Stuttgart HP Meeting 2024 (replacement Allschwil)

[J-F Garnier]

(10-21-2024 03:33 PM)Dave Frederickson Wrote:  Then there's type C, like HP, who identified the Finance ROM as an IRAM and not a ROM. How should this ROM image be archived?

Checksums are used by the Diagnostic ROM and the CMTTOOLS.

To add to the confusion, the HP and CMT checksums are not the same !
HP was using a checksum byte for each 16k block, because they used 16k ROM chips and it was a way to know which chip was bad in a module.
Because the CMT modules were based on a 32k or 64k single-chip EPROM, the CMT tools associated with the CMT-71-P01 EPROM programmer were using a single checksum byte for the entire module:

Quote:PTGENC$
Generates the proper checksum for the port and places
it in the last byte in the port's address space. The
hex value returned is the byte written to that location.
This function also chains all files that require
chaining, before generating the checksum.

Of course, it was possible NOT to use PTGENC$ and rely on ROMCOPY or EPRMCPY instead for the checksum byte(s).

J-F