OK, kids, gather round old Gramps as he shows off the first calculator he ever owned. He got it as a present for passing his O-levels. (Actually, even if I’d had the calculator prior to taking my O-levels, I wouldn’t have been allowed to use it for the exams. Unlike math tests today, It was slide rules only in those days.) Are you gathered round? Here it is, the Litton Royal Digital 5-T from 1973.
Just look at that beauty. It takes 4 AA batteries which last, oh, at least an hour. Fully loaded with those double-As, it weighs 9.9 oz (280g) – for comparison, an iPhone 4 weighs 4.9 oz (137g), half the weight. Dimensions? Glad you asked: 5.8" × 3.5" × 1.4" (or, for those of a metric persuasion, 147mm × 89mm × 36mm). This is one big-ass calculator.
If you look carefully you can see that it has light-emitting diodes (LEDs) for the 8-digit display, although Litton preferred to call them “Digitron Tubes”. They are the reason the batteries didn’t last. Well, that and the fact there was no auto-shutoff. If you forgot to turn the calculator off manually, the next time you used it you’d have to put in new batteries.
Another thing: there is no zero suppression for the display. Clear the calculator (the C key) and the display shows
00000000. Suppose you wanted to know what 355/113 was. Type in the 355, you’ll see
00000355. Hit the ÷ key, the display shows
355.00000. Type in 113 and you’ll see
00000113. Press equals to see what the image above shows:
3.1415929. I mean, those zeros just ooze accuracy, no?
And that K key is, er, key. It allows you to do a set of calculations with a constant. K for konstant, amirite? Let’s say I had those measurements in inches from above and I wanted to calculate the equivalents in millimeters. Since there are 25.4mm per inch, all I have to do (actually “had to do” since I used the calculator itself for this) is type
K to set up the constant calculation, and then
= to calculate the millimeter equivalents. Just try and do that with your fancy-schmancy Casio.
Despite its drawbacks, I loved that calculator. Using it was like magic; a feeling I have a hard time experiencing with any other calculator. When I first got it, I’d have fun just doing calculations. I’d compare its accuracy with my slide rule. I don’t think I’ve ever got over the sheer amazement of it working and how it could be right, time after time. By the end of the 70s, I had my degree and was earning coin as a programmer and that initial sense of wonder had gone.
Swing Out Sister - Blue Mood
(from It's Better to Travel)