HP 41C calculator

You will.. They're not particularly rare (heck, if I can find them...) A lot!. Firstly the build quality is a lot better (the quality of HP calculators really went down when they came out with the clamshell models (18C, 28C, etc) and has kept on going down. Secondly they're very different machines. The HP48 series are good _calculators_. Everything you want is most likely built-in. And that's why I use my 48SX, 48GX and 49G for calculations... The 42S is, IMHO, a sick joke. It's a 41 with all the good stuff taken out. No expansion, no I/O apart from the IR printer output. No extended functions, none of the interesting stuff from the HP41 modules. OK, the Advantage ROM is sort-of there, but that's the 41 module I use the least. And you can't do synthetic programming on it [1]. The 41 is what I call a system calculator. On its own it's a nice machine, but it's not got that much. But you can add stuff to it. I've had my 41 talk to a disk drive, plotter, thinkjet printer, HPIB interface to a logic analyser and a data logger all at the same time. Try that with any other calculator (OK, the HP71 can do that too, of course...). There's a down side to this, though. You may not think you'll want all the add-ons, but you will. You'll spend many times the cost of the 41 on add-ons, and your little calculator will end up taking over your workbench. [1] Basically undocumented multi-byte user language instructions 'synthesised' by combining parts of other instructions. You can do things like treating the alpha (text) register as 3 or 4 more numeric registers, you can edit progam memory (or key assignments) from within a running program, etc, etc, etc. You don't need any extra hardware for this (unlike true machine code programming). -tony