I'd suggest this as a good question for the next pub quiz.

"What popular computing device has been manufactured and sold by a major IT manufacturer continuously for the past 26 years, is still considered 'best in class', and is so strong that it was once eaten by a hippopotamus in a zoo and was recovered from her droppings, washed and found still to be functioning?"

Of course, every geek will know the answer. It is the HP12C calculator, beloved by businessmen and accountants.

The most famous HP-12C of all was being used by a zookeeper to calculate exact feed mixtures. The zookeeper accidentally dropped the calculator, and one of the hippopotami in his charge consumed it. The calculator survived the hippo's digestive process as well as the washing that followed. These devices were built to last.

The popularity of the HP12C shows no sign of dying out. They are still for sale in the big office-stationery catalogues. They are certified for use in the CFP and CFA certification exam. It looks, and is, a period piece. It has a one-line LCD display and Reverse-Polish Notation data entry. However, it is just a keystroke to calculate loan payments, interest rates and conversions, standard deviation, linear regression, percent, TVM, NPV, IRR, date arithmetic, cash flows etc. It was developed from a long line of electronic business calculators and it is hard to see how it can be improved.

The HP16C has the same robust design, designed for programmers and computer scientists. Unfortunately it is no longer manufactured but you can enjoy windows-based simulators. In fact I bought my HP16C in 1984, I think, and it proved to be invaluable. I still have it and it works as well as it always did. You can set it to the same word size as the chip you were programming for, the overflow and carry behaviour. It would do Integer and floating-point math; it would do all the shifts and Rotate functions, masking, multiply/divide, bitwise Logic, bit setting and testing, Flag setting and testing and so on. To cap it all, it was programmable.

This calculator has nestled into my shirt-pocket for so long that I sometimes fancy that part of my soul has entered that calculator, and part of that machine intelligence has, in turn, entered my brain. Certainly, I programmed in Z80 and 8086 assembler for so long that I could once run my eye down several pages of code and know what would be in the various registers of any CPU that executed the code at the end of it. I still have it here on my desk as I type this in, solid, chunky and utterly reliable.