Plessey Memories Inc

Mus.Cat. NEWUC:2003.24.1 Mnfctr: Plessey Memories Inc Date: 1973 Part. No: 48-001-73 Serial No: 539
Comp: Mother Board Width: 364 mm Depth: 232 mm Height: 13 mm Weight: 618 g

Front view

This is the front view of the storage module containing the addressing and drive circuitry.
The 26 silver components are large transisters.

This is the rear view. Underneath is the mother board,
on the top is the rear of the daughter board.

Removing the daughter board reveals the printed circuitry on the rear of the mother board.

Mus.Cat. NEWUC:2003.24.2 Mnfctr: Plessey Memories Inc Date: 1973 Part. No: 700016-103G Serial No: 1681
Comp: Daughter Board Width: 254 mm Depth: 203 mm Height: 19 mm Weight: 268 g

Turning the daughter board over reveals the core plane.
It is 16 pairs of core mats, 4 rows of 4 pairs. That is 32 core mats.
Each mat is 64 x 64 cores, totalling 4096 cores. So the total is 32 x 4096 = 131072,
divided by 8 to convert to bytes gives 16,384bytes, divided by 1024 gives 16Kbytes.


Going in closer shows the two wires threading the cores horizontally and vertically,
and the wire loom carrying a wire that threaded just one pair of core mats.
So this is 3 wire core storage. What are those four white flecks?

Zooming in closer to one of them shows that it is a join of two wires!

The actual size of the storage in this photograph is about 33mm,
so each pair of rows of rows of cores is 1mm.

The third wire loom and this join indicate that human hands were involved in making this core storage.
It beggers belief as to how.

Back to Core Storage