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Calendar Curiosities: It’s In The Cards


Today is Herman Hollerith’s birthday. He was born on 2/29/1860, which would make today his, erm, 37th birthday. Hollerith was the inventor of the punchcard. Remember those? Seriously old tech stuff. Nobody uses them anymore. But here’s the thing: Chances are the computer you’re using still contains at least the ghost of Hollerith’s punchcards.

See, Hollerith experimented with a bunch of different card formats, finally settling on a 3 1/4″ by 7 3/8″ card. Why? Because that was roughly the size of the US dollar bill at the time and there was a lot of existing infrastructure for handling things that size. These cards had a 45 column format, using round holes. Like this:

Hollerith’s Tabulating Machine Company merged with a couple other companies and eventually became IBM. IBM continued to use the Hollerith card size but found they could squeeze 80 columns of rectangular holes onto them.

That 80-column format carried over to text terminals. With the shape of existing CRT screens (which were based on TV picture tubes), they could manage 24 rows of 80 column text.

When computers started transitioning to graphics displays, the 80×24 was subdivided into its individual pixels, giving you 640×480. (The actual characters were 7×9 pixels, with a 1-pixel gap, giving you 8×10, but the vertical scanning was interlaced, so it was really 8×20. So 80*8=640 and 24*20=480. It works. Honest.) And 640×480 remained a graphics standard for quite some time. The 4:3 aspect ratio from 640×480 also shows up in the 800×600, 1024×768 and 1280×960 screen resolutions.

Of course now we’ve got wide-screen monitors and vertically-oriented handheld screens, so the whole 4:3 thing has started to fade away. But a lot of images and videos still use those older resolutions, which can (tenuously) be traced back to Herman Hollerith and his punchcards.

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