James Tam

The history of computers and computing: Part II

The computers of the 20th century and the people behind those machines.

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Konrad Zuse

Developed a series of mechanical calculating machines (Z1, Z2, Z3, Z4).

He was the first person to construct a calculator that could run automatically

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The Bell Complex Number Calculator

The Bell Computer could add, subtract, multiply and divide complex numbers

Employed simple switches and flash bulbs

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The Bell Complex Number Calculator (continued)

It was the first machine to:

•handle multiple terminals

•be operated remotely

Photos courtesy of Bell Technologies Inc.

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The Bell Complex Number Calculator (continued)

The computer used it’s own form of binary, Binary Coded Decimal (BCD).

Decimal value BCD value

0 0011

1 0100

2 0101

3 0110

4 0111

5 1000

6 1001

7 1010

8 1011

9 1100

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The Harvard Mark I

Manufactured by IBM and was donated to Harvard University.

Extremely accurate

Used by the U.S. navy (bureau of ordinance)

Frequently used as a design model in subsequent machines.

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John Atanasoff, Clifford Berry, and the ABC (Atanasoff-Berry Computer)

Atanasoff needed a computer to perform specialized calculations

He got his inspiration for the ABC in a bar.

A photo of Clifford Berry and the ABC, courtesy of Dr. Atanasoff

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The ENIAC

Developed for the U.S. army at the Moore School of Electrical Engineering (University of Pennsylvania)

Picture from the History of Computing Technology by Michael R. Williams

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The ENIAC (continued)

Used vacuum tubes to store information

It was huge, complex and extremely expensive

All this could store one digit!

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Alan Turing

A British Mathematician

He worked at Bletchley Park as a code-breaker (contributed to the design of the machinery as well as applying his Mathematical knowledge)

An Enigma encoding machine

Pictures from the History of Computing Technology by Michael R. Williams

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The EDSAC (Electronic Delay Storage Automatic Calculator)

The first reliable computer to actually incorporate memory

(The first computer design conceived that incorporated memory was the EDVAC/Electronic Discrete Variable Arithmetic Computer but it was completed after the EDSAC).

Picture from the History of Computing Technology by Michael R. Williams

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EDSAC (continued)

First demonstrated in 1949 (ran at 500,000 Hz / 0.5 MHz)!

A spin-off of the EDSAC (called LEO / Lyons Electric Office) was the first computer to be used for commercial data processing.

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The Stretch

One of the first super computers

Pictures from the History of Computing Technology by Michael R. Williams

The whole “Stretch” Control panel for the Stretch

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Summary

Some of the more ground breaking computer systems and personalities of the 20th century.

•Konrad Zuse and the “Z” series of computers.

•The Bell Complex Number Calculator

•The Harvard Mark I

•Atanasoff, Berry and the ABC

•The ENIAC

•Alan Turing

•The EDSAC

•The Stretch