Big ROM - 41 System DEMO ROM


A couple of weeks ago Gene was asking about big programs for a ROM. Coincidentally I got a cassette with the 41 System DEMO and thought about putting it in a ROM image - pretty big as it's about 17k bytes (well, words).

It really is an archaeological finding, as it requires a real system (i.e. won't work on emulators like V41; nor without an HP-IL plus printer at the very least).

The tape I got had a few tricky points so I had to restore (what I think was) the original code manually - time consuming, albeit not complicated. Also didn't try the VIDEO, PLOTTER, or PRNT80 demos since I don't have access to any of those peripherals required.

So FWIW, the Module is ready to go. Should be posted in a few days, email me if you can't wait.



Hola, Ángel. ¿Que tal?

Well, I guess that 'Thank you!' is not enough to express my (and many others, I know) thankfulness after so much of what you have done, but they are still good words.

I'll 'grab' an HPIL with a (possibly working) HP82162A in November, so I'll try the 'BIGROM' then. Based on what I've been reading about, I believe this is not a silly question: would this BIGROM work in a 41CL? I mean, not that the system might/should be tested, instead if there is any kind of incompatibilities.


Luiz (Brasil)

Edited: 14 Oct 2012, 12:44 p.m.


Hola Luiz, glad it´s interesting to you (and others) - that´s the idea, even if it´s such an ancient demo it´s fun to watch.

I use the CL in fact, 100% compatible using TURBOX of course. As I said, I can't test the VIDEO and PLOTTER but should also work.



Hello Angel,

I can test the ROM if you want.

I have all the accessories and peripherals that you need for this system demo rom.

Best regards,



Dear Angle,

Question : Is the HP82166A IL-Converter included to the HP41 - HP-IL setup ?

Now I operate my IL2000 Interface, which is based on the IL Converter
with 41CL as system controller.

In practical use now I get an speed up effect of 20 x in turbo mode - - this works great for any advanced interface application like data logger, measurement, control applications...

Furthermore I use same speed up effect when operating the IL-Plotter - again for this HP-IL device the 41CL is an great improvement...

With best regards - Christoph Klug

HP-41 I/O-Board & IL2000 Interface System

Edited: 15 Oct 2012, 1:38 p.m.


Hallo Christoph, the System Demo is really a sales-oriented demonstration - more than a technical one. It mostly has text (lots of text!) describing the features of the system components, plus a couple of nice little tricks - but nothing really fancy.

So yes, there's a mention to the HP82166 in the "GPIOX" program within the ROM, but as I said it's just text.

There's still about 1k available in the module - so maybe you have some ideas of a nice candidate to include, perhaps using the advanced stuff? Let me know.

Viele Gruesse,

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