Tuesday, 09 November, 2004

My First Programmable Anything

I got my first calculator in 1976 or 1977--a Casio castoff from my dad.  It was no great shakes, just your basic four-function calculator with a single memory.  Not that I really needed the thing.  None of the problems I had to solve up through trigonometry required the calculator.  We had trig and logarithm tables, slide rules, and knew how to interpolate.  Come to think of it, I'm not sure we were allowed to use electronic calculators during tests.

In the summer of 1978 I saved up enough money (and $80.00 was quite a lot to a 16 year old kid back then) from my part time furniture moving job to buy a Radio Shack EC-4000 programmable calculator, which was a re-branded TI-57.  What a fascinating piece of equipment!  I bought the thing a couple of days before my family headed out on a driving trip to Disneyland.  I spent the three traveling days curled up in a corner of the truck going through the book, learning how to program the thing.  I even spent a little time with it at the campground there by Disneyland.  By the time I'd had the thing for two weeks, I knew that I was going to be a computer programmer.

The TI-57 was kind of an odd beast in the world of programmable calculators in that it was relatively inexpensive but had branching instructions.  Other programmable calculators in its price range lacked branching instructions, which limited their usefulness quite a bit.  I remember that it took me a day or so to understand the usefulness of branching instructions, but once I did...wow!  I wrote all kinds of cool little programs for the thing, drawing flow charts and testing my logic like the manual taught me before painstakingly keying the instructions into the calculator and testing the program.  The only program I can remember well is my prime finder:  given a number, it would go through the calculations to tell you if it was prime.  I was quite impressed with myself when I reduced the time required to determine the primeness of the number 1,000,003 from 35 minutes to a little less than eight minutes.  Oh, the joys of program optimazation.

I just stumbled across the Datamath Calculator Museum today while I was looking for something else, and seeing that old calculator brought back lots of good memories.  The Web really is a wonderful thing.