The HP 48gx series of calculators have gained almost a cult following among geeks of all sorts. I know mine is always within arm's reach of my desk at home =:-) This being said, there are (as with anything) advantages and disadvantages to this line of calculators, and depending on your application, it may or may not be for you.
First, the disadvantages:
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It's slow. Compared to a TI-82 it takes maybe twice the time to do any given calculation. Most of the time this doesn't matter, but in the case of solving really hairy equations, plotting complicated equations, or anything like that it can end up mattering.
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It's heavy. They designed this thing to be dropped, stepped on, fall off your desk, and so on. The price you pay for it being so solidly built is that you carry the weight around (all 264 grams if you believe HP's spec sheet).
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For those who think of formulas only in normal infix notation, the postfix notation, or Reverse Polish Notation native to the 48g series is a little counterintuitive. It takes a while to get used to it. Any "Forth" programmers out there should rejoice though.
Now for the advantages:
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Flexibility:
- The calculator is in essence a small general purpose computer. You can program it in many languages, from it's native assembly language (or C if you want), to a fairly low level (and fairly fast) interpreted bytecode called System RPL, all the way up to a very warm and soft high level language, sort of similar to BASIC but stack based, called User RPL.
- There is a fairly powerful hierarchical file system with a fairly rich (although a little klunky) user interface and a decent API.
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There are many user configurable settings, and anything you can do with the UI, you can just as easily script for automation of common tasks and building new tools for your specific needs.
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Expandability:
- The HP 48gx has two expansion slots which can accomodate a variety of periperals (including disk drives) but are most commonly used to add additional RAM or to add additional software packs for application specific functions (surveying, various types of engineering, more advanced math functions).
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The system also comes with an IR port for talking to printers, computers, or other calculators. In addition there is a 9600bps RS-232 port for backups, data collection, modem usage, etc...
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Long battery life.
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Durability. (see the weight section under disadvantages).
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Wonderful reliability. The application software and the underlying operating system are all rock solid. Few to no crashes, graceful error handling, and most importantly, if something does go haywire, it's very easy to restore things to a known state and figure out what went wrong.
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Rich feature set:
- EquationWriter as it's called by HP is a neat mini-app that allows you to type in a normal old infix equation and see it as it would be typeset in a textbook or reference manual and edit the equation in that form, which can later be essentially compiled into a more native format for faster execution.
- An extensive library of commonly used formulas for architecture, physics, chemistry, electronics and several other fields.
- The HP 48g line of calculators supports unit calculation, so you can keep track of all your units as you calculate, and it will stop you from making incompatible calculations (for instance it won't let you add 3kg to 102.331 inches), and it'll convert for you if units are compatible. That ends up being really handy.
- Full featured and user extensible solving, graphing, and statistics capabilities.
So, if you've got the patience to wait for a slightly slower calculator, but you want durability, reliability, and a rich programming environment, this may be the system for you. I have to say that if my 48GX were to bite the dust, I'd buy another! But on the other hand, after somewhere around 8 years of faithful service, it's still going strong and showing no signs of weakness.