brad wrote:By the way Garth, what HP handheld computers do you have? I have some of the old Psions from the early 1990's which are still great to use.
I remember the early Psions from the mid-1980's or so.
My HP handhelds are the HP-41cx and a couple of HP-71's. There are engineers
still introducing new hardware and module images for the 41, and someone has a prototype FRAMs for the 71 out now, with production expected soon. I still use the 41cx every day, as a calculator, and running programs I've had in there
continuously for 25 years without ever re-loading, plus keeping phone numbers, daytimer (to remind me of appointments), even my alarm clock. I have not used the 41 for controlling lab equipment in years, but the possibility is there to do so again at any time.
The 71 is more powerful than the 41, but not as practical as a calculator, so my 71's seldom get used. I did use the 71 for generating the huge look-up tables which are in Intel hex form in the
look-up tables section of my website. (The link goes to the front page of that section, describing how so much can be done in scaled-integer math including things people tend to think require floating point, and telling what's in the tables and how to use them on a 6502 or 65816 computer. In some cases, looking up answers can be
nearly a thousand times as fast as having to actually calculate them on an 8-bit computer with no math coprocessor, because every answer is there, pre-calculated, accurate to every last bit, so there's no interpolation involved.) Most tables are 16-bit and have 64K cells of two bytes each, or 128K per table. A few tables are other sizes.
For the 41cx, I have:
- Advantage module, which is for matrix and complex-number operations, base conversions, financial calculations, roots of equations, boolean operations, polynomial solutions & evaluations, integration, differential equations, vector operations, coordinate transformation, and curve fitting
- double module with HPIL (for interfacing to dozens of things at once) and
- Extended I/O;
- double extended memory module (for files)
- ZENROM which is for synthetic and assembly-language programming. Synthetic programming is basically user language but lets you into registers and places the designers didn't originally intend for the user to go, plus lets you do several things much more efficiently, like if you want to embed an escape sequence in a string, or directly key in characters that aren't on the keyboard. Various areas suddenly have a lot more options.
The 41cx is like a 41c with (all built in):
- main memory internally filled out
- time module (real time clock, stopwatch, time & calendar functions, alarms to interrupt and take control, even waking the machine up if an alarm came due while it was sleeping, etc.)
- Extended Functions
- text editor
- and a few other things you cannot get on the 41c or 41cv.
I also have:
- two digital HPIL microcassette drives which are smart like a disc drive and use a FAT, and look up files in the fat and very quickly spin out to the file
- HPIL-to-IEEE488 interface converter which I used when I was using the 41 to control a rack of lab equipment at work
- HPIL-to-parallel interface converter
- HPIL-to-RS232 interface converter
- card reader which works but I've never used it because I only got it for the shell and connector, in order to build something else into it, which I've never actually done
- bar-code reader which someone gave me recently in new condition, but I've never used that either. The neat thing about bar code, back in the day, was that when users' groups got together and you wanted to distribute programs, all you needed was a photocopier, and people could enter the program much faster than keying it in. Same thing with mailing someone a program, on paper, in an envelope, before the internet existed. (There were HPIL modems for direct connection without the internet, but they were more rare.) Photocopies were much cheaper than microcassettes and magnetic cards.
- HP92198 80-column video interface
- two HPIL printers, the miniature thermal one, and a Thinkjet that took standard-sized fanfold paper. Usually when I want to print something out though, I just go through an interface converter and use an Epson parallel printer.
Everything here can be used simultaneously. You don't have to remove one module or device to use another one.
A new hardware module I want to get is the
NoV-64 which has 64KB of flash, and I want to load in at least the new
41z module image which gives the 41 a true 4-level complex stack and over 100 complex-number functions, all written in assembly for maximum performance (much faster than the Advantage module's complex-number functions, and more complete); plus the new
Sandmath module image which has loads of math extensions; plus perhaps a couple more module images. I could put at least the ZENROM module image (4KB) in the NoV-64 to free up one of the four ports for it, if not also the Advantage ROM (12KB). There is now available the
41CL transplant logic board (see also
this .pdf and
this link) which makes the 41 up to 50 times as fast as the original, and also comes with over 200 modules built in; but it's pretty hard on battery life, and the stuff I do doesn't really require that much speed. I've been wanting to the the NoV-64 for some time, but every time I think I can justify the expense, my wife wants another upgrade to the house, or tax bill nearly wipes us out or something.
For my primary HP-71, I have the HPIL module (again for interfacing to loads of things at once), the Math module, the Forth & Assembler module, and 160KB of extra RAM. All the HPIL stuff mentioned above works with the 71 as well as the 41.
Here's a poor picture of the 41:
and one of the 71: