How did punch card systems work? Professor Brailsford delves further into the era of mainframe computing with this hands-on look at punch cards.

Extra Material on Punch Cards:    • EXTRA BITS - More about Punch Cards -...  
Extra Material - behind the scenes:    • EXTRA BITS - Behind the scenes on Com...  

Mainframes to Unix:    • Mainframes and the Unix Revolution - ...  
Near to the Metal:    • Near to the Metal - Computerphile  

Addendum: "ICL punched cards actually have 12 rows -- not 11 as stated in the film. Choosing any two hole positions out of 12 gives 66 combinations -- which can represent 66 different characters. This in turn is more than enough for the 64 possibilities of a 6-bit character held in ICL computer memory. Also, some special characters could actually utilise three hole configurations adding further to the possibilities."

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This video was filmed and edited by Sean Riley.

Computer Science at the University of Nottingham: http://bit.ly/nottscomputer

Computerphile is a sister project to Brady Haran's Numberphile. See the full list of Brady's video projects at: http://bit.ly/bradychannels