Re: Real core

[Bob Shair]

At 09:32 AM 10/8/2006, you wrote:

According to some Computer Science class notes from the mid 1990s found here:
http://www.google.com/url?sa=t&ct=res&cd=1&url="">

a megabyte of 3090 memory cost $19,200. That works out to $0.018311/byte  (1 MB = 1024 * 1024 bytes).

The voice of reality speaks up.  Of course the cost of core dropped dramatically over time.
                 Price history of magnetic core memory

http://www.science.uva.nl/museum/CoreMemory.html                  1960     .20/bit
                                                                       1974     .01/bit

The price per bit of core memory was 20 dollarcent in 1960 and decreased from there with 19% per year. In 1974 was the 'turn-over' to semiconductor (transistor) memory with the advent of the 4 kbit chip; the cost was 1 cent per bit for both techniques by then.

http://socdesign.blogspot.com/2005/12/lessons-of-history.html    1969    .04/bit

Intel’s first MOS memory, the 256-bit 1101 static RAM (SRAM), was too slow and expensive when it was introduced in September, 1969. At 20-60 cents/bit, it was 5x to 12x more expensive than core memory per bit.

http://www.fourmilab.ch/documents/univac/config1108.html         1968     .05/bit

Univac 7005-72  131 K word Core Memory  $823,500

Phil Smith III said:
Ok, this is obscure to the max, but: ISTR real core costing $1/byte. 
Someone else says:
"$1 a byte was extrordinarily cheap for 1971. Ferrite core was going for up to $2 per BIT."
Of course, he then goes on to talk about PDPs, so maybe he's talking about core made in Maynard instead of Mexico...
Anyway: do any of the other old-timers remember anything about this?

Bob Shair
Open Systems Consulting
Champaign, Illinois