MESM (Ukrainian: MEOM, Мала Електронна Обчислювальна Машина; Russian: МЭСМ, Малая Электронно-Счетная Машина; 'Small Electronic Calculating Machine') 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 Kyiv). 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

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

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 additionally could use a magnetic drum that stored up to 5000 codes of numbers or commands. An electromechanical printer or photo device was used for output.