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Slideshow: A brief history of memory

11/29/2012 07:15 AM EST
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EREBUS0
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re: Slideshow: A brief history of memory
EREBUS0   11/29/2012 8:32:51 PM
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Memory and disk space will both expand to overflow existing technology. At the time Bill made his statement, few of us had ever used more than 64K bytes of memory. It was only after memory prices fell that the great explosion began. I remember when 8K by 16 bits cost $1/bit. Compare that to today's costs and you can see why Bill assumed the growth of memory would be limited. By the way, I have a 16K by 16 bit ferrite bead board framed in my living room as an example of the past example of memory technology.

sframboss
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re: Slideshow: A brief history of memory
sframboss   11/29/2012 10:21:45 PM
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Ferroelectrics, a "new" non-volatile memory technology on today's scene, actually competed for the "core" memory of new processors in the 1950's. See the work of J. R. Anderson of Bell Labs: [ J.R. Anderson, "Ferroelectric Material Storage Element for Digital Computers and Switching Systems." Electrical Engineering, Vol. 71, pp. 916-922, October, 1952. ], Charles S. Pulvari of the Catholic University of America: [ AIEE-IRE '53 (Western) Proceedings of the February 4-6, 1953, Western Computer Conference Pages 140-159, ACM New York, NY, USA ©1953 ], and Dudley A. Buck at MIT: [ Dudley A. Buck, "Ferroelectrics for Digital Information Storage and Switching", Report R-212 a Master's Thesis, May 16, 1952, MIT ]. Their devices used bulk ceramic capacitors, not thin films so they required hundreds or even thousands of volts to switch the capacitors. Something old! Something new!

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.

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.

Jack.L
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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.

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.

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...

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.

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

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

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