ES-5551M microcode memory unit

Microinstruction memory unit from the device for managing drives on magnetic disks and drums. The EC-5551M Removable Disk Manager is designed to manage up to eight EC-5056 drives with removable disk packs. The disk package consisted of 6 disks on one spindle, with a total capacity of 7.25 MB. The device could be connected to EC-1020 computers and others, providing compatibility in terms of transmission format and minimum data reading speed. It is a massive block consisting of two parts - storage and decryption. On the front side of the memory part there is a vertical handle for mounting / dismounting the unit to / from the rack. The handle is removable, underneath there are ferrite cores, code wires and readout windings. Attached to the lower side of the memory part is the part responsible for decoding the address, consisting of a case, inside which are enclosed arrays of diodes, and outside the guide for the distribution of code wires. On the back is a connector plug that connects the unit to the control unit. The nameplate says 5551M E006.

Internal structure and specifications

The memory part consists of 48 U-shaped ferrite cores, distributed in two groups of 24 pieces. Each group is individually stitched with code wires - address buses. 256 wires come from the decryption system. This way you can store 6144 bytes of data per group or 12,228 bytes per block.

Additional information

Developed by Penza Scientific Research Institute of Computer Engineering. Maked in 1974 году

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