HP Forum Archive 06

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Why did the arithmetic keys switch sides? Message #1 Posted by Dave Shaffer on 21 July 2001, 12:32 p.m. On the original calculators (HP35 et al.), the arithmetic keys (+ - x divide) are on the left side of the keypad. The keys are similarly located on my 41's. However, on my HP11 these keys are on the right hand side of the keypad, as they seem to be for all (?) later calculators. For those of us (in the majority!) who are right-handed, it seems to me that having the arithmetic keys to the left of the numbers is most sensible. Did some left-handed HP engineer get into the calculator design about 1980 and change things around to his own chirality? Does anybody know why the change?

Re: Why did the arithmetic keys switch sides? Message #2 Posted by John Ioannidis on 22 July 2001, 5:45 p.m., in response to message #1 by Dave Shaffer This seems to have happened in 1981, when the 10C series was interoduced. The landscape-mode calculators had just four rows of keys, enough for the four arithmetic functions; it made sense to have the numeric keypad on the righ-hand-side of the keyboard (for the benefit of the righties), but it also made sense to have the +/-/x/: keys at the edge. Hence, the arithmetic keys switched sides. When HP went back to portrait-mode calculators, that change remained. This probably also has something to do with the fact that the ON switch was now just another button, at the lower-left corner of the calculator, where it has remained. The other major change that happened with the 10 series was that the ENTER key lost its uparrow, as the key was now vertical and a lone uparrow would have been ugly. The uparrow did not return with the HP28, probably because ENTER was now not just a stack manipulation key. /ji, feeling his Byzantine roots...

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