computer science

MESM

MESM is a computer science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand MESM rather than just read about it. In short: MESM was the first universally programmable electronic computer in the Soviet Union. By some authors, it was also depicted as the first one in continental Europe, even though the electromechanical computers Zuse Z4 and the Swedish BARK preceded it.

Key takeaways

MESM belongs to computer science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect MESM to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of MESM from memory before moving on to harder problems.

Reference excerpt

MESM was the first universally programmable electronic computer in the Soviet Union. By some authors, it was also depicted as the first one in continental Europe, even though the electromechanical computers Zuse Z4 and the Swedish BARK preceded it.

Overview MESM was created by a team of scientists under the direction of Sergei Alekseyevich Lebedev from the Kiev Institute of Electrotechnology in the Ukrainian SSR, at Feofaniya (near Kiev). Initially, MESM was conceived as a layout or model of a Large Electronic Calculating Machine and letter "M" in the title meant "model" (prototype). Work on the machine was research in nature, in order to experimentally test the principles of constructing universal digital computers. After the first successes and in order to meet the extensive governmental needs of computer technology, it was decided to complete the layout of a full-fledged machine capable of "solving real problems". MESM became operational in 1950. It had about 6,000 vacuum tubes and consumed 25 kW of power. It could perform approximately 3,000 operations per minute.

Creation and operation history

Principal computer architecture scheme was ready by the end of 1949. As well as a few schematic diagrams of an individual blocks. In 1950 the computer was mounted in a two-story building of the former hostel of a convent in Feofania, where a psychiatric hospital was located before the Second World War. November 6, 1950: team performed the first test launch. Test task was: f ( n ) = { Y ′ ′ + Y = 0 Y ( 0 ) = 0 Y ( π ) = 0 {\displaystyle f(n)={\begin{cases}Y\prime \prime +Y=0\\Y(0)=0\\Y(\pi )=0\end{cases}}}

January 4, 1951: First useful calculations performed. Calculate the factorial of a number, raise a number in a power. The computer was shown to a special commission of the USSR State Academy of Sciences. The team was led by Mstislav Keldysh. December 25, 1951: Official government testing passed successfully. USSR Academy of Sciences and Mstislav Keldysh began regular operation of the MESM. It was operated until 1957, and then transferred to Kyiv Polytechnic Institute for training purposes 1959: MESM dismantled. Boris Malinovsky recalled: “Computer was split into pieces, which were used to build series of stands, after all all of them was thrown away.” Many of the electron tubes and other components left from MESM are stored in the Foundation for the History and Development of Computer Science and Technology in the Kiev House of Scientists of the National Academy of Sciences of Ukraine.

System specification Arithmetic Logic Unit universal parallel action flip-flop based Number representation binary fixed points 16-n bits per number plus with one sign bit Instructions 20 binary bits per command The first 4 bits - operation code The next 5 bits - first operand address another 5 it the second operand address The last 6 bits - operation result address Following instruction types supported addition add with carry subtraction multiplication division binary shifts comparison taking into account mark absolute value comparison transfer of control magnetic drum read stop RAM Flip-flop based Data and code separated 31 machine words for data 63 machine words for code ROM 31 machine words for data 63 machine words for code Clock rate 5 kHz Performance About 3000 operations per minute (total time of one cycle is 17.6 ms; division operation takes from 17.6 to 20.8 ms) The computer was built using 6000 vacuum tubes, where about 3500 were triodes and 2500 were diodes. The system occupied 60 m2 (646 square feet) of space and used about 25 kW of power. Data was read from punched cards or typed using a plug switch. It could additionally use a magnetic drum that stored up to 5000 codes of numbers or commands. An electromechanical printer or photo device was used for output.

See also History of computing in the Soviet Union

Notes

References

Worked examples

Example 1 — a first encounter with MESM

Start with the simplest possible case. Write down what MESM claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In computer science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to MESM before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about MESM ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of MESM

In research: MESM appears in computer science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses MESM in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: MESM is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1950 in the Soviet Union, 1950s computers, Computer-related introductions in 1950, so understanding it makes those chapters shorter.
In everyday life: Look for MESM outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study MESM in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what MESM means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain MESM out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is MESM in simple terms?

Why does MESM matter?

Because it connects several computer science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study MESM?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on MESM.