Computer History Museum

A trip to Silicon Valley will not be complete without a trip to the Computer History Museum. It has the largest collection of historical computers in the world and fascinating displays.

This building used to be the worldwide sales headquarters for Silicon Graphics.

The Computer History Museum building

Easily mistaken for a strange looking sofa.

Cray-1

Starting with something small, there is a display of old calculators.

Calculators

The most interesting piece is this rare HP calculator watch, introduced in 1977. This was the first HP calculator to use algebraic notation. Previous HP calculators used the Reverse Polish Notation, which many HP users think is superior.

HP-01 calculator watch

A display of personal computers. How many do you recognise?

Personal Computers

Invented by Herman Hollerith in 1889 to process the 1890 US census. It used punched cards to process the census results. The patent ended up in a company that was to become today’s International Business Machines (IBM).

Hollerith Census Machine
Manual card reader

The famous German code machine that was uncrackable at its time. Eventually, the codebreakers at Bletchley Park worked out how to break the code (through an amazing combination of intelligence, user error by the Nazi, and luck).

Enigma machine

Old school computing.

Punch cards

In the days before transistors, computers were constructed from vacuum tubes. These machines were large, generated a lot of heat, and were fairly unreliable.

Valves

A classic mainframe computer from the late 1960’s.

IBM 360

A minicomputer.

PDP-11

The Altair 8800 was the first microcomputer that was widely sold. Released in 1975, it was available in both kit form and assembled. Microsoft’s very first product was a Basic language interpreter for the Altair.

Altair 8800

The Apple 1 came along in 1976. The first Apple 1 computer was sold to enthuiasts as a pre-assembled board. All the owner had to do was to add a case, a keyboard and display.

Apple 1

This is the original Utah teapot that is used as a standard model in computer graphics. The computer model of it was created by Martin Newell in 1975 when he was at the University of Utah.

Teapot

Charles Babbage designed the difference engine in 1822, but it was never built because he couldn’t get funding for it. In 1989-1991 the London Science museum finally built it.

Difference engine

A printer was later constructed, along with a second difference engine. The original one is on permanent display at the London Science Museum. This second model was on tempory display at the Computer History Museum. I was fortunate to see being demonstrated here.

Difference engine printer

This is a closeup of the printing mechanism.

Difference engine printer

This is an example printout from the difference engine. The difference engine was mechanical and the only thing it was designed to do was to calculate logarithm tables. Today’s computers are electronic and do so many different things–but they too will one day become an exhibit at the Computer History Museum.

Difference engine output

See also

Science and technology photos
Other museums and places related to science and technology.

External links

Computer History Museum
Official Website of the Computer History Museum.