# Electronic Digital Computer URAL-2 (Урал-2)

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Ivan Vasilyevich Urnev

- Chief designer –
**B.I. Rameev**(*Rameev Bashir Iskanderovich*). - Leading assistant designers: A.N. Nevskiy, V.I. Mukhin, A.I. Pavlov, A.G. Kalmykov, G.S. Smirnov, A.S. Gorshkov, L.N. Bogoslovskiy, M.N. Knyazev, O.F. Lobov.
- Organisation in charge of the project and design: Penza Scientific Research Institute of Controlling Computers.
- Producing plant: Penza Plant of Computing Analytic Machines (under the USSR Ministry of Instrumentation and Automation Means \MIAM\).

- Completion of the design (year): 1959.
- Beginning of the serial production (year): 1959.
- Finishing the serial production (year): 1964.
- Application field: solving of broad range of mathematic problems at computing centres, scientific research institutes, design bureaus and industrial enterprises.
- Number of produced computers: 139 pieces.

## Description

(computer structure, architecture and peripheral devices)

URAL-2 – computer with one-address binary arithmetic and a fixed point. Word length – 40 bit (one number or two statements). Computer had parallel structure. Ferrite core RAM.

URAL-2 consisted of the following units:

- Key input device;
- Control and reading device;
- Perforator for input data;
- Output data perforator;
- Printer;
- Punched tape memory storage;
- Magnetic tape memory storage;
- Magnetic drum memory storage;
- Ferrite core memory;
- Arithmetic device;
- Operation control unit;
- Power supply unit.

## Components

Electron-valve circuits (mainly 6Н8 valves), diode-resistor gates.

### Design and configuration

It basically repeated URAL-1. Upper parts of the rack cabinets in the computer main section were filled with valve cells, lower parts – with power supply blocks.

## Computer manufacturing technologies

Traditional technologies of mechanical processing, processing of synthetic materials and assembly. Principle novelties were introduced into technology of the ferrite core storage and peripheral devices.

## Software

Testing programs and control tasks.

## Basic technical and operational data

- Number of digits for mantissa of decimal numbers at input and output/printing — 8 decimal digits;
- Number of significant digits in octal numbers at input and output/printing - 14 octal digits;
- Range of a number changing:

- with floating point – 2^{-39}≤ |x|≤2^{39}-1;

- with fixed point - 2^{-19}≤ |x|≤2^{19}-1; - Computation arithmetic for numbers at input and output/printing – decimal and octal ones;
- Computation system for statements at input and output/printing – octal;
- Computation system for statements and numbers in the computer – binary;
- number of bits in the computer number – 40 (1-sign of a number, 32-mantissa of the number, 1-sign of exponent, 6-exponent);
- Operation with both 40-bit sells and 20-bit cells;
- Number representation – operation with both floating and fixed point;
- Instruction system – single address;
- Number of basic instructions – 41;
- Main units operation principle – parallel with variable cycle length;
- System of control – operating control with supported by test-programs and preventive control by changing of circuitry operation mode;
- Average performance – 5000-6000 ops;
- Ferrite storage capacity – 2043 40-bit numbers or 4096 instructions;
- Magnetic drum storage 8192 40-bit numbers per a drum. Parallel usage of up to 8 drums was possible;
- Average number input/output speed (from/to magnetic drum) – 3000 (±10%) numbers/sec (including the first cell location time));
- Magnetic tape storage capacity – 100 000 40-bit binary numbers;
- Reading (and input) of numbers from magnetic tape (without zone location time) – 2000 (±10%) numbers/seс;
- Perforated tape storage capacity – 10000 40-bit binary numbers;
- Reading (and input) of numbers from punched tape (without zone location time) – 150 (±10%) numbers/seс;
- Number of outputs for bringing computation results (to printer, perforator (puncher) recording and other devices) – 2
- Printer performance – 20 (±10%) lines/sec;
- Output numbers perforating (punching) speed – 160 (±10%) numbers/min.

Electric supply – three phase alternating current net with 380/220V and frequency 50 Hz. Stable operation within the voltage changing range from 195V to 240V. Stability of voltage is maintained by three-phase stabiliser with magnetic control of 30 kWA. Required premises (within one room) 90-100 sq m.

## Specific features of the computer

Ferrite core memory provided increasing of performance. Magnetic drum storage also expanded possibilities of the computer efficient implementation in scientific and engineering computations.

Translated by A. Nitussov