BESM (БЭСМ) stands for "Большая Электронно-Счётная Машина" (Bolshaja Elektronno-Schetnaja Mashina) in Russian, which can be translated as "Large Electronic-Computing Machine" or simply "Large Computer".

Several types of BESM have been built.

BESM-1 was built in 1953 using approximately 5,000 vacuum tubes. Only one such machine has been built. At the time of completion, it was the fastest computer in Europe. The floating point numbers were represented as 39-bit words: 32 bits for the numeric part, 1 bit for sign, 1 + 5 bits for the exponent. It was capable of representing numbers in the range 10^-9 — 10¹⁰. BESM-1 had 1024 words read-write RAM based on ferritic cores, and 1024 words of read-only memory based on semiconducting diodes. It also had external storage: 4 magnetic tape units of 30,000 words each, and fast magnetic drum storage with capacity of 5120 words with access rate of 800 words/second. The computer was capable of performing 8—10 KFlops per second. The energy consumption was approximately 30 kW, not accounting for the cooling systems.

BESM-2 also used vacuum tubes

BESM-3M and BESM-4 were built using transistors. Their architecture was similar to that of the M-20 and M-220 series. Word size was 45 bits. (30 BESM-4 machines have been built.)

BESM-6 was a completely new supercomputer system. It was designed in Institute of Precision Mechanics and Computer Engineering in 1965, production started in 1967. This is a mainframe type computer. BESM-6 was made up of discrete components, i.e. it did not use integrated circuits. Word size was 48 bits, address size 15 bits, addressable memory 192 K bytes (32 K words), working frequency 10 MHz, nominal performance 1 MFlops per second. BESM-6 was widely used in USSR in 1970s for various number-crunching tasks. 355 such machines have been built. Production ended in 1987.

BESM-6 was the first Soviet computer that was provided with an operating system and a Fortran compiler.

The later development of BESM-6 was Elbrus.

See also

• Sergei Alekseyevich Lebedev
• List of Soviet computer systems

External link

• BESM-6 Nostalgia Page