67 Mag card with both program and data

[Dave Britten]

(06-02-2022 02:25 PM)tangdfx Wrote:  Hi，Tony

Is it possible that the program and data save on the same card side.

If it is not possible on the original hp67，is it possible on your HP67C ？

Thank you.

Not on the original 67/97. One card side holds either program steps or register data.

The TI-59 has a slightly dumber/more flexible approach to memory and cards. The calculator has 960 bytes of RAM divided up between program steps and storage registers (by default, 480 program steps and 60 registers, or a 50/50 split). You can allocate between 0 and 100 storage registers in increments of 10 (80 bytes), with the rest being treated as program memory.

Each side of a card holds 240 bytes (30 registers), or 25% of the calculator's memory. Thus there are four notional "banks" in memory, and two cards written on both sides can hold the complete memory of the calculator. Any one of those four banks can be written to the side of a card, by entering 1-4 into the display, pressing 2nd Write, and feeding in a card. That card side will be tagged with the bank number, and will be automatically read back into the correct bank (unless manually overridden).

If you've configured the calculator with a number of registers other than a multiple of 30, then you can potentially write a bank containing a combination of program steps and registers onto one card side. As far as the TI-59 is concerned, it's just reading raw bytes from the card into memory - how they are subsequently interpreted depends on how the memory has been partitioned.

The 59 card reader being "dumb" does offer one trick that I use often: after you write a program card, you can manually read it back into bank 4 (top of memory, where storage registers 0-29 live) by entering -4 into the display and feeding in the card. This will verify the card can be read without erasing the program steps in the lower banks of memory.