English Version

Aleksandridi Tamara
(), alexandridi@mail.ru

Computer M-2

To develop computer M-2, a special creative group was formed. Scientific advisor of the group was Isaac Brook, correspondent member of Academy of Science of the USSR. Head of the group was M. Kartsev.

The working team, developing M-2, included from 7 up to 10 engineers it depended upon a stage of development. The arithmetic unit was developed by M. Kartsev, V. Belynsky, and A. Zalkind, electrostatic memory device was developed by T. Alexandrididi and Yu. Lavrenyuk, control device was developed by L. Legezo, V. Knyazev, and G. Tanetov, magnetic memory device was developed by A. Sthurov and L. Legezo, input and output devices were developed by A. Zalkind, power supply system was developed by V. Belynsky, Yu. Lavrenyuk, and V. Knyazev, control panel was developed by V. Belynsky and A. Sthurov.

Designers, mechanics, and technicians I. Gelgaft, A. Grechushkin, N. Nemtsev, F. Pzheutsky, I. Shvilpe, D. Yermochenkov, L. Fedorov, G. Korostylev and others made a great contribution to the construction work.

Computer M-2 was developed and constructed as a unique one at the laboratory of electrical systems of the Energy Institute of AS USSR named after G. Krzhizhanovsky under the decree of the Presidium of Academy of Science of the USSR.

The computer included the following devices: arithmetic unit, programming gauge (control device), inner memory device, input and output devices, and outer memory device.

Development and installation was carried out in a very brief time from April up to December of the year 1952. In January of 1953 computer M-2 with memory on a magnet drum was put to operation. In June of 1953 electrostatic memory device based on electron-emitting tubes 13-LO-37 was installed.

In the winter of 1954-55 the computer was renovated. To develop the computer ferrite operative memory device with working capacity of 4096 words was worked out, designed and installed in the computer. It demanded the introduction of a special register to memorize the area of the memory currently being used and also of special operation of changing of the register content (shifting the memory areas). The pioneer idea of shortened addresses in commands and shortened operation codes as means of concordance of command and format numbers was used in the computer M-2 for the first time.

General view of computer M-2

Computer M-2 main parameters.

Number system - binary.

Number presentation with a floating point and with a fixed point.

Number of binary discharges - 34.

Instruction code system three addresses.

Operations:addition, subtraction, multiplication, division, module matching, algebra matching, logical multiplication, etc. (all in all 30 operations).

Speed - 2000-3000 op/sec.

Inner MD:

- magnet drum - 512 34-binary digit numbers,

- electrostatic -512 34- binary digit numbers,

- ferrite - 4096 34-binary digit numbers.

Outer MD magnetic tape for 50 thousand numbers.

Data input with the help of transmitter from perforated paper tape at 30 numbers per minute speed.

Data output in the chart form, printed by roll teletype. Printing speed was 24 numbers per minute.

The Computer M-2 Block-Scheme

Arithmetic unit (AU) is designed to operate with numbers: addition, subtraction, multiplication, division and a few logical operations.

There are three main registers in AU, designated by the letters A, B, C and one additional register, designated by the letter E.

When we do addition and subtraction, the numbers are being placed into B and C registers, and the result is summarized in B register. When we do multiplication, the numbers are placed in A and C register, and the result is summarized in B register. When division is being done, divisible is being placed in B register, divisor is being placed in C register, and the result is summarized in B register.

All the numbers are being received from memory devices into the A register and then are being transferred into the other AU registers. The record of the result of the operation is also done from the A register. Thus, the A register serves as a link between inner MD and AU. The same register serves for the connection inner memory devices with outer memory device, and with input and output devices.

Every register consists of 33 triggers, numerated from 1 up to 33.

Depending on the system (with a floating point or with a fixed one), the register operation of AU is being organized differently. If the operation is being made at a fixed point, all the registers work as a whole unit, and every register trigger corresponds to the definite digit number. In this case, register trigger #1 presents top binary digit number.

If operations with floating point are being done, then the registers are divided into two sections: exponent is being established in the triggers from #1 up to 6, and mantissa is being established in triggers from #7 up to 33. In this case, trigger #1 defines digit sign, and trigger #3 presents top mantissa digit.

Arithmetic unit is totally of a parallel type: number reception from memory devices, transmission from one register to the other, and summation are being done simultaneously in all digits.

Memory devices.There were two inner memory devices in the computer M-2 magnetic device and electrostatic one. Both devices are of a parallel type recording and reading could be performed simultaneously on all digits.

Magnetic device. Every number which is to be memorized is represented as a tiny magnet of either directions and it is resulted from a section of a rotating drum being magnetized. A drum is a duralumin cylinder with ferrite-magnet cover. There are 512 recorded signals on a circumference of a drum. They represent values of one digit of all numbers. Thus, 512 numbers can be storedin a magnet memory device simultaneously. Every element that holds a number is provided with its own address (from #0 up to 511).

Electrostatic device. In a electrostatic memory device every binary number to be memorized is presented as an electric charge, placed on a definite section of an electric screen of an electron-emitting tube. The number of tubes is equal to the number of digits (34). The values of a digit of all memorized numbers are being stored on the tube screen. All in all there are 512 cells with independent charges. Thus, 512 numbers or instructions could be stored simultaneously in the electrostatic memory device. Every cell on a screen has its own address. For the MD in question the addresses from #512 up to 1023. To choose the appropriate cell on a screen the place of an electron had to be changed. Electrostatic MD was the fastest of all known in 1952.

Outer memory device based on a magnet tape is build as a conventional tape recorder MAG-8. The operation mode of an outer MD is different from the operation mode of an inner MD, namely: it cant be used for operative work of the arithmetic unit

To further develop the computer M-2, ferrite memory device was designed, produced and installed in the computer. It was working on the principle of current correspondence with the volume 4096 34-digit numbers. The head of the group working on the device was M. Kartsev.The members of the group were young graduates: O. Rosnitsky, E. Filinov, L. Ivanov, Y. Glukhov, R. Shidlovsky. The installation of the ferrite memory increased the computer parameters to a higher level

Programming counter was designed for automatic operation control. The programming gauge selects instructions coded as numbers in a proper order out of the inner MD, deciphers also transfers numbers from one MD to the other and stops operations at the end of calculations. To control the computer the programming gauge might perform semiautomatic (pace) operation. them, chooses the right numbers according to the instructions, operates with them and records the results of operations in the proper cells of the inner MD. When it is predetermined by the program, the programming gauge puts the resulted data out on a printer or on a magnet tape, replenishes the content of inner memory devices through input devices or from the magnet tape. It

Input and output devices.

Input devices are designed for primarily filling of inner memory device by numbers and instructions and for replenishing the content of the memory devices in the process of operation. There are two input devices installed in the computer: photoelectric and electromechanical. Both photoelectric and electromechanical input devices read information from the perforated paper tape. Telegraph paper tape for 5 paths is being used; the sixth one is a leading path. Five path combination related to one number is being read either by mechanical device, placed in the input device or by the beam of light in the photoelectric input device. Then it is being transferred to the input five-trigger register. The speed of various devices differs from each other: electromechanical device operates at the speed one number per 2 seconds, while photoelectrical device operates at the speed one number per 0,03 seconds.In computer there is also additional type boarding device, with the help of which one is able to put in the computer any number or instruction.

Output device is designed for printing the complete results of calculations. Roll telegraph teletype is used for this purpose. Output data are being printed in the form of spreads in 8-symbol numbers in decimal or sixteenth systems; they might be put on a perforated paper tape simultaneously. Printing speed is one number per 2,5 seconds.

Computer parts.

The main electronic schemes of the computer M-2 (triggers, valves, amplifiers, etc.) were built on radio tubes, logic schemes were built on transistors (small sized cupric rectifiers KVMP-2-7). Radio tubes 6N8C, 6ZH4B, 6P9 were used. All in all there were 1879 electronic tubes in the computer.


The main units and blocks were installed in the four cabinets: arithmetic unit was placed in cabinet #1, programming gauge in cabinet #2, electronic part of magnet MD and input-output devices in cabinet #3, electrostatic MD (later ferrite MD) in cabinet #4. All the cabinets were installed on one podium. Cabinet #5 (power supply) was installed into the podium.

Control panel and two tables were aligned to the podium: to the right of the panel there was teletype desk, and to the left input and tape recorder desk.

The entire electronic part of the computer was assembled on demountable subblocks. Every computer unit consisted of 6 blocks. Blocks were installed on a chassis, aligned to the cabinet frame. The plugs were placed on the block chassis. They were used to perform electric junction of demountable sublocks with the installation of a given unit. .

Subblock construction in the computer

Computer operation.

Computer M-2 began operation on a regular basis in the summer of 1953. Special instructions were printed for users. It included instructions on input-output, service programs, programs of elementary functions, etc. A special group of consultans was organized. The Head of the group was A. Brudno, PhD, full professor. The programmers workshop also was conducted on a regular basis. Sunday time was allocated for programmers who worked on theoretical development of intellectual, recognition, and game soft wares. Mathematical apparatus of the computer was being developed as well. In particular, A. Brudno offered and put into practice method of content symbols (predecessors of AUTOCODE, ASSEMBLER).

A lot of research institutes used this computer to work on their theoretical and applied problems, to wit: Institute of Atomic Energy, Institute of Theoretical and Experimental Physics, Moscow Aircraft Institute, Institute of Gas and Oil, named after Gubkin, Moscow State University solve, and others

In the year of 1956 the first experiment of remote computer control was carried out.

Computer M-2 has been in operation more than 15 years.


"High Speed Computer M-2. Uner edition of the Correspondent Member of AS USSR Isaac Brook. State publishing house of technical-theoretical literature. Moscow, 1957

"Arithmetic Units in Computers. M. Kartsev, Moscow, 1958

Users references.

great three-address computer M-2 was built at the institute. It was built by a gifted engineer M. Kartsev. He invented very convenient command system. It has something in common with a poem there should be only one author. Probably because of that the command system appeared to be so convenient a real poem in codes.

Today the computer M-2 would have looked very big by size and very small by operation possibilities just 512 cells of electronic memory and 512 cells of drum memory. But for the year 1954 this computer was excellent: it possessed the floating point, and the speed reached 2000 operations per second.

. Kronrod. Discussion on Programming. M. Editronal URSS, 2001.

Working with nearly the same speed as the Strela computer, computer M-2 consisted 4 times less of electronic tubes, used 7-8 times less of power supply, was more compact (just 22 square meters) and cost approximately 10 times less. This accomplishment was achieved by the use of conventional oscillograph electron-emitting tubes for MD and by the use of semi conducted diodes in logical schemes

Ye. Filinov.The History of Computer Science in Russia (the former USSR). Proceedings of International conference-exhibition Open Sysytems is the Way to a New World. April 17-20, 1995, Moscow