HP Forums

Hi.

TI went from four steps to three for transfer instructions and from three strokes to two for memory instructions. What technology and memory chips would it have taken for 58/59 keycodes in the SR-52 to begin with?

It's essentially the same reasons the HP-65 wasn't as powerful as the HP-67, which wasn't as powerful as the HP-41, and so on.

The same chipset (TMC0501 etc.) Is used in the SR-52 and TI-58/59, but the SR-52 has only 3K (13-bit words) of ROM, vs. 6K in the TI 58/59. For the TI-58/59, there were the same number of ROM chips in the calculator, but by that time they could make 2.5K ROM chips, vs. only 1K when the SR-52 was designed, so it would have taken twice as many ROM chips, as well as delaying the introduction of the SR-52 by the time needed to write and debug twice as much code.

As Bill Wickes of HP famously observed some years later, "ROM wasn't built in a day."