Parts of Soviet computer

I don't know much about computer which used these boards. I got them many years ago from Agricultural University and they probably got them from Jagiellonian University in Cracow. Modules are populated with TTL chips, Soviet equivalents of western 74xx series. These chips have been manufactured by many plants in USSR, some of them manufactured only small batches of chips in late 1970s (see "EC" and "lightbulb" logo). Most chips are from 1978 and 1979.
One of boards seems to be "patched" with wires, so the computer was serviced. Stamps on boards are typical quality control stamps, date from 1979 and OTK stamp (meaning that device complies to military specifications, but these specifications are very different in quality - It's Soviet Union, they used not the best hardware, but the most accessible one!).
Boards can be configured using soldered jumpers. All of them have rack latches on one side and edge connectors on the other.

In Agricultural University I've also seen modules with 2 edge connectors, located 90 degrees from each other (on 2 sides of square PCB).

Manufacturer ???

Origin Soviet Union
Year of unit late 1970s
Year of introduction ??
Type Parts of ?computer?



If you are curious or want to reverse-engineer something, here are high-resolution scans of these boards:

BE671M Component side Solder side
BE679M Component side Solder side
BE680M Component side Solder side
BE810-01M Component side Solder side