BESM
"BESM" - family of digital computers of general purpose oriented to solution
of the complex tasks of science and engineering. It is developed in Institute of
exact mechanics and computer facilities the USSS academy of Sience.
The work over the first machine was completed in 1952. In
this three-address parallel machine on electronic lamps (4000 lamps) the binary notation
with a floating point is used. By the structure, construction and characteristics the
machine took the level of the best foreign machines, "BESM" operated with
39-digit words with average speed of 10 thousand operations per second. At the
beginning the operating STORAGE on electronic - audio lines of delay replaced in the
further device by electron tube handsets, and then - by ferrite cores with the capacity of
1024 words with random sample was used in it. The external STORAGE - on two magnetic drums
up to 5120 words (speed of reading from a drum - 800 numbers per second) and
magnetic tape (120 thousand numbers). As devices of input a punched tape was used, for the
output then used a- magnetic tape with the consequent printing on the specially developed
high-speed phototyping device used for output of large scale arrays of data. Besides there
was an electromechanical printing station for printing check values and results in case of
their small amount in comparison with the volume of calculations (the speed of operation -
20 numbers per 1 second).
Interesting features of the structure of the machine were
introduction of local control of operations surpassing by the time fthe limitss of a
standard cycle, and also independet control at transition to subroutines. The machine
contained the long-term storage device for the subroutines, which part was changeable. For
control there were applied both series of the tests, and specially developed methods of
logical control.
For 1959-1966 4 models of this family were created:
"BESM - 2", "BESM - 3", "BESM - ÇÌ" and "BESM -
4". The inprovement concerned the increase and modernizing of peripherals, transition
to semiconducting element base, increase of capacity of the RAM on magnetic cores, and
besides the capacity of the external STORAGES.
In 1967 the most powerful computer of the
given family - "BESM - 6" (its speed was about 1 million operations per second)
was created (look at the figure). The application in
the machine of one-address command system confirms the common tendency of increase
flexibility of command control. Characteristic features of the internal arrangement of the
central part of the machine are particulary the following: a high degree of local
parallelism, presence of the superfast storage device buffer, extended system of
operations, possibility of organization of stack memory and splitting of the main memory
on independent blocks. The machine made a wide usage of combination of operations of
accessl to the operating STORAGE with the operation of the arithmetic device and control
unit; in the machine there are five levels of preview of commands. The structure of the
machinepresupposes the applicationof time sharing and multiprogramming. This is provided
by the hardware system of interruption, circuit(scheme) of memory protection indicesing,
and advanced system of conversion of virtual mathematical addresses and physical address
of the main memory in dynamics of the score. The possibility is provided to use any part
of the memory as the storage device stack. In the machine thereare provided both indirect
addressing and wide possibilities of readdressing. 
In the CPU of the
machine there are 16 high-speed registers working with the speed 300 nanoseconds. Its
technical characteristics are the folloving: the length of a word - 50 bits (2 for
checking conjugation); the notation - binary; the with of representation of numbers - from
a floating point; the execution time of operations: additions - 1,2 microseconds,
multiplying - 2,1 microseconds; the command system - one-address; the length of the
command - 24 binary bits (2 for a word); the amount of main commands - 50 plus extracodes;
It is possible to expand the capacity of the RAM on cores - 32 thousand words (8 blocks),
up to 128 thousand words; the time of access to the RAM - 2 microseconds; the number of
lines of interruption - 40; the time of sample from memory - 0,8 microseconds; clock
frequency -10 megohertz. The electronic part of the machine includes 120 thousands of
diodes and 40 thousands of transistors. The external STORAGES: 16 drums with the capacity
of till 32 thousand words and 32 tape drive mechanisms with the capacity of a spool
on each mechanism of 1 million words.
The set of devices of the system of input-output
contains: the device of reading from punched cards - 700 cards per minute; the device of
reading from punched tapes - 1000 signs per second; a high-speed alphanumeric printing
station for 96 sumbols - 400 lines per minute (128 sumbols for aline); output card punches
- 100 cards per minute; tape punches - 20 signs per second, 4 keyboard punches; 1
verifier for punched cards and 2 tape punches. "BESM - 6" has advanced
mathematical support, the structure of with includes: the operating system of control of
line processing of the tasks and the programming system of the symbolic machine-oriented
languages and of the languages of a high level - FORTRAN, ALGOL and LISP. The
structure of the software includes besides packages of standard programs for FORTRAN
and ALGOL including a wide range of the engineering, scientific and technical tasks. The
total amount of software reaches several hundreds thousands of commands. The operating
system (OS) organizes multiprogram processing of several tasks, each of which has a
full capacity of the virtual storage provided in the machine. OS arranges physical
resources of memory a mong the tasks, using it page by page organization, provides
simultaneous, combined with with the operation centeral, processor, operation of the
external STORAGES and devices of input-output; organizes calling into operation of
necessary translators and compilers, access to standard programs and watches correctness
of execution of working programs, finding errors originating from the process of
execution. The programming system on the autocode allows in a symbolic way to write
programs taking into account all structural features of the machine, andthere by presents
the means of obtaining the most effective programs. The programming systems based on
the languages of high level (ALGOL and FORTRAN), represent possibilities to
formulate the lasts in the convenient and common mathematical form. The language LISP
gives wite possibilities for the creation of complex logical relational programs.
Those who are interested in the unique national machine BESM-6 we recommend Page of nostalgia of BESM-6.
Literature: Lebedev S.A., Melnikov V.A. General
description computer and technique of execution of operations. Ì., 1959; Machine
computing digital BESM-6. In the book: Products of a radioindustry. A directory, ò. 4.
Computer facilities. The release: electronic digital computers of general purpose. Ì.,
1968; Grubov V.I., Kirdan V.S.. Electronic computers and analog computers. Ê., 1969
[bibliogr. page 179-181].