Retrotronik RAM card for HP 48GX

[rprosperi]

(07-01-2021 10:01 PM)Eric Rechlin Wrote:  

(07-01-2021 08:50 PM)Sylvain Cote Wrote:  I missed that one, anyway he was not shipping to Canada, I just sent him a message through his web site.
Question, how do you control the 128KB bank switching with the 2MB card in a HP-48GX ?

No need to worry about that on the GX (though of course it only works in slot 2). It divides cards into one port per 128 KB bank. Although 1 MB was the largest card HP sold for it, 2 MB cards work seamlessly. 4 MB cards mostly function but have a problem with the last port, so they generally aren't recommended.

To expand on Eric's comments:

When you put a 128KB card in a GX, you have: Port0, Port1, Port2
When you put a 1MB card in a GX, you have: Port0, Port1, Port2, Port3, Port4, Port5, Port6, Port7, Port8, Port9
When you put a 2MB card in a GX, you have: Port0 - Port17
When you put a 4MB card in a GX, you have: Port0 - Port32 (and not 33)

Technically, it is in fact bank switching, but its hidden from the user and 'invisible and seamless'. And since you can only move items between ports via the stack, it remains invisible even when using it.

These extended ports can best be used with a graphical file management tool such as:

PCT: https://www.hpcalc.org/details/2457

or, IMHO even better:

Filer48: https://www.hpcalc.org/details/4242