ZAM-2

• Added index register and full list of commands
• Mercury memory replaced by magnetostrictive
• Magnetic drum memory doubled
• Instead of a call center, closed cabinets are used.
• In the Gamma version, replacing the matrix relay relay in magnetic drums with transistor elements

Number system and code words

• Family: ZAM
• System Controlled Unicast Dynamic Serial Computer
• Binary calculus system, record form - direct code ^[2]
  • 18-bit integers
  • 36-bit fractional numbers
  • 18-bit control word containing fields:
    • 1 bit: command modifier (operand length change)
    • 5 bit: order code
    • 12 bit: address
  • 32 arithmetic, logical and managerial teams with a length of 18 bits each; no floating point operations commands (list in the description of the SAS macro assembler)
• Speed: 1000 operations of addition / sec., 300 operations of multiplication / sec.

Memory

• On-line magnetostrictive memory on delay lines
  • 512 36-bit words
  • Average access time: 0.4 ms
• Permanent memory on magnetic drums
  • About 600 thousand bits (128 buses of 128 36-bit words)
  • Average access time: 40 ms (for relay heads), 20 ms (for transistor heads)

Internal Devices

• Teletype , speed 7 characters / sec.
• Photoelectric five-channel tape reader, 300 characters / sec.
• Five-channel tape recorder, 30 characters / sec.
• Card punch reader ELLIOTT-B 42 (in the version for GDR replaced by a card reproducer) ^[3]

Registers

• Arithmometer Registers
  • 36-bit register on magnetostrictive delay lines
    • Battery : 36 bits plus extra bit
    • Multiplier: 36 bits
  • Intermediate register
  • Single Bit Registers
    • Extra battery bit
    • Battery Sign Bit
    • Sign bit of the multiplier
• Control system registers
  • Instruction counter
  • Team roster
  • Repeat Counter for Multiply, Divide, and Shift Commands
  • Command Modification Bit

Technology

• About 400 electronic tubes and germanium point diodes
• Drum Transistors
• Packages installed on textolite tiles; spatial installation and soldered connections between the terminals
• Two cabinet sizes 2300 × 2000 × 400 mm (arithmetic meter, internal memory and control unit)
  • Operator table
  • Drum magnetic memory
  • Power supply
• Power supply: 3 phases 380/220 V, 50 Hz 12.5 kW
• Cooling: fans in cabinets and other equipment; controlled thermostat in the cabinet for internal memory to maintain a constant temperature; the computer itself does not need air conditioning

• SAS - macro assembler
• SAKO - high level language (autocode), "Polish FORTRAN"

• "Alpha": two copies, 1960-1961. The mercury memory, after completion of work on the specimens, was replaced by magnetostrictive. Used in an officer communications school in Zegrze and the Gliwice Chemicals Project Office.
• "Beta": two copies, 1961-1962. Magnetostrictive memory.
• "Gamma": eight copies, 1962-1965. Two copies transferred to the GDR. Magnetic drum memory uses transistors.

Annual computer use at the ETOPROJEKT computing center: ^[4]

• Longest trouble-free operation: 140 hours
• The longest accident time: 30 h
• The most common problems: I / O devices, but easily fixed.
• The most serious errors: RAM errors
• Reliability improved due to air conditioning

• Konrad Fiałkowski "Maszyna cyfrowa ZAM-2" Wydawnictwa Naukowo-Techniczne , Warszawa 1963 r.