Page 11 - Kotov

BESM-6 was designed at the Institute of Precision Mechanics and Computer Engineering in Moscow. This was
the main computer in research centers and in large data centers, the most influential among the domestic computer
designs, very popular among Russian programmers. The production started in 1968 in Moscow. The basic config-
uration included 192 Kbyte of core memory (a virtual memory system allowed to expand this up to 768K bytes),
magnetic drums, proprietary magnetic tape drives, teletypes, typewriters, alphanumeric printers, and punchcard/
punchtape IOs. About 350 machines have been produced until early 80’s.
The computer speed was one mln instructions per second, the memory cycle was 2 msec with 0.8 msec access
time, the parallel interface for the six channels of external memory and 32 communication channels. Other im-
portant features:

BESM-6

• Deep overlapping execution of instructions based on an asynchronous pipeline architecture.
• High-speed associative buffer memory.
• The first virtual memory in the Russian computers.
• Operating system with a multiprogram mode.

High performance was achieved with relatively small number of semiconductors (approximately 60,000 transis-
tors and 180,000 diodes).
BESM-6 was a “number cruncher”, so it had no any specific instructions for symbolic processing. The memory
could be addressed only a word by word. BESM-6 had one of the largest and most active user community in
the Soviet computing. There were compilers for the most popular programming languages: Algol-60, Fortran,
Pascal, APL, Lisp, Refal, Forth, C , and others. However, inadequate operating system and small programming
space forced to use mostly low-level programming languages. This hampered the development of unsophisticated
software and applications in the Soviet Union.
An extension of BESM-6 (named AS-6), which was better suited for symbolic processing, has been designed, but
only several (4 or 5) systems have been actually built.

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