KDF9 Buffer Storage

Mus.Cat. NEWUC:2002.14 Mnfctr: English Electric Co. Ltd. Date: 1963 Ser. No: 0993 Model:
Comp: Buffer Storage Width: 207 mm Depth: 160 mm Height: 39 mm Weight: 750 g

KDF9 Buffer Storage

This is the buffer module. It contains one core mat of 24 x 16 cores.


This is a close up of the core mat.
There is only two wires that thread each core.
One threads each core 4 times, the other 8 times.
There is no third wire, as it is a simple storage of 16 x 24bit words.
To read a word a current would be sent down one of the wires
to set every core to zero.
Where the cores were changed the magnetic field would change
so induce a current in the other wire threading that core.
Where the core was not changed no such current would be induced.

So all the cores on that wire read would be changed one way.
It was a destructive readout.
A write cycle would automatically follow
where a half current to store a bit would be on every core that stored a "1",
and not to where there was a "0",
plus a half one current to the other wire.

Rear close-up

This is a close-up of of the rear
where it is easy to count the number of times each wire threads the core.

We have no idea why it is 4 and 8 windings through each core.
And would be delighted to hear from others as to why it was wired this way.

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