What has the DM41 extra over the HP42s?

[hth]

(11-05-2020 01:14 PM)Marco Polo Wrote:  I would like to highlight one aspect which makes Free42/DM42 preferable when compared to DM41x. IMHO.
Free42 is actively mantained with prompt bug fixes and improvements.
DM41x relies on HP41 roms, and i am not aware about further development. I might be wrong...

I do things with the HP-41 ROMs.

First of all, it is of course impossible to alter the ones in existing genuine original HP-41. Well, not impossible on the older hardware, but hardly a practical route. Anyway, read on.

For the firmware itself I have recreated the source and it is buildable. I have made a version that corrects bugs in the original ROMs and also added a new feature (more extended memory). This requires the HP-41CL and is available from the 41CL update channel. I have asked about the possibility to do similar things on the DM41X, but it is not allowed there at the moment.

For further extensions there is the OS4 module which you can find on Github. This module works with any HP-41 model and can be seen as a further development of the firmware. OS4 provides frameworks for custom keyboards which allows you to replace the built-in standard keyboard using a very flexible mechanism called shells. This makes it possible to turn your HP-41 basically anything else, for example an HP-16C. No custom menus or menus for that matter, just plain native full keyboard control with press down and hold keys that says what they will do. OS4 provides programmable prompting functions (single and dual arguments) and it eliminates the FAT limitation of 64 functions. The number of function you put in a module is only limited by available memory.

At the moment I am not doing mainframe/firmware fixes as I do not have any bugs that I think need to be fixed. Please let me know if there are. OS4 is being worked on at the moment, though most HP-41 work on that side is on its companion module (Boost).

The reason this is possible is thanks to the open nature of the HP-41, made possible by HP a long time ago. It is also helped by the fact that the HP-41 is written with extensibility in mind and in a language that allows it, it is not a C program. Thus, the HP-41 is a very nice open retro programming environment and a hacker's dream. You are not constrained by the user language you can read about in the owner's manual, you can go much further if you like.

References:
https://www.hpmuseum.org/forum/thread-13...=mainframe
https://github.com/hth313/OS4
https://github.com/hth313/boost41
https://github.com/hth313/ladybug