[TRS-80 Model 4P] > If it will do it with a blank disk, then the statements that it "doesn't > have ROMs" are more faulty. It obviously has SOME ROMs, to start up enough > to try to boot. But, this would tend towards disproving the statements > that it doesn't have BASIC in ROM. > And, if it has the "POKE" command, then all sorts of wondrous things > become more easily available.
I don't have a 4P, only the desktop Model 4 which of course is known to have 14K of ROM containing BASIC. But I've been reading the 4P service manual which has a good description of the boot process. There is 4K of ROM in a 4P, to extend it to a larger ROM would involve major-ish hardware modifications. So I think we can discount this. However the boot process checks to see if it's likely that the Model 3 ROM image is needed and if so it will load it from disk very early on in the boot sequence. So my guess is that the disk that started all this had a valid and readable ROM image on it, this was loaded, and there was then an error loading the rest of the OS so the machine ran said BASIC. Incidentally, one feature of the 4P boot that I didn't know about is that it's possible to boot from the RS232 port. That is to download (plain binary I think) and run a program from there without a disk. -tony
