[1] : The Free On-line Dictionary of Computing (27 SEP 03)

ferrite core memory
     
         or "core" an early form of non-volatile storage
        built by hand from tiny rings of magnetisable material
        threaded onto very fine wire to form large e.g. 13"x13" or
        more rectangluar arrays.  each core stored one bit of data.
        these were sandwiched between printed circuit boards?.
        sets of wires ran horizontally and vertically and where a
        vertical and horizontal wire crossed, a core had both wires
        threaded through it.
     
        a single core could be selected and magnetised by passing
        sufficient current through its horizontal and vertical wires.
        a core would retain its magnetisation until it was
        re-magnetised.  the two possible polarities of magnetisation
        were used to represent the binary values zero and one.
     
        a third "sense" wire, passed through the core and, if the
        magnetisation of the core was changed, a small pulse would be
        induced in the sense wire which could be detected and used to
        deduce the core's original state.
     
        some core memory was immersed in a bath of heated oil to
        improve its performance.
     
        core memory was rendered obsolete by semiconductor memory.
     
        for example, the 1970s-era ncr 499 had two boards, each with
        16 kilobytes of core memory.
     
        1996-03-04
     
     
see also:
non-volatile storage bit printed circuit boards semiconductor ncr 499 kilobytes 

Ferrite >> F Words
Ferrite, definition of term: Ferrite
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Core >> C Words
Core, definition of term: Core
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Memory >> M Words
Memory, definition of term: Memory
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Core Dump >> C Words
Core Dump, definition of term: Core Dump
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Flash Memory >> F Words
Flash Memory, definition of term: Flash Memory
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Main Memory >> M Words
Main Memory, definition of term: Main Memory
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Expanded Memory >> E Words
Expanded Memory, definition of term: Expanded Memory
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Edo Memory >> E Words
Edo Memory, definition of term: Edo Memory
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Cache Memory >> C Words
Cache Memory, definition of term: Cache Memory
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Extended Memory >> E Words
Extended Memory, definition of term: Extended Memory
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