Minsk-23 computer

n.a.

Beloiannisz Telecommunication Factory (BHG)

Structure

Central unit

Character-organized machine: 8 bpch

• control unit:
  • logic circuits built from individual semiconductors (mainly П16А transistors)
  • clock frequency: 250 kHz
• main store:
  • 40 kch (20 kW) ferrite ring RAM (2*16 blocks, each with 100*100 ferrite rings)
  • cycle time 13 μs
• fixed spreadsheets instead of calculators
• instead of channels, 8 data transmission interfaces to which control units (“switches”) can be connected

Periphery

• backup storage: 8 magnetic tape (½”) units (НМЛ-67); recording density 4 ch/mm
• external devices:
  • control typewriter (CONSUL-254)
  • punched card reader (УВВК-600), speed 600 cdpm
  • punch card punch (ПМЭ-80), speed 100 cdpm
  • punched tape reader (FS-1500), maximum speed 1500 chps
  • punched tape punch (ПЛ-80/8, maximum speed 80 chps
  • line printer (АЦПУ-128-2М), speed 380-420 lpm

Operation

The length of the instructions varies, but they always consist of an even number of characters – at least 4. Their structure:

• operation code (2 characters)
• title (4 characters)
• specifier (2 characters);

but they can be unaddressed, or have 1, 2, 3, or more addresses. (An example of the latter is the "clear flag bits in characters" instruction, which can have any number of addresses.) Special commands are used for searching and editing.

Character structure:

• 6 data bits, including 2 flag bits and a BCD character
• 2 check bits.

The first interface switch is built-in, while the others can be connected externally. Up to 8 external units can be connected to each switch, so the machine can handle up to 64 different peripheral devices simultaneously. Since the central unit controls the data transfer, the operation is interrupted during this process.

Decimal addition and subtraction of factors is done using calculation tables built into the protected area of the stock library. The exception is decimal-to-binary conversions.

Average operation speed 6 kips.

Program set

• magnetic tape operating system
• compilers: Autocode

The programs used in practice were developed by users, according to their own goals.

Historical curiosities

Most of the circuit boards are interchangeable with those of the Minsk-22.

The instruction set brings the autocode language as close as possible to machine code, thus allowing for economical use of the main memory capacity and efficient development of various data structures and information processing systems.

Resources

General description: BHG Orion TRT Technical Bulletins, XVIII. vol. 1. no. 1972

Detailed description: Minsk 23 description

Detailed technical description: Minsk 23 (Russian)