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(acronym for Russian bystrodeistvuiushchaia elektronnaia schetnaia mashina, “high-speed electronic calculator”), the name of a series of digital computers developed at the Institute of Precise Mechanics and Computer Technology of the Academy of Sciences of the USSR. The BESM was one of the first modern general-purpose digital computers built with vacuum tubes and designed to solve scientific and engineering problems. One BESM was built and has been in operation since 1953.

The BESM has been improved: the electroacoustic mercury lines used as direct-access storage were replaced with cathode-ray tubes (1954) and then with ferrite cores (1956). In this form the machine is known as the BESM-1. (See Table 1 for main parameters of BESM computers.)

Thanks to modernization, the speed and operating reliability of the BESM (72 percent usable time with 8 percent downtime and 20 percent under maintenance) have increased. Various problems were solved on the BESM-1—for example, the orbits of 700 small planets of the solar system were calculated and cumbersome geodesic calculations were made. The design of the BESM-1 was revised for application to industrial technology, and in 1958 lot production of the tube-based BESM-2 was begun. It was already supplied with

Table 1. Main parameters of BESM digital computers
 BESM, 1953BESM-1, 1954BESM-2, 1958BESM-3M, 1964BESM-4, 1966BESM-6, 1967
Instruction format...............333331
Bit configuration...............393939454548
Performance time for operation (microseconds):
Direct-access storage:
Capacity (words)...............
Cycle (microseconds)...............40-6408-108-108-108-102
External magnetic drum storage:
Capacity (words)...............
2 × 5,1202 × 5,1202 × 5,1204 × 16,3844 × 16,38416 × 32,768
Speed of exchange (words per second)...............80080080012,00014,00050,000
Average waiting time (microseconds)...............4040402020
External magnetic tape storage:
Capacity (thousands of words)...............
4 × 304 × 304 × 304 × 9004 × 1,00032 × 1,000
Speed of exchange (words per second)...............4004004003,5003,5008,000
Basic elements (thousands of items):
Semiconductor diodes...............
Semiconductor triodes...............151540
Vacuum tubes...............455
Power consumed (kilovolt-amperes)...............7575757820
(without external devices)

a set of standard programs and with compiling and interpreting systems that made the programming process easier.

The BESM-3M and BESM-4 computers are semiconductor machines with a developed instruction repertoire (coinciding with that of the M-20 machine), a set of devices that ensure the solution of complex problems of mathematics, statistics, and accounting, and software for the programming process (set of subroutines, translators, and so on). The BESM-4, a modification of the BESM-3M, has a great capacity for solving economic planning problems.

The BESM-6, a semiconductor machine with an average operating speed of 1 million operations per second, a large memory capacity, and a developed system of input-output devices, was built for problems requiring a large number of computations. In its logic, diagram, and design execution, the BESM-6 reflects leading trends in the development of current computer technology and the automation of programming. The machine combines the work of individual units and exchange of information with external units. A multiprogram mode is envisioned which will increase the use efficiency of all units of the machine during the simultaneous solving of several problems. There is a hardware interrupt system, a “memory protection” circuit, and automatic address assignment. The control program, using these circuits, excludes the influence of some problems on others while they are being solved simultaneously, automatically distributes direct-access and external storage among the problems, and coordinates the work of external devices. A super high-speed memory, which is automatically controlled by a special circuit and which keeps the most frequently encountered statements in it, is a particular feature of the BESM-6. It is possible for operators at several control consoles equipped with alphanumeric printers to work simultaneously and independently, and they can be located at a distance and transmit information along communications channels.


Lebedev, S. A., and V. A. Mel’nikov. Obshchee opisanie BESM i metodika vypolneniia operatsii. Moscow, 1959.


References in periodicals archive ?
Before the BESM, DepEd conducted a two-week Post-Conflict Needs Assessment (PCNA) in the 39 schools last October to assess non-infrastructure components such as furniture, learning materials, computers, and other teaching equipment.
Of the 39 schools evaluated by the engineers, 14 have already been opened and these schools are included in the first round of BESM program.
To make the BESM more efficient, it utilizes a "Paired and Twinned System" that has three simultaneous parts including a Marawi City school paired with an ARMM Division Office; a Marawi City school having additional Mindanao region and division partners that will handle the manpower; and a Marawi City school that twinned regions and divisions in Luzon and Visayas that will provide the resources and materials
Offered a place at the MGU graduate school with Liapunov, he studied both theoretical and practical questions of automatic programming, the effort culminating in a working language and compiler system for the BESM computer; his 1956 report on the topic was published almost simultaneously as a monograph in Russian (1958) and English (1959).
Ershov disregarded Liapunov's recommendation to defend on the basis of his work on the BESM programming and recorded his doubts over the sincerity of Liapunov's evaluation of his work on the theory of programing: "Interesting, what does he really think about me and all this[?
Ershov, "Ob odnom metode obrashcheniia matrits," DokladyANSSSR 100, 2 (1955): 209-11; Ershov, Programmiruiushchaia programma dlia bystrodeistvuiushchei elektronnoi schetnoi mashiny (Moscow: Akademiia nauk SSSR, 1958), published in English as Programming Program for the BESM Computer (London: Pergamon, 1959).
Prior to the upcoming conduct of the BESM, DepEd conducted a two-week Post-Conflict Needs Assessment (PCNA) in the same 39 schools last October to assess non-infrastructure components such as furniture, learning materials, computers, and other teaching equipment.
Selon l'Institut Universitaire de la Recherche Scientifique, qui s'enorgueillit d'avoir pris en charge la publication du BESM et contribue ainsi a constituer une source remarquable pour l'etude de l'evolution sociale et economique du Maroc contemporain, le BESM represente [beaucoup moins que] le fleuron [beaucoup plus grand que] de ses publications.
Et c'est en souvenir de tous ceux qui ont contribue a faire du BESM l'un des meilleurs periodiques universitaires marocain, que l'equipe de l'IURS en reprend en 2007 la publication.
Pour le quatre-vingtieme anniversaire du BESM, l'IURS publie un numero special, le nA169, en hommage a tous ceux qui ont contribue a faire de cette publication une revue de qualite.

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