M-20 - Soviet tube electronic computer . It was developed at the Institute of Precision Mechanics and Computer Engineering (ITMiVT) and SKB-245 under the guidance of S. A. Lebedev . Deputy chief designers are M.K. Sulim and M.R. Shura-Bura , the main developers are P.P. Golovistikov, V. Ya. Alekseev, V.V. Bardizh, V.N. Laut, A.A. Sokolov , M.V. Tyapkin, A.S. Fedorov. Development was started in 1955 and completed in 1958 . The computer was produced from 1959 to 1964 at the Kazan Plant of Mathematical Machines and the Moscow Plant of SAM , in total 63 sets were produced in Kazan  .
- Element base: 1600 vacuum tubes , semiconductor diodes
- Clock frequency: 666.7 kHz (one pulse in about 1.5 μs)
- Number representation system: binary floating point, 45 bits for number codes
- RAM: 4096 45-bit words on ferrite cores
- Buffer memory: three magnetic drums of 4096 words each
- External memory: magnetic tapes (4 blocks), punch cards
- Output device: printing device
- Productivity: on average, 20 thousand operations per second
- Occupied area: 170-200 sq.m.
- Power consumption: 50 kW, not including the cooling system
In non-academic sources  , one can find the statement that at the time of development, the M-20 was the fastest computer in the world. Apparently, this opinion is based on the book of B. N. Malinovsky  , according to which "it was successfully adopted by the State Commission with an assessment of" the fastest in the world "." This statement, however, is not true: the speed of the M-20 was 20 thousand operations per second, while, for example, the IBM 704 , manufactured since 1954 (that is, 5 years earlier), had a speed of 40 thousand operations per second, and presented on December 30, 1958 and supplied since 1959, the IBM 7090 transistor computer - more than 220 thousand operations per second   . Most likely, Soviet specialists at that time did not have enough information about the technical characteristics of American equipment.
Later, BESM-3M , BESM-4 , M-220 , M-220M , M-222 semiconductor machines were developed to replace the M-20 (the last two are in the SKB of the Kazan Computer Plant), software compatible with the M-20 and having a larger volume memory. Machines M-220M and M-222 received significant distribution in the military-industrial complex, they were produced until 1974 , in total more than 800 pieces were produced.
Sergey Vakulenko wrote the m20 emulator.
Dmitry Stefankov wrote a complete emulator of the M-20 digital computer .
Note. On this page you can also see detailed information on the digital computer M-20.
- M.R. Shura-Bura, V.S. Shtarkman. Computing machine M-20. Instructions for mathematical operation . - Moscow, 1962. Archived copy of January 22, 2016 on the Wayback Machine
- V.F. Lyashenko. Programming for computers with a command system type M-20. - Moscow: "Soviet Radio", 1974.
- P.P. Golovistikov. Machine M-20 . History ITMiVT . ITMiVT website. Date of treatment August 5, 2009. Archived March 11, 2012.
- General-purpose electronic computing machine M-20 . History of domestic computer technology. Universal computers. Family of computers M-20 . Virtual computer museum. Date of treatment August 6, 2009.
- Natalia Dubova. Translators from Algola-60 (Russian) // Computerworld Russia. - 1999. - No. 45 dated 05/12/1999 .