Kernel Summit 2008 - an advance view [LWN.net]

Kernel Summit 2008 - an advance view

Posted Aug 30, 2007 16:52 UTC (Thu) by AJWM (guest, #15888)
In reply to: Kernel Summit 2008 - an advance view by aleXXX
Parent article: Kernel Summit 2007 - an advance view

The 80-columns of course is legacy from punch card (Hollerith card) days, which was inherited by most dumb terminals (24 or 25 lines of 80 chars -- which xterm by default duplicates). There was also a brief period where a computer manufacturer (I think IBM, but could be wrong) introduced a 96-column punch card (different shape overall, not just 20% wider).

The relationship could also derive from typing: using skinny (1/4") margins to get 8" lines on an 8.5x11 page (US letter size), a courier typewriter at 10 chars/inch would fit 80 chars to the line (and 6 lines/inch). A "elite" typewriter, at 12 cpi would fit 96 chars on that same line (and 8 lines/inch).

If you really wanted to go to wide lines, there's the 132 columns (characters) that was standard for line printer output back in the day.

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Kernel Summit 2008 - an advance view

Posted Aug 30, 2007 17:20 UTC (Thu) by jschrod (subscriber, #1646) [Link]

You should note that typography research recommends to use at most 60-70 characters per line for readability. Taking indentation into account (but also not forgetting about comments) that translates to ca. 80-90 characters in source files.

There's more to this limit than punch cards.

Joachim

Kernel Summit 2008 - an advance view

Posted Aug 30, 2007 19:12 UTC (Thu) by AJWM (guest, #15888) [Link]

Oh, I'm not advocating >80 char lines in source code. Heck, I used to program a lot in APL, 20 characters ought to be more than enough for anyone ;-)

80 column terminals

Posted Sep 1, 2007 0:21 UTC (Sat) by giraffedata (subscriber, #1954) [Link]

It's definitely from Hollerith cards. People didn't use the early terminals to type memos, so even if there were a custom of typing with 1/4" margins (which I'm pretty sure there never was), it would not have influenced terminal design. What they did with terminals was type out (or type in) datasets that otherwise were stored on Hollerith cards: columns of numbers, source code, etc.

Block sizes on tape and disk were also multiples of 80 bytes for a long, long time for the same reason.

For those who haven't heard the story of why a Hollerith card is 80 columns: It's just what happened to fit on a card of that size with machinery of the day. And the size of the card was determined by the size of US currency, because there were storage boxes and such for that size.