Mattel IntelliVision II 5872 Manuel d'utilisateur télécharger pdf (Page 82)

Numeric zero, as opposed to the letter `O' (the 15th letter of the

English alphabet). In their unmodified forms they look a lot alike,

and various kluges invented to make them visually distinct have

compounded the confusion. If your zero is center-dotted and letter-O

is not, or if letter-O looks almost rectangular but zero looks more

like an American football stood on end (or the reverse), you're

probably looking at a modern character display (though the dotted zero

seems to have originated as an option on IBM 3270 controllers). If

your zero is slashed but letter-O is not, you're probably looking at

an old-style ASCII graphic set descended from the default typewheel on

the venerable ASR-33 Teletype (Scandinavians, for whom Ø is a letter,

curse this arrangement). (Interestingly, the slashed zero long

predates computers; Florian Cajori's monumental "A History of

Mathematical Notations" notes that it was used in the twelfth and

thirteenth centuries.) If letter-O has a slash across it and the zero

does not, your display is tuned for a very old convention used at IBM

and a few other early mainframe makers (Scandinavians curse this

arrangement even more, because it means two of their letters collide).

Some Burroughs/Unisys equipment displays a zero with a reversed slash.

Old CDC computers rendered letter O as an unbroken oval and 0 as an

oval broken at upper right and lower left. And yet another convention

common on early line printers left zero unornamented but added a tail

or hook to the letter-O so that it resembled an inverted Q or cursive

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Mattel IntelliVision II 5872 Manuel d'utilisateur Page 82