Nikolay P. Brusentsov | History of Computing in Ukraine

Nikolay P. Brusentsov

Nikolay Petrovich Brusentsov was the creator of the world's only ternary computer, “Setun”, the first model of which he and his colleagues assembled by hand.

This future scientist was born on February 7, 1925 in Kamenskoye (now Dniprodzerzhinsk). In February 1943 he was drafted into the army and sent to Sverdlovsk to be trained as a radio operator. Six months later, Brusentsov was assigned to the 154th Infantry Division, where he became a radio operator in the exploration department of the 2nd Battalion of the 571st Artillery Regiment. In one of the battles, a shell exploded next to him, killing two of his comrades and an officer; Brusentsov was not injured. His combat services were rewarded with the Medal of Honor and the Order of the Red Star.

After his discharge, Brusentsov returned to Dniprodzerzhinsk. He graduated from the school for young workers in Kalinin (now Tver) with honors, and in 1948 joined the Radio Engineering Faculty of the Moscow Power Engineering Institute, where he studied along with M. A. Kartsev, a future renowned scientist in the computer field. For his diploma project, senior student Brusentsov created the tables of diffraction on an elliptical cylinder, which today are known as Brusentsov’s tables.

After his graduation in 1953, Nikolay Brusentsov was directed to work in the Special Design Bureau (SDB) at Moscow University, and following that, in the aboratory, which developed computers to use in educational institutions. Here, fate brought him to a brilliant mathematician, Sergei Sobolev, who was enthusiastic about  creating a small computer that would be suitable for college laboratories in cost, size and reliability. For this purpose a special laboratory was opened at the Computing Center of Moscow State University, which started a workshop for the first university programmers (Shura-Bura, Semendyaev, Zhogolev, and of course, Sobolev). Here they discussed the shortcomings of existing machines, considered the system commands and structure (of what is now called architecture), and the innovations and technical implementation options, and they were inclined to use magnetic elements, since transistors did not exist yet. The use of (at that time) conventional electronic tubes was ruled out, because the tube machines appeared cumbersome and power consuming. It was therefore decided to focus on ferrite cores and diodes, which were readily available.

At the workshop meeting on April 23, 1956, the participants made a final decision on the development of a small digital computer using magnetic logic elements (so far, with binary representation of data), and formulated technical requirements. They appointed Brusentsov as a development manager and the only executor.

By this time, a machine made ​​entirely on the pulsed diode magnetic elements already existed in the Institute of Precise Mechanics and Computer Science, in Gutenmakher’s laboratory. But Gutenmakher’s machine was of low performance and reliability, required a powerful source of sync pulses, and had many shortcomings.

Since it was decided to use magnetic elements for the new universal machine, Brusentsov, through the patronage of Sobolev, was admitted to Gutenmakher’s secret laboratory for an internship. Reflections on how to resolve the machine’s multiple problems unexpectedly led him to think about using the ternary notation, as it so happened that magnetic elements were very convenient for the construction of ternary digital devices. The ternary system made ​​it possible to create very simple and reliable elements on magnetic amplifiers, working in a pulsed mode. Brusnetsov developed and assembled a ternary adder circuit, which immediately performed secure work.

In 1958 Brusentsov’s laboratory staff (by this time there were nearly 20 people) made the first sample of the machine with their own hands. On the tenth day of the setup process the machine started working. It was called “Setun”, for the name of a river not far from Moscow University. Its simplicity and practicality was due to the display of numbers and commands in a symmetric code (- 1, 0, 1).  In fact, the university designers received the first RISC-computer. The length of the Setun’s machine word was 9 trits, a total of 24 commands. A special feature of the new machine was a paging and two-level memory organization. The magnetic drum, similar to an Ural computer drum, was associated with fast main memory by the paged transfer. This contributed to increased productivity, resulting in 4500 operations per second.

The State Commission that approved the “Setun” computer recognized the machine as the first operating sample of a universal computing machine working on the tubeless elements, characterized by high efficiency, sufficient reliability, small size and ease of maintenance. Soon it was decided to mass-produce “Setun” at the Kazan factory of Mathematical Machines, which eventually produced 50 Setun’ computers; 30 of them were placed in the higher educational institutions of the USSR.  “Setun”  was used to solve problems of mathematical modeling in physics and chemistry, production management optimization, short-term weather forecasting, engineering calculations, computer training, data processing, etc.

From 1961-1968, Brusentsov, along with Zhogolev, developed a more perfect machine, later called the Setun-70. It had non-traditional, two-stack architecture to provide favorable conditions for further development of its capacities by means of the interpreting systems method. The operating sample was tested in April 1970. Unfortunately, after the Setun-70’s design completion, assembly and setup, Brusentsov’s laboratory, by the decision of the university, was forced to stop its work. The only existing sample of the Setun-70 was used in the computer training system "Mentor."

Presently Nikolay Brusentsov heads the computer laboratory of the Faculty of Computational Mathematics and Cybernetics at Mikhail Lomonosov Moscow State University. The main emphases of his scientific activity are the architecture of digital computers, automated learning systems, and programming systems for mini- and microcomputers. Brusentsov supervises the research projects associated with the creation of microcomputer training and programming systems. He has published over 100 scientific papers, including the following studies: "Small digital computer Setun" (1965), “Minicomputers" (1979), "Microcomputers" (1985), and the textbook, "Basic Fortran" (1982). He also has 11 inventor's certificates. The book about the Setun’ computer was translated and published in German.

Nikolay Brusentsov is sure that "full computer science cannot limit itself to the universally-accepted (for technical reasons) binary system; the base should be ternary. I present convincing evidence for the correctness of this discovered way."