41CL and PPC ROM


During the HHC2011 conference, Richard talked about the PPC ROM and what it took to get it out the door. I was a member of the PPC during that time and I remember that there were some minor bugs in the PPC ROM discovered after the ROM mask was made. Since it's now a part of the 41CL, has the PPC ROM image been patched so those bugs are no longer there? I don't remember if any subsequent 41C apps were written that depended upon the PPC bugs.

Which brings up my second question. Have the ROM images loaded into the 41CL been corrected for known bugs so that it's actually better to have the 41CL than the original ROM plug-in modules?



I did not do any editing. But it is easy to patch things in

Flash. Beta users had to patch the CL Extra Functions several

times before everything was working right.



The *only* bug of which I was ever aware was in the BE Block Exchange routine. It ended a loop with a GTO BE global label call rather than a GTO local label number. This slowed down the exchange routine, but did not affect results.

I am not aware of *any* other bugs.

Anyone have some? :-)


Not bugs per se, but there are problems with some of the routines if you have any "buffers" in the memory. This most commonly case occurs when using Time Module/41CX alarms, which are stored in a buffer. The buffers occupy registers just below the key assignments, and synthetic programs (including those in the PPC ROM) that manipulate the key assignments or program memory may corrupt the buffers leading to lost data or crashes.

The reason I say that these aren't bugs is that the PPC ROM was written before there were any ROMs available that used buffers, so there was no way for the programmers to know that there would be a problem.

This is an example of why HP said that if PPC put synthetics in the ROM, that HP would not accept any responsibility for the results.


As much as I love the PPC ROM (being an active PPC member during its gestation I lived all the excitement) I must say it's been superseded by more capable and vastly more interesting modules. Consider for instance the CCD Module and the HEPAX - both monumental and trend-setting.

Some others also added excellent contributions to the "state of the art" back them (and even now).- think of the ground-breaking AECROM, the ZENROM and ZENROM Programmer, etc. The expandability of the 41 series matched with the ability to program MCODE made all the difference to me.

Easy to say for somebody still making new ones :-)

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