Date addition: can it be done in a single HP 65 program card?

[Dave Britten]

(01-02-2020 04:27 PM)Don Shepherd Wrote:  

(01-02-2020 03:43 PM)Dave Britten Wrote:  Can the 65 safely record on both "sides" of a card, or do the tracks end up overlapping? I could fit it on a single card that way.

Never tried that! Do it and see if it works. That would be good to know.

I know the 67/97 was designed to do that, and I've seen plenty of pictures of cards with both write-protect notches cut out, but I don't know if the 65 reader/writer has the heads aligned to only write on half the card. I'll have to play around with one of my blanks and see if it works (or read through scans of 65 Notes and see what others had to say about it).

I played around with the Finance Pac date program some more, and the day numbering scheme seems to be set up so that Jan. 1, 0000 = 1. If I can work out a reverse calculation to convert back to a date, then I can just make a companion card that you load and run after pressing D and adding/subtracting days.