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From "Digital at Work" , Digital Press, copyright 1992, page 25
An Innovation in
Computer Memory
In the early years of Project Whirlwind, Jay Forrester recognized the limitations of the
computer memory systems then available. Electrostatic storage tubes, magnetic
drums, tapes, and disks lacked the speed and reliability required for the project. With
Forrester's invention of random-access
coincident-current core memory, information could be extracted immediately rather
than searched for sequentially on tapes or disks.
Working with graduate student Bill Papian, Forrester's invention led to an array of ferrite
magnetic materials for storing information. In his thesis, entitled "A Coincident-Current
Magnetic Memory Unit" (1950), Papian described magnetic core memories,
honeycombs of minute magnetic cores strung on wires, through which storage
information was read to electronic circuits in the computer. This invention provided the
speed and reliability the project required.
The first bank of core memory was installed in the Whirlwind on August 8, 1953.
Computing speed doubled, and useful operating time increased to more than
90 percent. The same year, Raytheon, Remington Rand, and RCA
shifted commercial machine storage emphasis to
magnetic core storage, followed a year later by IBM. Although initially unappreciated
except by the engineers, scientists, and researchers working on this new technology,
its impact on the history of computing would be great.
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From Dr. Mike Williams, Curator of the
Computer History Museum
Folks,
While I was away in LA I managed to talk to a man who ran a core memory
company. He indicated that there were only a couple of firms that were in
the business of suppling OEM core memories and that many many computer
companies used these rather than try and make them for themselves.
The major players were:
- FABRI-TEK owned by a Mike Nicholson in Minneapolis
(didn't make cores, but only assembled them)
- Telemeter Magnetics (TMI) - later purchased by AMPEX
(based in LA - both made cores and assembled them)
- General Ceramics (held some of the patents on cores) in N.J.
- Core Memories Limited (CML) in Ireland - an offshoot of DataProducts Ltd
- Electronic Memories Inc. (EMI) and offshoot of Ampex.
Now if your core plane has TM on it, then I assume that it must be made by
Telemeter Magnetics - this might make it easier to find some specs on
exactly what currents it takesto drive it etc.
Mike Williams
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Grant Saviers adds
I think you can add
- Ferroxcube (Saugerties, NY sp?) - OEM supplier of core & planes
- RCA - Waltham, MA or nearby & Taiwan - OEM & RCA supplier of cores and planes
- DEC - bought the RCA core making facility and Taiwan stringing. Only made for DEC
- IBM - only made for IBM
Henry Crouse bought DEC's core memories before he bought RCA. Next time I see him I ask for his list of suppliers.
Grant
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diagram from magnetic core patent