UNIVERSAL DIGITAL COMPUTER—A TEACHING MACHINE

A. V. TRIKHANOV

(Presented by the scientific seminar
of the Department of Computer Engineering)

The widespread introduction of digital computing technology into all branches of the national economy poses the serious task of the mass training of engineering personnel in the development, technical, and mathematical servicing of electronic digital computers.

The training of such personnel is carried out in specialty 0608 in the course on digital computers. In the course of instruction, students perform laboratory and practical exercises. The use of various equipment for conducting laboratory and, in part, practical classes is the subject of this article.

First of all, the question arises of practical classes on electronic digital computers. These classes are planned for two courses: the course on digital computers and the course “Programming and Algorithmic Languages.” In the first course, work on the machine may be organized both as practical and as laboratory work; in the second course, of course, as practical work.

As far as we know, students’ work on a machine usually has the character of a practical exercise—the machine is used as a computing instrument (input, debugging, solution).

At Tomsk Polytechnic Institute, the universal computer “Minsk-1” is used in the digital-computer course as laboratory equipment for carrying out work on its individual units and devices; that is, the classes have the character of laboratory work.

Thus, the question will be considered from the standpoint of laboratory classes.

In conducting laboratory classes in the course on digital computers, a variety of laboratory equipment is used, ranging from elementary circuits of logic elements up to serial electronic digital computers of various types and capacities. Widely known teaching installations of the UM type, developed and manufactured by the Special Design Bureau of Mathematical Machines of the Siberian Branch of the USSR Academy of Sciences, are used [4].

All this laboratory equipment, in accordance with the structure of a digital computer, is divided into groups [2]:

equipment for electronic-computer elements,
equipment for the main units,
equipment for specialized units,
equipment for devices,
teaching and universal electronic digital computers.

And for all these groups the departments have either purchased or independently developed and manufactured laboratory mock-ups [5].

At the Department of Computer Engineering of the Tomsk Polytechnic Institute there is some laboratory equipment for standard units (basic and specialized).

These are, first of all, the UM-1 and UM-6 installations of the Special Design Bureau of the Ministry of Higher Education of the USSR. At the department, mock-ups have been developed and manufactured of decoders, counters with various conversion factors and with both directions of counting, an accumulating adder with successive carries, a combinational adder, comparison circuits, serial- and parallel-action registers, and mock-ups for synthesizing standard units on “Ural-10” modules. They are made in the traditional spirit. The capabilities of individual mock-ups are comparatively small. Their cost is high. As such mock-ups become morally obsolete, they must be replaced by new ones and new descriptions must be written for them.

The design and structure of a laboratory mock-up for units can be developed as standard and universal. Such work was carried out at the Department of Computer Engineering of TPI.

The structural arrangement, besides being unified for all units, resembles the rack (cabinet) of a universal machine. Standard cells with the necessary elements (flip-flops, inverters, gates, amplifiers, signaling elements, coincidence circuits, OR circuits) or modules (micromodules) of some system are inserted into the sections of the rack.

The number and composition of the elements or modules (micromodules) is chosen on the basis of calculating a set of diverse units of a given bit capacity.

On the side of a small inclined control panel with the necessary control organs, signaling elements, a keyboard, and preventive-checking organs, the rack has a patch field. On this field the specified unit is wired. A replaceable patch field makes it possible to speed up and increase the reliability of conducting laboratory classes.

It is very easy to introduce specified faults into this mock-up. In addition to the possibility of synthesizing a unit, such a universal mock-up is cheaper to produce, simpler to manufacture and adjust, and, which is also very important, it makes it possible to organize the frontal method of conducting classes comparatively simply. And here the point is not only the indicated positive aspects of the mock-up, but also the fact that the period of its moral obsolescence is significantly longer than that of traditional (specialized) mock-ups.

In turn, the frontal method of conducting laboratory classes is very well coordinated with the principle of programmed control of readiness for laboratory classes.

Mock-ups for elements and standard units are important not only for training specialists in the field of digital computers, but also, undoubtedly, for training specialists who develop and introduce various means of digital computing technology; that is, they can have a certain independent significance. In part, laboratory equipment for devices (memory devices, arithmetic units, input-output, control devices) is in the same position.

However, this is expensive, complex equipment, developed and prepared on the basis of separate blocks of particular types of electronic digital computers, and, of course, it has a primary and perhaps principal purpose

for training in electronic digital computers. Not all departments of computer engineering have such devices, especially in full scope.

Attempts are made to compensate for their absence by holding classes on universal machines. But the latter, in general, are not specially intended for this. They serve to carry out a variety of calculations, and their use in this respect is the most expedient.

The use of an electronic digital computer as laboratory equipment for studying and investigating the operation of devices is methodologically inefficient (there is almost no possibility of modifying the structure, checking various variants, taking frequency characteristics, however strange this may be, observing and recording time diagrams of the operation of units, introducing faults).

But, of course, investigating the interaction of the machine’s devices with one another can be carried out only on it.

It is also economically disadvantageous to use an electronic digital computer as laboratory equipment for devices. When working with one device, the others are essentially idle. And in practice it is impossible, in this case, to organize a laboratory session on other devices. This, of course, would be possible on a machine with multiprogram control with time sharing [1].

In this case, one high-capacity computer can work with a large number (many dozens and even hundreds) of remote consoles and simultaneously serve many users.

In connection with the use of electronic digital computers for instruction, Academician V. M. Glushkov [1] also emphasizes the great role of low-capacity machines for acquiring initial experience in the use of modern computing technology, which is extremely important in the mass introduction of computers. Our industry produces such machines (Promin, NAIRI, MIR), which have won great popularity among users.

Thus, the use of general-purpose machines for training specialists both in operation and in programming causes certain technical difficulties and, moreover, is economically inexpedient. For this purpose it is desirable to have a special digital machine that would be convenient and reliable in operation, would have a simplified instruction system, and would make it possible to demonstrate visually all stages in the execution of any machine operation.

One variant of such a machine was developed and described in the book by V. I. Matov, O. A. Nikolaev, A. V. Fetisov, and N. S. Zhdanovich, An Educational Digital Computer, published by the State Power Engineering Publishing House in 1963 [3].

It is intended for the instruction and training of specialists in the operation of digital machines and in programming.

The educational machine has much in common with the universal machine “Ural-1.”

We have no other information on the development and use of educational electronic digital computers for training specialists in electronic digital computers.

On the other hand, the creation and use of simulators employing computer technology for the training of pilots, cosmonauts, tank crews, automobile drivers, etc., is widely known.

At the Department of Computer Engineering of TPI, the following equipment for devices is available: a UM-3 installation for studying the arithmetic operations of addition and multiplication in sequential form; a simplified multi-digit arithmetic unit of sequential action for the addition and subtraction of numbers; a model

four-bit type-Z control unit, a model for studying a type-Z magnetic MOSU system, operating in write–read mode.

On the universal model, multiplication and division devices using various algorithms have been designed and built. Switching inside the units is carried out on cells. On the patchboard only the connections between units are set up. Experience has shown that the universal model is also highly appropriate for organizing laboratory classes on electronic digital computer devices.

It should be noted that there is one more positive feature characteristic of the universal model described. Its use in the educational process helps students become practically acquainted with certain aspects of the design procedure, with the preparation of certain design documents (identification of cells; preparation of wiring and other diagrams of cells, panels, and cabinets; preparation of connection tables; issues of assembling, powering up, and debugging a prototype, etc.).

Conclusions

1. It is advisable that laboratory models for the computer course be developed as standard and universal models.

2. The Ministry of Higher and Secondary Specialized Education of the USSR should be requested to raise with the Ministry of Instrument Making, Automation Equipment, and Control Systems of the USSR the question of developing and producing a small electronic digital computer that takes into account the problems of training specialists in computers.

3. The supply of departments of computing machines with the latest laboratory equipment and the latest small electronic digital computers should be improved.

Literature

1. V. M. Glushkov. Prospects for the use of computer technology. In: Interorgtechnika-66, Optinpribor, 1967.

2. Laboratory Practicum for the Course “Discrete-Action Computing Machines.” Edited by N. A. Smirnov and V. B. Smolov. “Vysshaya shkola,” 1966.

3. V. I. Matov et al. Educational Digital Computing Machine, REI, Moscow–Leningrad, 1963.

4. Educational-Laboratory Equipment for Higher and Secondary Specialized Educational Institutions. Catalog of the Special Design Bureau of the Ministry of Higher and Secondary Specialized Education of the USSR. “Vysshaya shkola,” Moscow, 1967.

5. A. G. Shikin and G. K. Barabanova. Collection of Laboratory Exercises for the Course “Discrete-Action Computing Machines.” MEI, Moscow, 1964.