CDC 3000 computer family

Control Data Corporation ( CDC, one of the "Big 9" computer companies in the US) released two major computer series in the 1960s: the "upper" (U) series (3600-3800) consisted of 48-bit machines, and the "lower" (L) series (3200-3500) consisted of 24-bit machines, but from 1967 both were surpassed by the world's first supercomputers ( 6xxx ).

The picture shows a 3800 console.

Category:

Medium machine

Technology:

Custom semiconductor

Origin:

import

Manufacturer:

Control Data Corporation, USA

Use

Operating time:

Issue: U: 1963-1965; L: 1964-1967

Typical applications:

Mainly technical and scientific calculations

Structure

Central unit

Word-organized machine: 24 bpW

control system: 24-bit instructions, four 15-bit index registers
main memory: two/three 32 KW ferrite ring RAM memory blocks
calculator: two (A, Q) 24-bit factor registers

Periphery

(CDC code numbers in parentheses)

backups:
- magnetic tapes (601, 604, 607)
- magnetic disks (808), 32-36 disks per spindle (∅ 32″), 10-disk interchangeable packs
external devices:
- punch card reader (405) (80 columns)
- punch card punch (415) (80 columns)
- line printers (136 chpl)
  - forgóhengeres (501, 505)
  - string (601)
- optical scanners (700, 915)

Operation

Instruction structure:

operation code: 6 bits
indirect address marker: 1 bit
index register address: 2 bits
main memory address: 15 bits

In the U-series machines, one machine word contained two instructions, so downward compatibility was available.

Operation speed: ~ 1 Mips (in 1965!)

1's complement number representation (-0 and +0 are different).

In long operations (multiplication, division) AQ was linked into a 48-bit E register.

Character set:

Printer code 6 bpch, no lowercase letters
Screen code: 63 / 64 characters, 'CDC graphic' and 'ASCII graphic' versions in both sets, can be changed per page (in time-sharing systems the wider versions were usually used)

Program set

General programs

operating system:
- L: RTS OS majd MSOS (Mass Storage OS)
- U: Master Master (interrupt handling, multi-user system, extended main memory management)
- L, U: SCOPE (real-time system)
programming languages:
- Compass (assembler)
- ANSI Fortran, MS Fortran
- ANSI Cobol, MS Cobol
- Snobol (text processing)
- Algol 60
- U: APL

Custom programs

n.a.

Historical curiosities

The last member of the series, the CDC 3500, released in 1967, was already built from integrated circuits and could be optionally supplemented with floating-point and decimal, as well as BDP (Business + Data Processing) operation instructions for performing business and commercial calculations.

Resources

Detailed historical and technical description: CDC 3000.

Created: 2016.07.13. 16:24
Last modified: 2025.02.27. 15:56

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