brief history of memory
Jack.L   12/1/2012 8:58:20 PM
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Cool article by the way. There were a few technologies I had never heard of.

Jack.L
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CEO
re: Slideshow: A brief history of memory
Jack.L   12/1/2012 8:55:42 PM
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I actually "touched" magnetic core memory in the late 80's in a professional capacity. It was used in some Allan Bradley PLCs that were in an industrial plant I worked in as a student engineer. Hard to believe it was still in use as little as 25 years ago in functioning equipment.

Kevin Neilson
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re: Slideshow: A brief history of memory
Kevin Neilson   12/1/2012 2:20:54 AM
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This was really interesting. Good work. I'm dubious of one stat, though: it doesn't seem possible that the magnetic drum rotated at 750,000 rotations per second. In fact, that most definitely can't be true. Sometimes in my HDL code when I use a delay line or Johnson ring I call it a mercury line. It's the same concept. The springs in old reverb units are similar--they're basically FIFOs.

DResnick
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re: Slideshow: A brief history of memory
DResnick   11/30/2012 2:26:53 PM
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In addition to the magnetic core implementation shown, there were other variations according to the number of wires through each core. There were 2, 3, 4, and 5 wire varieties. In the 2-wire type, all the bits in a row are accessed at the same time. The Control Data Star-100 used this type of memory.

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