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Electronic Digital Computer Ural-4 (Урал-4)

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  1. Chief designer – B.I. Rameev (Rameev Bashir Iskanderovich).
    Leading assistant designers: A.N. Nevsky, V.I. Mukhin, A.G. Kalmykov, V.I. Smirnov, G.S. Gorshkov, L.N. Bogoslovsky, M.N. Knyasev, O.F. Lobov, etc.
  1. Basic organisation in charge of the computer project and design: Penza Scientific-Research Institute of Electronic Computing Machines.
  2. Producing plant: Penza Plant of Computing Analytic Machines (under MIAM).
  3. Completion of the design (year): 1961.
  4. Beginning of the serial production (year): 1962.
  5. Finishing the serial production (year): 1964.
  6. Application field: computations for expanded field of mathematic problems and industrial planning tasks at computation centres of scientific research institutes and industrial enterprises.
  7. Number of produced computers: 30 pieces.

(computer structure, architecture and peripheral devices)

Final variant of computer URAL-4 design was developed by numerous modifications of the basic URAL-2 model, which were conducted by two principal directions:

  1. Expanded set and increased number of additional input-output devices. Punched tape devices were replaced with punched card ones, numerical printer replaced with alphanumeric one with lines of 128 places.
  2. Increased capacity of external memory storages and their reliability. New memory devices with magnetic tape essentially enlarged volume of stored data. Record doubling and recording/keeping of control sums on the tape noticeably increased information storing reliability. Increased density of recording on magnetic drum doubled its capacity. Its speed also increased.

Number of URAL-4 instructions rose up to 51 through integrating of URAL-2 instructions. 8 magnetic drums and up to 12 magnetic tape cabinets could be simultaneously connected to the computer.


Electron-valve circuits with diode gates were the same as in URAL-1 and URAL-2.


Configuration of URAL-4 in general repeated URAL-2. Electron-valve cells were placed in the upper parts of the computer cabinets in its main part; power supply blocks were placed in the lower parts of the same cabinets. However, the punched-card devices, magnetic tape devices and alphanumeric printer had new design.

Assembly technologies

Traditional technologies of mechanical and plastic parts processing, same as in URAL-1, -2, were implemented. Technologies of the ferrite memory and peripheral devices manufacturing were new.


Test programs, control tasks.

Basic operational and technical data

URAL-4 was fully compatible with URAL-2 on software level, URAL-4 required 250 sq m, power consumption – 60 kWA.

Specific features of the computer

Increased number of additional peripheral devices essentially expanded URAL-4 possibilities at economic and planning information processing. Intermediate modification (between URAL-2 and URAL-4), which differed from them mainly with its specific set of peripheral devices, was put into commercial production as computer URAL-3.

Translated by A. Nitussov

Started by Eduard Proydakov in 1997
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