It would appear I’ve been channeling the TI-59 after all. Searching online brought up the keyboard for the TI-58/59 calculators. It didn’t take much for me to realize I’d replicated the core keypad in pretty much the same order as the original calculators. I quickly added two more rows of buttons/keys, right beneath the top row, with their proper symbology, and pretty much replicated the primary core keys.

The only keys not on Alternative Calculator are the far left row (the fifth row) that are dedicated to keystroke programming, a hallmark of those calculators. A final row is missing across the very top as well, the keys A-E that were meant to start programs loaded into the calculator.

A final key, the 2nd key, is also on that far left fifth column. It enabled a 2nd function for every key on the calculator.

If I want to follow the path of the TI-59, how far to I want to follow it? Do I want full emulation, quirks, bugs, and all? Do I want to replicate all the design decisions?

As much as I liked the TI-59 I recognized it had it’s problems and limitations, which were the product of the technology of the times (mid- to late-1970s). For example, a number of calculators show every keystroke entered, including all the operators. This gives a complete visual indication of where you are in formula entry, which is powerful especially if you’re interrupted and then come back to what you were doing. I can’t count the number of times I had to start over on my old TI-59 because I was called away from using it, only to have to clear everything and start over when I came back to it after an interruption.

There’s also the concept of keystroke programmability. The TI-59 (along with the equivalent Hewlett Packard calculators) allowed you to enter arbitrary sequences of keystrokes that combined the built-in functionality of the calculator in new ways for solving complex mathematical problems. With the TI-59 you could save them off on small chewing-gum sized magnetic cards. I was so happy to have this capability in the late 1970s and early 1980s, but by the mid-1980s I’d completely stopped using it and had moved on. True personal computers were all the rage and the spread sheet was the power math tool.

How far do I really want to go with this? I started down this path because I wanted a better way to perform math on my Nexus 7 tablet. How much time and effort do I want to sink into this? This project now has all the makings of a detour time sink with little to no real return. I have a lot to think about…