The Line of Specialized Computers “Carat” for the USSR Naval Fleet | History of Computing in Ukraine

The Line of Specialized Computers “Carat” for the USSR Naval Fleet

In November 1976, by the decree of the Minister of Defense, the first of the USSR unified computers "Carat" was to be supplied to the Soviet Navy. The creation of a compact and reliable computer with reasonably high functional parameters radically changed the situation in marine instrumentation technology. It greatly simplified the process of creating modern computerized electronic systems in the Navy.


Ivan V. Kudryavtsev

Vilen N. Plotnikov

"Carat" was an "illegitimate child" one could say. The history of its creation began with the appointment of Vilen N. Plotnikov to the Kyiv Institute of Radio Electronics. In this new position he began independently researching the recently discovered elements in digital computer technology for transistors with potential links which had not yet been applied. In doing so, he had a lot of support from I.V.Kudryavtsev, the director of SPI.

In 1963 Plotnikov’s laboratory introduced, developed and completed flat micro modules (FMM) as basic units for new devices. For the first time in Ukraine and the former Soviet Union, a series-produced universal element was created, allowing the development of computers and other digital equipment to the highest technical level of the time.

FMM was assembled from micro-elements, mounted on both sides with the printed microplate (9x17 mm in size) with perpendicular pin terminals at a pitch of 4 mm. FMM was placed in a thin-walled aluminum case and filled with compound for protection against mechanical and climatic influences.  FMM 4N02 was 17.5x9, 5x6, 3 mm in size and it weighed up to 2 grams.

This wasn’t the end of the research. Plotnikov’s next goal was the creation of a computer which would  benefit the Navy. They needed reliable elements smaller than the FMM. At that time, the first, although still imperfect, IC chips of domestic production were created, followed shortly after by large-scale integrated circuits (LSI).  I.V. Kudryavtsev, the head of SRI,  supported Plotnikov’s initiative to start using these components to build a new computer at a higher technological level.  Plotnikov had to get approval to use the microchips in developing his systems from ministers in Moscow, which took a huge effort.

Thus began a new phase:  the creation of multi-chip integrated circuits, a completely new direction for computer component development. It was new not only in the country but also abroad (at least in Europe). Within a few years reports emerged that the US was using similar elements (multichips) for military purposes.

In the USSR the new multichips were called hybrid large integrated circuits (HLIC). They were named HLIC "Varduva” and later "Series 240".

Plotnikov’s laboratory created a document entitled "Basic characteristics of the computer ‘Carat’", where they also attached functional schemes and order codes.

During this time, in 1969, new difficulties arose. The Committee on Electronics of the USSR thought that the development and production of computer equipment for ship systems should be carried out in specialized institutes, design bureaus and plants. The committee did not like that computers were being developed by "the systems analysts", - organizations whose task it was to create very sophisticated ship electronic systems. On the one hand, it was fair that computer equipment should not be created by "amateurs" but by experts. On the other hand, this approach had disadvantages, because it separated computer technology developers from the requirements put forward by ship electronic system developers. The head of the SRI, Ivan Kudryavtsev, had the courage to disobey the High Committee and decided to create a home computer supported by Plotnikov.

This computer development was disguised under a different name, where instead of a ‘machine’ they called it a digital computing device (DCD). DCD was not advertised in the industry. This happened later, on the Ministry of Shipbuilding Industry's initiative of the four Leningrad instrument-making enterprises. They got information about the main characteristics of the computer "Carat", and its development was approved by competent organizations. In spite of the fact that the development of a unified computer did not meet the main profile of the SRI, Kudryavtsev decided to achieve the promotion of "Carat." However, by the end of 1970 "Carat’s" competitor was developed under the Ministry of Shipbuilding Industry.

The head enterprise of the Ministry of Shipbuilding Industry was CSRI "Agat", which developed a concept of computer systems unification for those developed in the industry. They proposed the creation of a line of software-compatible 32-bit machines of various capacities under the title “Ataka” ("Attack"). The concept was well-reasoned and persuasive.

At this time in Plotnikov’s laboratory they had already manufactured and configured the first sample of "Carat", which was a compact 24-bit machine based on HLIC "Varduva." The weight and dimensions of it were not worse than those proposed of similar kinds, and the performance of specific tasks was above average in comparison to similar models. However, "Carat" did not fit into the drafted concept. Soon the rivalry between the two computers surfaced. Some specialists from the Ministry of Shipbuilding Industry didn’t support the "Carat" computer.

In order to solve the conflict of interests, a special expert committee was created, with the task of defining the best computer for submarines. That committee had to decide which computers, from Moscow or Kyiv, would become the master copy for the shipbuilding industry. For several days, specialists from numerous Ministry enterprises considered the characteristics of the computers related to submarine relevant tasks.  It turned out that ‘Carat’ was the most suitable for solving the majority of tasks.

The atmosphere was tense but most experts supported the ‘Carat’ as the unified sample for this onboard computers series-production.

In two months, Plotnikov’s laboratory had to prepare the draft of the technical project and submit it for defense to the head organization, which was headed by a Rear Admiral I.A.Semko - a vigorous opponent of "Carat".

Over the next two months they completed the draft of the technical project for the computer and the debugging of an experimental prototype of the "Carat". On March 25, 1971, a meeting of the Scientific and Technical Council of the Ministry of Shipbuilding Industry  occured on the same issue. It took place with the invitation of representatives of interested companies and organizations (without vote), and the customers of electronic systems. As a result, it was decided to finalise the “Carat” project and move into production.

Further development and testing of two prototype computers took place in 1971-1972. As a result, the scientific and technical council accepted the Ministry’s recommendations to use the "Carat" in various information processing systems for management and control on the surface ships and submarines of the Navy.

The developed ‘Carat’ was waiting to take one more test, to "pass" the exam at the State commission. The State commission came to Kyiv and began its test on March 26th, 1973. For the next six months the committee members conducted more than 100 inspections and tests. The results and findings were reflected in the 128 protocols.

 In 1974, the successful completion of pilot tests led to an official recommendation: to produce and deliver samples of the computer to the Ministry of Defence. Two years later the Minister of Defense adopted the computer "Carat" for supply.

Creating a compact and reliable computer with reasonably high functional parameters radically changed the marine instrument  industry. From then on, the developers of any system could use a software method to solve problems when installing one or more machines. There were no problems with getting samples of computers with the required performance of the programming tasks and with the debugging of permanent memory, in line with the customers’ software. Computer failures were rare. For example, in navigation systems computer samples worked on the projects for 20 thousand hours without a single failure, which is several times higher than the requirements of specification.

The computer was used in more than 60 systems and complexes, which were developed by the enterprises of four ministries. In simple systems, the computer could be used with minimal modifications, and 15 or more "Carat" computers were installed on the largest modern ships, in its maximum version with multiple on-board systems.

In the early 80's the modernization of the unified computer was finished in order to improve performance of problem solving in sonar and other systems ("Carat-CM").

New constructs and components were used. Storage devices on large-scale integrated circuits completely replaced the magnetic tape storages. The modification of "Carat-CM-E" was developed based on sections of large microprocessor integrated circuits. The "Carat” modification increased the speed up to 2.5 million transactions per second in order to process information from the radar systems with phased array antennas. More sophisticated computer tools were used to develop and expand the cross-automation system of programming and debugging. The programmers could work on a personal computer that was connected to the main system in order to debug the programs for "Carat".

Besides the "Carat", Plotnikov’s laboratory developed a single-board computer based on the standard 16-bit microprocessors, which have been used in a number of systems for civil purposes. But in complex systems, they did not replace, but complemented the high-performance "Carat" computers.

The Institute of Radio Electronics developed 15 modifications of the computer "Carat" line, and prepared about 5 million software instructions. About two thousand of these computers were produced in USSR plants which were used in the 60 types of systems. So the Soviet ships were equipped with fail-safe computerized control systems which served in the Navy for decades. This was all due to the profound conviction of Ivan Kudryavtsev, Vilen Plotnikov and their colleagues in the rightness of their cause, and their persistent struggle for the launch of the "Carat".