History of Computers - Colossus Computer

This page was created by Geoff Dunn.

The Colossus computer was the first programmable, digital, electronic, computing machine and was created in Britain, primarily London, with the purpose to break the German codes during WWII. For calculations, it used Vacuum Tubes.

Overview

Designed by mechanical engineer Thomas Flowers to solve a problem created by mathematician Max Newman, the first Colossus (Mark 1) had 1,500 valves (or vacuum tubes) used for calculation when at the time, the most complicated electronic devices only had 150 valves. A common misconception is that Alan Turing was a key figure in the design and building of the Colossus; he was not. Flowers anticipated a need for the computers and redesigned the Colossus to use 2,400 valves; the Colossus Mark 2 was later built and it operated about 5 times faster than the Mark 1. By the end of WWII, ten Colossi computers had been built and used with the purpose of decoding German codes intercepted over the radio, with an eleventh ready to be commissioned. Before the D-Day invasion on Normandy beaches, bombing runs were executed on the telephone and teleprinter landlines, forcing the Germans to use the radio as means of communication. The British were then able to intercept many more messages, giving them the knowledge that Hitler had indeed fallen for their ploy to convince him that the attack would be elsewhere. With Hitler's attention in the wrong place, the Allies were able to pull off a successful invasion. Although successful in its use of deciphering code, the Colossus computer only had that one use, and was not a general purpose computer like ENIAC or the Z3.

Significance

The significance of the Colossus computers lie in many areas. First and foremost, the Colossus computer was the start of programmable electronic digital computers. It may seem primitive relative to how far today's technology has advanced, but it was the most complex machine in its time. It led the way to versatile computers that can be programmed to handle many different functions. In a sense, the Colossus computer was the first modern computer because it used totally electronic and digital codes in programs.

A second significance is the role it played in deciphering, or breaking, the German codes during WWII, especially during the planning and execution of the D-Day invasion. It helped the Allies to victory, if not also decreasing the length of the war.