Finally discovered something a TI-30 can do that an RPN calculator can't

[Jim Horn]

OK, I confess. The reason for the AOS '67 program was two fold. First, the algorithm to parse and execute a general infix notation was part of a programming course I took in 1972 (!) and I wanted to see if it was possible to squeeze that into the HP-67's 224 steps. Also, in those days the level of energy shown by proponents of HP's RPN versus TI's AOS was almost comical. So having the HP-67 be able to do both (which the TI machines at the time could not do) was something of a lark.

Of course, on the actual 10 program instructions per second speed of the HP-67, using this program was an exercise in massive patience as there was a serious delay in everything it did. Today's simulators and even the HP-41's greater speed help a lot in that regard!

So, the program wasn't written as a serious tool for practical use as an infix notation calculator. But it does illustrate some of the tricks we all had to use back then to wring every bit of performance we could out of the limited resources we had back then.

Regarding speed - the fastest factoring program ever written for the HP-67 took about 165 minutes to test 9999999967, the largest integer prime it could handle. My HP 50g verifies that it is prime in under 1 second, a roughly 10000 times improvement. And the HP Prime is reportedly much faster still. "Good old days" my foot!