|Re: question on hp 42s|
Message #2 Posted by Vieira, Luiz C. (Brazil) on 5 Apr 2003, 10:24 a.m.,
in response to message #1 by lokhin
any user program written for the HP41 will run in any HP42S. There are fewer exceptions, mostly when some sort of errors occur, illegal math operations that would lead to erros when real numbers are your result set and some particular status flags are used. If you want full compatibility in math and stat you may "adjust" the HP42S to show only real numbers and to deal with fewer statistical registers. anyway, because of a bigger mantissa, expected rounding errors in original HP41 programs may not occur when they are loaded and ran in an hP42S. All of these facts must be taken into account.
If you intend using, say, X-Functions or any other system-related ROM routines, as far as I know it has not been done yet, because the only means to enter data in an HP42S is by using the keyboard. Even having access to RAM data directly (memory browser) and having the chance to directly alter bytes, you'll have to do it everytime memory is cleared. If you have to type in more than a couple of thousand "system" program lines, I think this is not pleasant. Anyway, dealing with matrices (and complex matrices) is easier than dealing with data files in X-Memory. And the basic HP42S has more memory than an HP41CX with two X-memory modules.
Many HP41 resources are available in the HP42S. If your HP42S is upgraded to 32K, better. But I cannot see an easy way to add new "functions" to the available internal set that is not time consuming (key strokes). Also, one should know a lot about the HP42S internals, and the first name that comes to mind is J.F. Garnier.
Sorry not helping that much.
Luiz C. Vieira - Brazil