HP82104A Cardreader-"G" ROM Info


Looking for some info... Reading the MoHPC classified ads about an HP82104A card reader's that had a ROM version not containing a ROM "bug". HP must have at some point of their manufacture, had a ROM "bug" that was corrected by introducing a "G" version of the reader/ROM.

Does anyone know what the bug was/is, and how you can tell what the ROM version is for a card reader? I don't see a version # printed on the label of my example of 82104A. My original manual has version "C" but I thought that would be for the manual only.

Any help would be appreciated!


You can get the version number of your card reader by doing a "catalog" command on your 41. I'm not sure which catalog number to run, 2 I think. As it reads the functions and programs on each ROM you have plugged in to your 41 the first line of the listing tells the version number of what is plugged in. You are right to assume there were bugs in early card readers. The bugs are explained in the book "Extending Your HP-41." I don't have the book handy since I am in the US and my books are in Korea but I'm sure someone else can put an explanation here on the forum to help you out. I hope this helps. Randy


First, to check the ROM version, insert it into an HP-41, and execute catalog 2. You will see something like "CRD RDR 1G". If you have an HP-41CX, only the ROM headers will display, so this will come up after only a few entries, depending on how many other ports have something in them. If you have the HP-41C or CV, the program and function names will be displayed as well, so do this with nothing else in the other 3 ports, and you will see the card reader header first thing.

Secondly, there were several ROM versions, and the last one, version "1G", fixed a significant bug for users of the card reader and extended memory. The Card Reader "VERIFY" command would write over data stored in an extended memory module (HP82181A) that was in port 2. This could ruin a file, or the directory itself, obviously disastrous if the memory was being used.


And if CAT 2 just shows "CARD READER", I presume that is an early model card reader?


--- Les [http://www.lesbell.com.au]


Yes, I have seen early serial number card readers display "CARD READER" with no revision number. I believe that this is the first version.


Dan, Les and Randy, Thanks for the info. My check showed (lucky me!) the 1G version of the card reader. I will also check my "Extend Your HP-41" for any additional info.

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