Lexikon's History of Computing

Five Generations of Computers

In terms of technological developments over time, computers have been broadly classed into five generations.

The lines of distinction between each generation are not exact, and some overlap in technologies exists.

Although these designations are open to some controversy, as a general description of types of technology in use, the terms first, second, third, fourth and fifth generation are sometimes useful in providing a general perspective of some of the advancements in computing technology.

First Generation: Approximately 1944-1959

Characteristics: vacuum tubes

Second Generation: Approximately 1960-1964

Characteristics: transistors

Third Generation: Approximately 1964-1975

Characteristics: integrated circuits

Fourth Generation: Approx. 1975-onward

Characteristics: large scale integration

Fifth Generation: 1990's and future

Characteristics: very large integration

First Generation: 1944-1959

Characteristics:

(not all first generation computers had all these characteristics)

-vacuum tube based

-punched tape input or output

-about 1,000 circuits per cubic foot

Examples:

-Harvard Mark I (electromechanical)

-Whirlwind

-ENIAC

-EDSAC

-UNIVAC I, UNIVAC II, UNIVAC 1101

-RCA BIZMAC

-NCR CRC 102A, NCR CRC 102D

-Honeywell Datamatic 1000

-Burroughs E101, Burroughs 220

-IBM models 604, 650 (drum memory), 701, 702, 704, 705, 709

Second Generation: 1960-1964

Characteristics:

-used transistors

-about 100,000 circuits per foot

Examples:

-UNIVAC 1107, UNIVAC III

-RCA 501

-Philco Transact S-2000

-NCR 300 series

-IBM 7030 Stretch

-IBM 7070, 7080, 7090, 1400 series, 1600 series

-Honeywell 800, 400 series

-General Electric GE 635, 645, GE 200

-Control Data Corp. CDC 1604, 3600, 160A

-LARC

-Burroughs B5000, 200 series

Third Generation: 1964-1975

Characteristics:

-large scale integrated circuits

-10 million circuits per square foot

Examples:

-Burroughs 6700

-Control Data 3300, 6600, 7600

-Honeywell 200

-IBM System/360, System 3, System 7

-NCR Century Series

-RCA Spectra 70 series

-UNIVAC 9000 series

-General Electric GE 600 series, GE 235

Fourth Generation: 1975-Current

Characteristics:

-very large scale integration

-continued miniaturization

-billions of circuits per cubic foot

Examples:

-IBM System 3090, IBM RISC 6000, IBM RT

-ILLIAC IV

-Cray 2 XMP

-HP 9000

Fifth Generation: Current and Future

Characteristics:

Combinations of some or all of the following technologies:

-extremely large scale integration

-parallel processing

-high speed logic and memory chips

-high performance, micro-miniaturization

-voice/data integration; knowledge-based platforms

-artificial intelligence, expert systems

-virtual reality generation

-satellite links

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