Scott, After reading your shopping list of wants, I think a REX is a great solution, and developing an option ROM is really your best path. But you don't need to do a rip and replace on the main rom to get there.
I personally think it is a very bad idea to replace the stock MAIN ROM, with REX. It was an aspect of the original REX design, with the thinking that, well, if you had a huge flash chip what could you do with it? Yes you could store OPTION ROM software, and yes you could back up the RAM nicely. But what about patched MAIN ROMs? There are some defects with the original MAIN ROM: -- Y2K -- miscalculation of PI (I believe) So it sounds like a neat idea. Why not make REX take over the MAIN ROM? So I did make that possible however.. The problem comes when you have an issue with REX, and it is providing the boot code. If REX malfunctions, you can brick your laptop very easily. So then you need to open it up, insert the original ROM, etc. A lot of pain for not much gain. Oh, and by the way all versions of REX fix the Y2K display problem. So, imho, there isn't any real benefit to changing the MAIN ROM, unless having Pi to only something like 10 digits isn't good enough;). In REX# and REXCPM, I have removed this "rom replacement" function. Others may disagree with me. To each their own. Please see further comments below. Steve On Sat, Dec 19, 2020 at 6:35 PM Scott McDonnell <mcdonnell.j...@comcast.net> wrote: > Will do. Just so I understand, the Rex replaces the main rom? The M100 > will boot directly from the Rex? And with the Rex, I can customize my own > applications, autolaunch, etc? This goes into the DVI socket on the bottom? > REX# (and REXCPM and REXclassic) are all OPTION ROM devices. They generally plug into the option rom socket. Generally REX makes available to the laptop selectable option rom software, and a variety of other functions. A typical REX install does NOT require removal of the MAIN ROM, nor is it needed. > > > I had looked at it before, but the descriptions seem to be written for > people that are already well into the Model 100 and not very clear to a > TRS-80 newbie like me. :) > Yes, my documentation generally assumes a good level of M100 knowledge. I believe there is enough other documentation out there. > > > What I would like to be able to do: > > Replace the main ROM > OK. Why? Option ROMs are pretty straightforward to develop. M100 has a good autoboot function built in so you can jump straight into your code. There is a well used and well documented set of information on how to make an option rom. > Custom menu > doable via an option ROM. > My apps not stored in RAM dependent on battery > Again doable via an option rom. with REX, you can store it in flash, and easily re-load bug fix versions as you develop. If you blow away the main rom you lose all the benefits of having that library of software routines to call. Autolauch a program at power on (and preferably be able to exit out to menu > if wanted) > Again, ideal use case for an option rom. Ease transfer of files back and forth with a PC (TPDD emulator or Trashtalk) > TS-DOS is also an option rom. > > > Thank you to everyone that has replied. > Really it sounds like a REX is ideal. > >
