Ferrite core memory cassette

Computer RAM cassette. Similar cassettes were used in the "Nairi" and "M-20" computers. This cassette is probably from the M-220 computer (or its upgrades), since the computer capacity (47 bits) is very close to the number of cores in a number of cassettes (48 cores). The last bit is apparently the control one. The cassette is quite large - 24 cm wide, 38 cm long. The frame is made of PCB, the corners are reinforced with metal brackets. On both sides it was closed with protective covers. On the back side there are two guide pins for rack mounting, and on the front side there are two handles for attaching to the rack. One handle is engraved with the number 14, possibly the serial number of the cassette in the rack. There are no connectors for connection, the connection was made through soldered leads.

Internal structure and specifications

The inner space of the cassette consists of two sections. One has a memory part, and the other has a large number of wires and ferrite chokes. The memory part of the cassette contains two layers of ferrite rings, each layer is one continuous field of 66 by 48 rings each (3168 rings per word, 6336 rings in total). Type of memory organization is 2D type, when using two rings per bit. With this arrangement, the memory capacity of the cassette is 396 bytes.

Additional information

Produced by Kazan Computing Machine Plant.

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