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Computers: Everything Old Is New Again!

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Well this one snuck up on me. I didn't know anyone was working on minitiarized magnetic memory.

At my first job the only computer we had had Iron Core Magnet Memory, 64K of RAM and was a 32 bit word (processor). It interfaced with various pieces of equipment and integrated the data. The memory modules were built up of tiny ferrite toroids (doughnuts) with intersecting copper wires threaded through them in X, Y grid fashion. Each bit was read or written by passing a current thru the appropriate toriod, low current to read, high current to write. Memory couldn't hold all the routines we needed, so we would have to manage the memory usage by loading and unloading 'overlays' of different sizes from magnetic tape, which took several minutes.

The modules were about 1 inch thick, 1 foot high and about 18 inches deep. And they were heavy, probably 20 lbs. The whole thing was quite fast for those days IF......you could keep it from over heating. If it overheated and we didn't have time to wait for it to cool by ventilation, the techs were known to pull memory modules and put them in the freezer for a while.

When it overheated you would start losing functions randomly depending on which memory modules were overheating. This meant you had to be creative in figuring out how to keep processes going, since you didn't know what buttons would work. Fortunately there was usually more than one way to skin a cat.

All this stuff was probably mid 1960's technology. Anybody else remember dinosaur technology?


DALLAS - Achieving a long-sought goal of the $48 billion memory chip industry, Freescale Semiconductor Inc. announced the commercial availability of a chip that combines traditional memory's endurance with a hard drive's ability to keep data while powered down.

The chips, called magnetoresistive random-access memory or MRAM, maintain information by relying on magnetic properties rather than an electrical charge. Unlike flash memory, which also can keep data without power, MRAM is fast to read and write bits, and doesn't degrade over time


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I remember working on a PDP-11 that had 'piano keys' to load the startup code byte by byte. Address, word, latch, address, word, latch etc. Turn big key to 'run' and watch the paper tape start up. Unless you'd set a switch wrong.

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