UTILITY TO BUILD SYSTEM LOAD DECKS AND CART
I discovered that the checksum logic includes a card sequence number in the calculation, something I hadn't included. That caused my decks to be rejected with checksum errors. I modified my code and ran again, until my decks passed muster for checksums.
The next problem I faced was some error that the system loader found in my cards, yielding the highly informative error E02 INVALID RECORD OR BLANK. Since I had no blanks in the deck, it was one of the 39 card images for the phase I was trying to reload. I successfully passed the checksums but now had something awry in my formatting,
As I corrected each issue, I found myself in more subtle difficulties, meaning I was getting very close to passing all the tests in the loader program. The larger question is whether an error free run would generate the exact clone of the data I used as the pattern. I kept at it. The last problem was an incorrect end card minus one, which appears to need to be one word long. There was a simple fix to my program to handle this.
Something is still not right with the last data card, which I will look into further tomorrow.