Re: hp41cv memory modules Message #4 Posted by Dieter on 6 Nov 2013, 4:12 p.m., in response to message #1 by tim peterson
The original 41C (C, not CV or CX) came with 448 bytes of RAM (yes, minus three permamently occupied bytes). It could be upgraded to a maximum of 2240 bytes. There were various RAM-modules: Up to four 82106A modules with 448 bytes each could be added, or two Double-RAM modules with 896 bytes, or one Quad-RAM 82170A with 1792 bytes.
All these RAM modules can not be used on a 41CV or 41CX, as these machines already have the maximum amount of memory built in. They come with 2240 factory-installed bytes. So there is no use for any of these modules in a 41CV or 41CX.
Extended memory ("X-memory") is a different story. It is added to the conventional RAM and the user may transfer data between regular RAM and X-memory. You may think of it as a kind of RAM-Drive (well, sort of). To use X-Memory, you plug in a 82180A X-Functions/X-Memory module. This module adds a set of handy additional functions (hence the name X-functions), and it also provides the required commands to deal with X-memory. A certain amount of X-memory already is built into the module. Further X-memory modules 82181A can be added to expand X-memory. So the 82180A is always required, and one or more 82181A modules are optional.
This means you can neither use the 82180A (not required and not useable with the 41CV) nor the 82181A (requires a 82180A X-functions/X-memory module).
Dieter
Edited: 6 Nov 2013, 4:15 p.m.
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