John Biggs writes about the father of computer science:

Today’s Google Doodle is a working Turing machine that contains six puzzles. Sophia Foster-Dimino on Google’s Doodle team built the app in honor of Alan Turing’s 100th birthday.

What’s a Turing machine? It’s not an actual machine, per se, but a thought experiment that allowed for the advent of digital computing.

…an unlimited memory capacity obtained in the form of an infinite tape marked out into squares, on each of which a symbol could be printed. At any moment there is one symbol in the machine; it is called the scanned symbol. The machine can alter the scanned symbol and its behavior is in part determined by that symbol, but the symbols on the tape elsewhere do not affect the behaviour of the machine. However, the tape can be moved back and forth through the machine, this being one of the elementary operations of the machine. Any symbol on the tape may therefore eventually have an innings.

Turing went on to head the team at Bletchley Park that decoded Germany’s Enigma encryption machine, thereby turning the tide of the war. The British government subsequently sentenced him for “gross indecency” – homosexuality – and offered him prison or chemical castration. He chose the latter and killed himself two years later.

Former UK Prime Minister Gordon Brown posthumously apologized to Turing in 2009.

Turing Machines are the fundamental theory behind the computers we use today: http://gigaom.com/europe/why-we-owe-it-all-to-alan-turing/

Hard to believe humans have only had them such a short amount of time compared with our overall history.

Happy birthday, Alan Turing!