HP Forum Archive 18

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combine 41c memory modules? Message #1 Posted by sylvandb on 17 Nov 2007, 7:18 p.m. Can 41c memory modules (82106a) be combined? Either multiple units into one module case or actually installed inside the calculator so as to leave more ports available? (Don't suggest buying a quad-mem, that isn't the point. :) ) Thanks, sdb

Another question on memory modules Message #2 Posted by Palmer O. Hanson, Jr. on 17 Nov 2007, 9:59 p.m., in response to message #1 by sylvandb Can the memory modules be used to transfer programs or data from onr machine to another?

Re: Another question on memory modules Message #3 Posted by sylvandb on 18 Nov 2007, 12:27 a.m., in response to message #2 by Palmer O. Hanson, Jr. Quote: Can the memory modules be used to transfer programs or data from onr machine to another? Sometimes, if you are quick enough, the contents of the memory will have enough power to retain their contents. It was not a design criterion. (I've wondered about adding a little supercap in there...) The other issue is that some memory is onboard, and some is in the module, so you have to be very, very careful with data alignment. Remember, the 41c is late 1970's technology. sdb

Re: Another question on memory modules Message #4 Posted by Eric Smith on 18 Nov 2007, 2:01 a.m., in response to message #3 by sylvandb People used to add capacitors to the modules "back in the day". They weren't supercaps, though, since those didn't yet exist.

Re: Another question on HP-41 memory modules Message #5 Posted by Karl Schneider on 18 Nov 2007, 12:38 a.m., in response to message #2 by Palmer O. Hanson, Jr. Hi, Palmer -- I've been able to transfer programs between two HP-41C/CV's using an HP 82180A X Functions module. The user must quickly transfer the module containing the program file from one unit to another, or the data may disappear. My attempt to transfer a program file on an HP 82181A Extended Memory module from an HP-41CX to an HP-41C/CV with an X Functions module exactly filled, was unsuccessful. The contents of the Extended Memory module seemed to evaporate as soon as it was removed. I've noted that the contents of a Quad Memory module will also evaporate as soon as it is removed, so I'd doubt that an ordinary Memory Module will perform any better. -- KS

Re: Another question on HP-41 memory modules Message #6 Posted by Eric Smith on 18 Nov 2007, 2:00 a.m., in response to message #5 by Karl Schneider Quote: My attempt to transfer a program file on an HP 82181A Extended Memory module from an HP-41CX to an HP-41C/CV with an X Functions module exactly filled, was unsuccessful. The contents of the Extended Memory module seemed to evaporate as soon as it was removed. If the calc you were transferring the XMEM into didn't also have an XMEM installed (to be replaced) and the base XFN module full, it won't think the file chain continues into the XMEM. And the XMEM needs to be transferred into the same kind of port (left vs. right).

Re: Another question on HP-41 memory modules Message #7 Posted by Karl Schneider on 18 Nov 2007, 5:35 p.m., in response to message #6 by Eric Smith Hi, Eric -- Quote: If the calc you were transferring the XMEM into didn't also have an XMEM installed (to be replaced) It did not, unfortunately, although I do have two X-Mem modules. Quote: and the base XFN module full, That's what I tried to ensure: exactly 124 registers used on both the HP-41CX built-in X-mem and the X-Functions memory. Quote: it won't think the file chain continues into the XMEM. And the XMEM needs to be transferred into the same kind of port (left vs. right). I'm not sure if I did that. With your helpful tips, I might try it again sometime. Thank you. It's certainly easier, however, to use the card reader for that purpose; I have a working, refurbished one. -- KS

Re: Another question on HP-41 memory modules Message #8 Posted by Eric Smith on 18 Nov 2007, 10:33 p.m., in response to message #7 by Karl Schneider I agree that the card reader (or HP-IL) is easier, but I can imagine cases where they might not be available. If you need to transfer more than will fit in the XFN between two 41C/CV (but not 41CX), best bet is to transfer the XFN and XMEM modules together. Just make sure that any "left" XMEM stays left, and right stays right, since that controls the addressing.

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