The Electronika BK is a series of 16-bit PDP-11 compatible home computers developed under the Electronika brand by NPO Scientific Center, the leading microcomputer design team in the Soviet Union at the time. It is also the predecessor of the more powerful UKNC and DPRK micros.
First released in 1984 and with a К1801ВМ1 CPU at 3 MHz. The K1801BM1 is a Soviet LSI-11 compatible CPU, so basically a clone of the CPU used in DEC's PDP-11. The BK0010 was the only official (government-approved and accounted for in economic planning) Soviet home computer design in mass production.
They sold for about 600-650 rubles. This was expensive, but marginally affordable, as the average Soviet monthly wage was then about 150 rubles. Thus, they became one of the most popular home computer models in the Soviet Union. Later, in the 1990s, their powerful central processing unit (CPU) and straightforward, easy-to-program design made them popular as demoscene machines.
BK (БК) is a Russian abbreviation for "бытовой компьютер" - household (or home) computer.
The model we have is the second version. The first version had a very uncomfortable keyboard (pseudo-membrane), an archaic FOCAL programming language that came standard, and the lack of peripherals and software. The second version has a better keyboard and Vilnius BASIC p-code compiler in ROM (a miniaturized clone of MSX Basic).