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: https://www.youtube.com/watch?v=lkSGMrH5Kic Extra Material - behind the scenes: https://www.youtube.com/watch?v=Wi326Leuemg Mainframes to Unix: https://www.youtube.com/watch?v=-rPPqm44xLs Near to the Metal: https://www.youtube.com/watch?v=uNuFVq5QeRk 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." http://www.facebook.com/computerphile https://twitter.com/computer_phile 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