Which ROM images?

Programs for HP-41

Which ROM images?

Postby montedalrymple » Tue Jan 12, 2010 4:06 am

I am getting close to programming the memory on my new 41 CPU replacement board, but would like to get input on which ROM images to
include/exclude. Does anyone care to comment? Right now I have most of the images on this website included, but perhaps this is too much...
The board includes functions to "plug in" any of the included images into any port.

If you don't know what I'm talking about, look at the appendices in the NEWT microprocessor manual on this site, or the updated one at

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Re: Which ROM images?

Postby Garth » Wed Jan 20, 2010 8:07 am

Since there are so many modules and so many people who know a much wider range of them than I, I sat back waiting for someone else to answer, but no one has-- so I'll jump in.

I have a 41cx with an Advantage module, ZENROM, double Extended Memory, and HPIL/Extended I/O combined module, meaning six altogether. The cx of course already has the Time module and Extended Functions module built in, plus the quadmem so main memory is maxed out. The cx's text editor (which is not available in any module) is also nice for several small applications, but is too slow otherwise. Altogether that's kind of like a 41c with a dozen modules all at once, if that were possible. I just recently got the double Extended Memory, and someone implied it might not work with the HPIL/Ext I/O combined module. I haven't tried it yet interfacing to external equipment, and I don't know the rules for combining modules; but from looking at Catalog 2, it looks like it's all fine.

I use the ZENROM for the easy synthetic programming, but I don't have the type of memory to use its assembler and do any MCode development. The CCD module is apparently the cat's meow, but I guess I have a lot of its functionality, and some of it further improved, in the Advantage and ZENROM. I understand the CCD's manual, if it's the one I'm thinking of, is nearly 500 pages, and truly a labor of love. I think the PPC and Paname modules are related.

Ángel Martin's new 41Z module is one I'm looking forward to using. It's mainly for complex-number operations-- and it has tons-- about 70, including all the comparisons, stack operations (with all the indirects!), roots, hyperbolics, ZAVIEW (the "Z" meaning "complex"), geometry, etc.! The Advantage module has complex-number operations, but it's pretty clumsy compared to the 41Z. The 41Z gives another keyboard, an additional user keyboard if I understand it correctly, in order to make it quicker to reach all the complex-number functions, and another shift key, the old Σ+ key which almost no one uses except by re-assigning it. It gives a true 4-level complex stack, plus a complex LastX, if I understand it correctly. The Advantage module only used the native stack, limiting you to two levels when it does complex numbers.

Although there are more modules that might interest me and I do want to get one of the larger modern memories (Clonix? MLDL2000? Something else?) that can be loaded with ROM images, there are an awful lot of modules that would not be of any use to most people. There's a module list at http://calc.fjk.ch/db/hp41mod.php . Auto finance, car sales, real estate, securities, modules geared toward particular aircraft, games (which have no business being on any of my computers), nuclear medicine, medication dosage, GMAC, logging... the list goes on and on.

Even the HP 44468A data-acquisition pac which kind of puts a front panel on the HP3421A data-acquisition unit is not necessary if you don't mind looking up the 3421A commands in the manual as you're programming, which is what I did in my first automated test equipment setup controlled by the 41. Later I used a lot of other HPIB (IEEE-488) lab instrumentation. The Exteded IL and IL Development modules are a couple that might interest me.

There is Forth available for the 41, but in spite of Forth being my favorite language, it doesn't look like the kernels written for the 41 so far are very good, and I have to question whether the 41's unusual register, bus, and memory structure, and its poor handling of text files for source code could ever lend themselves well to Forth.

I never got the bar-code wand, and the only HPIL printer I ever used was the ThinkJet (now I just use the regular ol' Epson printer, going through an interface converter), but I always thought the bar code capability was a really nifty way to share programs. At a user group meeting, all you needed for making a lot of copies of programs to distribute was a photocopier. Now of course we have the internet so people don't travel to get together as much, but short of having a USB connection, you could still download and print bar-code images for the 41. The bar-code wand was rather hard on batteries. I suppose that now that LEDs are far more efficient, you could open up the wand and replace the LED and increase its series resistor so you could get the same amount of light with far less power and make the batteries last longer.
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Re: Which ROM images?

Postby Klaws » Tue May 18, 2010 6:02 pm

I suppose that now that LEDs are far more efficient, you could open up the wand and replace the LED and increase its series resistor so you could get the same amount of light with far less power and make the batteries last longer.

I guess not - AFAIR, sensor and LED were part of a single integrated device (which also included the optics). No way to exchange the LED separately!

- Klaus
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