Posts: 109
Threads: 6
Joined: Jan 1970
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
Posts: 351
Threads: 49
Joined: Mar 2008
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.