Quad Memory module changes "CAT" function

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Quad Memory module changes "CAT" function

Postby Jordan Orlando » Wed Apr 14, 2021 1:38 am

I just got a "Quad Memory" module (from eBay) for my recently-purchased 41C.

I already had two modules: "Standard" and "Math 1."

Without the new Quad Memory module, when I executed "CATALOG" "2," I got a full list of the programs on both of those modules (starting with the module names: the display would say "STANDARD" and "MATH1" and then list all the programs).

Bit with the Quad Memory module installed, the functionality is different: the selecting "CATALOG" (meaning, shift-"ENTER") has the display showing CAT ' (with a caret or single quote after the word. When I select 2 (to get the listing of the programs on the modules), it only names the modules, and then lists the programs that (apparently) are on the Quad Memory module (meaning, the previous owner had put a few programs on there).

I realized that, if I press "R/S" while the display was naming one of the ROM modules ("MATH1" for example), and then pressed "ENTER," I'LL get a catalog of that module's programs.

This is very interesting functionality that, as far as I can tell, isn't documented in the 41C manuals. The "CAT" display appearing with the caret (') after it, to indicate that the cataloging will now let you pick a ROM module, or, if you let them go by, will catalog the contents of the memory module (but only if one is installed) is a great feature, but I can't find it documented anywhere. Do I have this right?

Also, when you're viewing the catalog this way, the functionality changes: you can stop the "CATALOG" function (by pressing R/S) and then, by pressing "XEQ," run the program that was named when you stopped the catalog. (This doesn't seem to work, when the memory module is removed.) So far as I can tell, this isn't documented either.

Is "CAT ' " (with the caret) a different, better version of "CATALOG" that's only available when a memory module is present?

Thanks in advance for any help or advice — and, apologies if I'm being obtuse.

Jordan
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Re: Quad Memory module changes "CAT" function

Postby mike-stgt » Thu Apr 15, 2021 9:44 am

Hi,
looks as if your Quad Mem is more or something else than just a Quad Mem. I would check i) does it indeed add the expected amount of storage -- more memory for registers or more program space -- to your 41C (if not it is only the module housing labelled "Quad Mem"), and ii) what is listed in CAT 2 if nothing but this Quad Mem in question is plugged. If it shows nothing but the changed CAT (with the "inverted comma") -- in that case you have some nice analyse ahead.
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Re: Quad Memory module changes "CAT" function

Postby Jordan Orlando » Thu Apr 15, 2021 6:25 pm

mike-stgt wrote:Hi,
looks as if your Quad Mem is more or something else than just a Quad Mem. I would check i) does it indeed add the expected amount of storage -- more memory for registers or more program space -- to your 41C (if not it is only the module housing labelled "Quad Mem"), and ii) what is listed in CAT 2 if nothing but this Quad Mem in question is plugged. If it shows nothing but the changed CAT (with the "inverted comma") -- in that case you have some nice analyse ahead.


Thanks so much for responding!

My module is an 82170A — a normal "Quad Module;" not the later enhanced one. It does indeed show other programs.

It adds more registers.
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Re: Quad Memory module changes "CAT" function

Postby rprosperi » Fri Apr 16, 2021 12:39 pm

A. What is the "later, enhanced one" version of the Quad MM you referred to?

B. The "CAT ' " you see is exactly the way the CCD Module enhanced the built-in CAT function. You noted that when in this mode, you see only the module headers as you SST your way through, but did you notice if there are any extra modules listed, as compared to when the Quad MM is not installed?

In the 80's there were companies that modified modules, combining multiple ROMs, or combining a ROM into a RAM module. While it's hard to imagine someone risked a rare and expensive CCD module this way, it is possible, and if so, the CCD module header would appear in the CAT '2 header listing.
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Re: Quad Memory module changes "CAT" function

Postby Jordan Orlando » Fri Apr 16, 2021 11:30 pm

rprosperi wrote:A. What is the "later, enhanced one" version of the Quad MM you referred to?

B. The "CAT ' " you see is exactly the way the CCD Module enhanced the built-in CAT function. You noted that when in this mode, you see only the module headers as you SST your way through, but did you notice if there are any extra modules listed, as compared to when the Quad MM is not installed?

In the 80's there were companies that modified modules, combining multiple ROMs, or combining a ROM into a RAM module. While it's hard to imagine someone risked a rare and expensive CCD module this way, it is possible, and if so, the CCD module header would appear in the CAT '2 header listing.


Thanks for responding, and apologies for any confusion or ambiguity.

The "later, enhanced one" I'm referring to is the 82180A — according to this page https://www.keesvandersanden.nl/calculators/hp41_modules.php it "adds 47 useful functions to those already available on the HP-41 calculator.and also provides it with extended memory. The number of added registers is 127." (There's a link to a scan of the card that comes with the module, listing all its extra functions.)

To be clear: you're saying that the caret after "CAT" in the display generally indicates the presence of one of those third-party enhanced CCD modules?

ADDENDUM: I now understand that you're referring to the "Computer Club Deutschland" module — I looked it up in the Extend your HP-41 book, which is very informative. Thanks again for weighing in.
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Re: Quad Memory module changes "CAT" function

Postby Garth » Sat Apr 17, 2021 1:09 am

Note that extended memory is different and separate from expanded main memory. The 82180A is not for expanding main memory, but for extended memory which is for files. On the 41cx, your Extended Memory files will show up in CAT 4. On 41c and cv, you'll use EMDIR (Extended Memory DIRectory).
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Re: Quad Memory module changes "CAT" function

Postby Jordan Orlando » Sat Apr 17, 2021 1:12 am

Garth wrote:Note that extended memory is different and separate from expanded main memory. The 82180A is not for expanding main memory, but for extended memory which is for files. On the 41cx, your Extended Memory files will show up in CAT 4. On 41c and cv, you'll use EMDIR (Extended Memory DIRectory).


Whereas the 82170A — the one I've got — simply adds more registers, right?

(Taking into account the ambiguity of what, exactly, is on this particular one I got — since it adds the caret after the "CAT" function, and changes the CAT function in the other ways I mentioned.)
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Re: Quad Memory module changes "CAT" function

Postby Garth » Sat Apr 17, 2021 1:18 am

The quad memory module which I think is what you have only adds to main memory. It does not have anything to do with Extended Memory.
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Re: Quad Memory module changes "CAT" function

Postby Jordan Orlando » Sat Apr 17, 2021 1:21 am

Garth wrote:The quad memory module which I think is what you have only adds to main memory. It does not have anything to do with Extended Memory.


Right, as I figured; thanks.

I assume I can trust the printing on the outside of the module, right? I'm not familiar with how people "modded" them — if it's like (say) Atari roms, they could use existing HP enclosures around new chips or re-flashed chips (if these are the kind of ROM chips that can be UV flashed).

Thanks for responding, again.
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Re: Quad Memory module changes "CAT" function

Postby Garth » Sat Apr 17, 2021 2:17 am

The most common mod I know of is building two Extended-Memory modules together, or building them into the shell of an Extended-Memory/Extended Functions module (which is what the 82180 is, but what I said earlier was misleading; the Extended Memory modules aren't any good without the Extended Functions to access them). I have a 41cx. The cx has the Extended Functions module built in which also has the first 127 usable registers of extended memory, and then I have a double Extended Memory module plugged in, adding 2x238 usable registers, for a total of 603 usable extended-memory registers, or 4221 bytes. (The cx also comes with main memory full, ie, 320 registers, or 2240 bytes). I also have an HP-IL module with the Extended I/O module added into the same shell. (The cx has more than that built in too though, including a text editor.)

One of the modern hardware modules with flash is made by Diego and mounted in shells of the lesser-desired modules like the single memory module, the 82106A which is only useful for the 41c. Still, the shells are in short supply; so when I bought a Clonix-D from him, I sent him one of these that I had bought cheap on eBay to put it into. See https://www.clonix41.org/ . In mine, I have the Advantage, ZENROM, 41z, Warp_Core, and Library 4 module images. So with one of my ports still being empty, a CAT 2 on the monitor fed by the HP92198 80-column HPIL video interface looks like this:
CAT2_12-12-17.jpg
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Re: Quad Memory module changes "CAT" function

Postby Jordan Orlando » Sat Apr 17, 2021 2:47 am

That's interesting: module modding is dependent on access to the old shells. I guess that stands to reason.

I'm slowly getting acclimated to the basic ideas of how all of this architecture works. It's a fascinating sidetrack in computing technology — "sidetrack" meaning that not only is it set up in ways that seems unusual in the context of modern computing — it's unusual in the context of 1979 computing, too.

I do remember how, in those days (when I was in high school) the home computing world hadn't yet coalesced into the kind of centralized architectures that are available today — TRS-80, Commodore, Apple and Atari all had different "platforms" (if the word even applies), although they each relied heavily on their own version of BASIC. Atari's tech was most like HPs insofar as they used ROM cartridges (which were incompatible with the similar cartridges they used for their game systems).

What HP was doing was very different from all of those others, which of course makes sense given their roots in the engineering world, where portability and durability were more important than speed. But it's interesting how HP converged with the others and ended up with many of the same solutions in terms of expansion; programming; distribution of software, etc.
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