HP-71 Compu-LS module

[Dave Frederickson]

(03-20-2017 05:36 PM)rprosperi Wrote:  It converts OK, but it does fail the checksum verified by TITANCHK, however that could be due to the EPROM vendor not setting the checksum properly, which was quite common.

The reason the images fails the ROM checksum test, Titanchk, is because it's not a ROM. The Diagnostic ROM only checks checksums for ROM's. In the post, above, I've converted the IRAM to a ROM by removing the IRAM ID and inserting the proper checksums. Now figure out how I calculated the checksums.

For an example of a ROM gone wrong, examine the Finance ROM and you'll discover that it contains the IRAM ID. Apparently HP forgot to convert it to ROM.

Dave