Question about HP 41CX Memory Allocation

[Les Bell]

(09-06-2014 05:44 AM)EdFab Wrote:  Incidentally, I get the display of 00 REG 219 whether the X Memory is installed or not. So how does the X Memory module come into play at all?

The idea you're missing is that Memory and Extended Memory are two different things.

The SIZE command re-allocates main memory, which is shared between memory registers and program storage (plus key assignments and alarms, but let's not make it too confusing). A 41CX has 319 registers of memory.

Extended Memory, on the other hand, is devoted to files. A 41CX has 124 registers of extended memory, and it appears that you have a double Extended Memory module, which brings your calc up to the maximum of 600 registers of X-MEM.

The two cannot be merged or traded off. Rather, you can save programs (SAVEP), blocks of registers (SAVER, SAVERX) or the current X register value (SAVEX) to a named file (the file name is usually in the ALPHA register) and you can retrieve them using GETP, GETR, GETRX and similar commands. Data files are created using the CRFLD command.

So, think of X-MEM as being file storage, and you'll have the right idea. You really need to get a manual, perhaps on the Museum DVD.