HP-41CV Card reader essential?

[RPNerd]

Hi Chris,

Going by your username I would guess that you're not too far from me (Lancs).

A card reader is definitely not necessary but it does help safeguard programs that you've written and data that you've accumulated from loss of power. You are correct in thinking of X-Mem as a kind of external storage facility in that the 41 can save stuff to it and retrieve stuff from it later but cannot work directly with it.

Take a good look at the manuals for the CV and the X-Func and X-Mem modules. You can find them here: https://literature.hpcalc.org/#model:41CV

The contents of your X-Mem is preserved as long as there's power in the batteries. If you remove the batteries, it's lost.

Quick tip to help mitigate this: find yourself a second battery holder (thecalculatorstore.com sells them 3D-printed). When the time comes to replace the batteries, fill the spare battery holder with a set first, then simply swap old for new. The operation takes no more than 3-4 seconds and the memory contents should survive loss of power that long.