CER-12

CER-12 (Central processor unit) 1971.

CER (Serbian: Цифарски Електронски Рачунар – Digital Electronic Computer) model 12 was an third generation digital computer developed by Mihajlo Pupin Institute (Serbia) in 1971 and intended for "business and statistical data processing"(see ref.Lit.#1 and #4). However, manufacturer also stated, at the time, that having in mind its architecture and performance, it can also be used successfully in solving "wide array of scientific and technical issues" (ref.Lit.#2 and #3). Computer CER-12 consisted of multiple modules connected via wire wrap and connectors.

Central Unit

Primary memory

• Type: magnetic core memory
• Capacity: up to 8 modules, each consisting of 8 kilowords (1 word = 4 8-bit bytes).
• Speed: cycle time: 1 μs, access time 0.4 μs.

Arithmetic unit contains:

• 32-bit accumulator register
• two separate groups of eight 2-byte index registers
• single-byte adder supporting both binary and BCD addition (same unit is used for subtraction, multiplication and division had to be implemented in software)

Control Unit Control unit contains a program counter and instruction registers. It fetches instructions and facilitates program flow. It supports single-operand instruction set and works with all 16 index registers of the arithmetic unit.

Interrupt System Interrupt system of CER-12 consists of a number of dedicated registers and software. It supports up to 32 interrupt channels.

Control Panel Control panel of CER-12 allowed the operator to control and alter program flow and/or to eliminate errors detected detected by error-detection circuitry. It features a number of indicators and switches.

Operating system and other software

Following software was shipped with CER-12:

• Operating System
• "Symbolic programming language" and assembler (called "autocoder")
• Input/output subroutines
• A number of test programs
• COBOL and FORTRAN IV compilers
• Linear programming and PERT planning software
• A library of applications and subroutines

Peripherals

• 5-8 track, 500 characters per second punched tape reader PE 1001
• 5-8 track, 150 characters per second tape puncher PE 1501
• CDC 9432 magnetic disk drive as secondary storage (4,096,000 characters per 6-disk, 10-surface volume organized into 100 cylinders with sixteen 1536-bit (48 processor words) sectors; track-to-track seek: 30 ms; rotational latecy: 25 ms)
• IBM 1735 teleprinter
• ICL 667 line printer (725 lines per minute for 64-character set or 880 lines per minute for 50-character set)

Literature

1. Vladislav Paunovic: Arithmetic unit of the CER-12 computer, AUTOMATIKA, No 3, pp. 161–165, Zagreb 1971.
2. Veselin Potic, Mihael Savikin, I/O system of the CER-12 computer, AUTOMATIKA,No 3, pp. 166–176, Zagreb 1971.
3. V Batanovic, J.Kon (Ed): IMP Riznica znanja, pp. 5–8, M.Pupin Institute and PKS, Belgrade 2006. (in Serbian)
4. Dusan Hristovic: Razvoj Racunarstva Srbije (History of Computing in Serbia), PHLOGISTON journal, No 18, Museum MNT-SANU, Belgrade 2010/2011.

See also

• CER Computers
• Mihajlo Pupin Institute
• History of computer hardware in the SFRY