Setun () was a computer developed in 1958 at
Moscow State University
Moscow State University (MSU), officially M. V. Lomonosov Moscow State University,. is a public university, public research university in Moscow, Russia. The university includes 15 research institutes, 43 faculties, more than 300 departments, a ...
. It was built under the leadership of
Sergei Sobolev
Prof Sergei Lvovich Sobolev, FRSE (; 6 October 1908 – 3 January 1989) was a Soviet Union, Soviet mathematician working in mathematical analysis and partial differential equations.
Sobolev introduced notions that are now fundamental for severa ...
and
Nikolay Brusentsov. It was the first modern
ternary computer
A ternary computer, also called trinary computer, is one that uses ternary logic (i.e., base 3) instead of the more common binary system (i.e., base 2) in its calculations. Ternary computers use trits, instead of binary bits.
Types of states ...
, using the
balanced ternary
Balanced ternary is a ternary numeral system (i.e. base 3 with three Numerical digit, digits) that uses a balanced signed-digit representation of the integers in which the digits have the values −1, 0, and 1. This stands in contrast to the stand ...
numeral system and three-valued
ternary logic
In logic, a three-valued logic (also trinary logic, trivalent, ternary, or trilean, sometimes abbreviated 3VL) is any of several many-valued logic systems in which there are three truth values indicating ''true'', ''false'', and some third value ...
instead of the two-valued
binary
Binary may refer to:
Science and technology Mathematics
* Binary number, a representation of numbers using only two values (0 and 1) for each digit
* Binary function, a function that takes two arguments
* Binary operation, a mathematical op ...
logic prevalent in other computers.
Overview
The computer was built to fulfill the needs of Moscow State University. It was manufactured at the
Kazan
Kazan; , IPA: Help:IPA/Tatar, ɑzanis the largest city and capital city, capital of Tatarstan, Russia. The city lies at the confluence of the Volga and the Kazanka (river), Kazanka Rivers, covering an area of , with a population of over 1. ...
Mathematical plant. Fifty computers were built from 1959 until 1965, when production was halted. The characteristic operating memory consisted of 81 words of memory, each word composed of 18
trits (ternary digits) with additional 1944 words on
magnetic drum
Drum memory was a magnetic data storage device invented by Gustav Tauschek in 1932 in Austria. Drums were widely used in the 1950s and into the 1960s as computer memory.
Many early computers, called drum computers or drum machines, used dru ...
(total of about 7 KB). Between 1965 and 1970, a regular binary computer was used at Moscow State University to replace it. Although this replacement binary computer performed equally well, it was 2.5 times the cost of the Setun.
In 1970, a new ternary computer architecture, the
Setun-70, was developed.
Edsger W. Dijkstra
Edsger Wybe Dijkstra ( ; ; 11 May 1930 – 6 August 2002) was a Dutch computer scientist, programmer, software engineer, mathematician, and science essayist.
Born in Rotterdam in the Netherlands, Dijkstra studied mathematics and physics and the ...
's ideas of
structured programming Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making specific disciplined use of the structured control flow constructs of selection ( if/then/else) and repet ...
were implemented in the hardware of this computer. The short instructions set was developed and implemented by
Nikolay Brusentsov independently from
RISC architecture principles.
The Setun-70 hardware architecture was transformed into the Dialogue System of Structured Programming (DSSP). DSSP emulates the "Setun 70" architecture on binary computers, thus it fulfills the advantages of structured programming. DSSP programming language has similar syntax to the
Forth programming language but has a different sequence of base instructions, especially conditional jump instructions. DSSP was developed by Nikolay Brusentsov and doctoral students in the 1980s at
Moscow State University
Moscow State University (MSU), officially M. V. Lomonosov Moscow State University,. is a public university, public research university in Moscow, Russia. The university includes 15 research institutes, 43 faculties, more than 300 departments, a ...
. A 32-bit version was implemented in 1989.
History
Initiation of the project
The Setun project was initiated by
Sergei Sobolev
Prof Sergei Lvovich Sobolev, FRSE (; 6 October 1908 – 3 January 1989) was a Soviet Union, Soviet mathematician working in mathematical analysis and partial differential equations.
Sobolev introduced notions that are now fundamental for severa ...
, in order to develop a small computer for use at the
Moscow State University
Moscow State University (MSU), officially M. V. Lomonosov Moscow State University,. is a public university, public research university in Moscow, Russia. The university includes 15 research institutes, 43 faculties, more than 300 departments, a ...
, after the planned transfer of the M-2 computer to the university got canceled in 1953. In 1956, He organized a series of seminars analyzing the disadvantages of existing computers and various plans for technical implementation. These meetings include participants from the Moscow State University, the Institute of Atomic Energe, and other institutes of the Academy of Sciences. Notable attendees include Shura-Bura, Konstantin Adolfovich Semendaev, and Zhogolev. On one of these seminars on April 23, 1956,
Nikolay Petrovich Brusentsov was appointed as the executive designer and supervisor of the project.
At the time, Brusentsov was a graduate (equivalent to a master degree, See
Education in Russia
In Russia, the state provides most education services regulating education through the Ministry of Education and the Ministry of Science and Higher Education. Regional authorities regulate education within their jurisdictions within the prev ...
, Traditional model) at Moscow State University, who was graduated from the
Moscow Energy Institute. Before appointing Brusentsov as the executive designer of Setun computer, Sobolev transferred Brusentsov to the Mechanics-Mathematics department and sent him to Gutenmakher's laboratory at the Institute for Precision Mechanics to gain relevant experience. To Brusentsov, this is an invaluable experience. In the lab, he had access to the lab's computers and their supporting documentations, which Brusentsov found being "technically weak". Brusentsov then decided to use a ternary number system.
Setun computer
Sobolev continued to support the project both by finding assistants and participating in the discussion. In 1956, Brusentsov started the design with four engineers and five technicians plus himself. The whole team worked in a 60-square-meter room with laboratory tables, where they designed and assembled the machine by hand. Zhogolev worked as the main programmer, and together with him, Brusentsov developed the computer architecture of Setun. In 1958, the team grew to 20 people, and the first model of the Setun computer was assembled. The name Setun comes from a river near the University.
After the first model of Setun was built, the
Kazan Mathematical Machines Factory was decreed by the Soviet Cabinet of Ministers to mass-produce the Setun computers. However, the leadership at the Kazan plant was not interested in large-scale computer production. The second model built in the factory was sent back because the plant managers and officials maintained that the computer was not yet reliable. The team was forced to manually adjust the second model. On November 30, 1961, the director of the Kazan factory was forced to sign an act which ended the attempts to cease the production of the Setun computer. The computers were then produced at the rate of 15-20 machines annually until 1965, when the plant refused to continue the production as the sold price of the computer was too low.
While Setun attracted significant interest from abroad, the Ministry of Foreign Trade never filled the orders received. Only 50 Setun computers are manufractured, 30 of which was used in the higher education institutions inside the Soviet Union.
Setun-70 computer
Between 1961 and 1968, Brusentsov and Zhogolev developed Setun-70, the next generation of Setun computer with a new architecture. It was designed for effective software development, in which the ternary system played a key role. Both addresses and operations are in syllables, where each syllable's length equals to 6 trits (about 9.5 bits). Algebraic expressions of operands by syllables replace the instructions as words in the traditional design, as the instruction set is updated to allow more variance of operand length.
The algebra is supplemented by testing, control, and input-output operations. The user can add operations on their own without reducing the computer's performance, thus providing the ideal conditions for structured programming. Brusentsov claimed that the programming time on Setun-70 is reduced by five to tenfold with unprecedented reliability, clarity, compactness and speed.
The functioning algorithm of Setun-70 was comprehensively described in expanded
Algol-60.
End of the Setun project
The new university rector considered Brusentsov's research and computer design a
pseudo-science
Pseudoscience consists of statements, beliefs, or practices that claim to be both scientific and factual but are incompatible with the scientific method. Pseudoscience is often characterized by contradictory, exaggerated or unfalsifiable cl ...
. After the Setun-70 project, Brusentsov's lab was relocated from the Computer Center at Moscow State University to an attic in a student dormitory, and the original prototype of the Setun computer was destroyed. The Setun-70 model was took to the new attic laboratory and was used as a basis for developing the educational computer system Master Work Station.
Adoption and application
Thanks to the simplicity and naturalness of its architecture, as well as a well-designed programming system that included the following interpreters—IP-2 (floating-point, 8 decimal digits), IP-3 (floating-point, 6 decimal digits), IP-4 (complex numbers, 8 decimal digits), IP-5 (floating-point, 12 decimal digits)—plus the POLIZ autocode with its operating system and standard subroutine library (floating-point, 6 decimal digits), the Setun computers were quickly mastered by users in universities, industrial plants, and research institutes. They proved to be an effective tool for solving practically important problems across a wide range of fields, from scientific modeling and engineering calculations to weather forecasting and enterprise management optimization.
At user seminars on the Setun computers—held at Moscow State University (1965), the Lyudinovo Diesel-Locomotive Plant (1968), and Irkutsk Polytechnic Institute (1969)—dozens of reports were presented on successful real-world applications for the national economy. Owing to its balanced ternary code, Setun turned out to be a truly universal, easily programmable, and highly efficient computing instrument. It earned a strong reputation, notably as an educational tool for teaching computational mathematics in more than thirty universities. At the Zhukovsky Air Force Engineering Academy, Setun even became the platform for the first automated computer-based learning system.
Critics
Brian Hayes argues in his article ''Third Base'' that Brusentsov did not realize the theoretical advantage of the base 3 system:
Ternary compared to binary
Balanced ternary systems and ternary computers are not unprecedented in history. Thomas Fowler built a mechanical computer in 1840 using balanced ternary system.
The balanced ternary representation of numbers and its related arithmetics was applied in number theory back to
Leonhard Euler
Leonhard Euler ( ; ; ; 15 April 170718 September 1783) was a Swiss polymath who was active as a mathematician, physicist, astronomer, logician, geographer, and engineer. He founded the studies of graph theory and topology and made influential ...
and was briefly discussed by
Claude Shannon
Claude Elwood Shannon (April 30, 1916 – February 24, 2001) was an American mathematician, electrical engineer, computer scientist, cryptographer and inventor known as the "father of information theory" and the man who laid the foundations of th ...
in his paper ''a symmetric notation of numbers'' published in 1950.
Despite the ternary design never become massively produced, there have been discussions on the advantages of the ternary system over the binary system, and great interest was present on the ternary and more generally on the multi-valued logic systems in the academy.
Advantages
Brusentsov found the ternary number system superior over the binary number system: it allowed him to create very simple and reliable elements, plus he needed seven times fewer elements than the Gutenmakher's computers. The power source requirements were also signficantly reduced because a smaller amount of magnetic rods and diodes was used. He also found the natural number-coding system used in the ternary system superior over the direct, reciprocal and supplementary number coding used in the binary system. He maintains that the ternary system is superior to binary in most aspects, published several papers advocating the ternary system during 1985-2014.
The symmetic nature of balanced ternary logic allows for natural representation of negative numbers.
The ternary system is also more efficient from an
information theory
Information theory is the mathematical study of the quantification (science), quantification, Data storage, storage, and telecommunications, communication of information. The field was established and formalized by Claude Shannon in the 1940s, ...
persepctive.
Donald Knuth
Donald Ervin Knuth ( ; born January 10, 1938) is an American computer scientist and mathematician. He is a professor emeritus at Stanford University. He is the 1974 recipient of the ACM Turing Award, informally considered the Nobel Prize of comp ...
wrote in his book ''The art of Computer Programming'' that "Perhaps the symmetric properties and simple arithmetic of this number system will prove to be quite important some day,"
noting that,In the paper ''The Prospects for Multivalued Logic: A Technology and Applications View'',
Kenneth C. Smith argued that multi-valued logic is a solution to the interconnection problem in digital systems. In particular,
Douglas W.Jones suggests that the ternary system will reduce the number of interconnection wires by
.
Disadvantages
Douglas W.Jones made a series of computations and designs algorithms of ternary system on his homepage under the name ''the Trenary Manifesto'', including fast ternary addition, multiplication, and division. It turns out that much of the improved efficiency in the interconnection and digit representation is balanced out by requiring more gates in the computations. For example, the ternary addition, while achieving the same computational speed as binary addition, requires
more logic.
Meanwhile, many have suggested that ternary circuits are hard to develop, especially when most modern digital flows are binary.
In the paper ''Comparison of Binary and Multivalued ICs According to VLSI Criteria'' written by Daniel Etiemble & Michel Israël, the authors compared binary and multivalued integrated circuits by examining their performance in detail, and discovered that while the design of multivalued circuits are valid and useful, they have not surpassed the binary circuits. They wrote in the conclusion that
See also
*
History of computing in the Soviet Union
References
{{List of Soviet computer systems
Early computers
Soviet computer systems
Soviet inventions