4 ms·
I think I've seen some older content where the convention was reversed like this. Wikipedia's article on slashed zero claims that IBM and some other mainframes
by alexjm 6y ago
I think I've seen some older content where the convention was reversed like this. Wikipedia's article on slashed zero claims that IBM and some other mainframes put their slash on the letter O instead of the number 0. However, in a bit of circularity, its citation (1) is this same BASIC manual. Checking an IBM manual (2) for punching cards, neither 0 nor O has a slash. The manual is undated, but documents the model 26 keypunch from 1949 and not the model 29 keypunch from 1964, so it's probably older than this BASIC manual.
1: https://en.wikipedia.org/wiki/Slashed_zero#cite_ref-9 https://en.wikipedia.org/wiki/Slashed_zero#cite_ref-9
2: https://archive.org/details/bitsavers_ibmpunchedAnIntroductiontoIBMPunchedCardDataProces_2436138/page/n5/mode/2up https://archive.org/details/bitsavers_ibmpunchedAnIntroducti... (page 4, 15)
- Someone 6y agoOn IBM punched cards, the letters needn’t look very different, as you could always look at the punches (digits have only one punch; also look at the patterns for letters A-I, J-R, and S-Z) And yes, people learned that. Because the primary output of a puncher were the holes, not the printed text, maintenance of the ‘print’ part wasn’t always done well (ink smear or devices that ran out of ink), resulting in print output didn’t look remotely as clean as that manual shows.