A ROM emulator for the 71B

[rprosperi]

Dave really likes checksums being correct... even if no one has a diag module to see if the checksum is correct. Passing a diag test seems to be the ONLY reason these checksums were created, as the OS ignores them. But chaining the BASIC programs is an important step, if you will be including any of those in the ROM image (and which will run from the ROM). But he is right, I just didn't want to muddy the picture.

Another simple technique Paul Berger found is to use ROMCOPY twice, once from IRAM->Disk File and then from the same Disk File->IRAM, which will clear the IRAM signature in the final image and place checksums properly, so the OS understands the image is ROM and not IRAM. This will also chain (also called 'compile' in the ROMCOPY docs) the BASIC programs.

Both work, the former is quicker and easier.

You can (and should) walk thru the ROM creation process, using a 4K image with several small LEX files, just to work through the process.

I think it would be better in the case, if that can be accommodated without changes to the board, but that's certainly a persnickety personal preference. The hole for the header and a cap makes it neat, tidy and tight (sorry, I taught Scout knots for too many years).