The Museum of HP Calculators

HP Forum Archive 15

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hp 42s
Message #1 Posted by e.young on 20 Feb 2006, 4:12 p.m.

I have never had the pleasure of using an HP 42s, but it seems to be highly prized by its fans. I just noticed one on ebay that is currently at $305 with 6 days left. From the item description it is essentially unused. What is the appeal with the 42s that it consistently goes for such high dollar amounts on ebay?

Re: hp 42S [Overview]
Message #2 Posted by Karl Schneider on 20 Feb 2006, 4:41 p.m.,
in response to message #1 by e.young

The HP-42S is the most advanced scientific RPN-based calculator that HP produced. Its programming paradigm is shared with the HP-41; it carries over the applicable computational functionality from the 41, but adds MUCH more: complex-number functionality, real- and complex-matrix operations, rootfinding (SOLVE) and numerical integration, as well as hyperbolics. It has 7 kB of RAM, but its firmware will support 32 kB.

It shares the high-res two-line dot-matrix display and IR-printer transmitter with the HP-17B/17BII and HP-27S, but lacks the algebraic equation solver and the clock/time-calculation/alarm functions of those models.

The main criticism of the 42S is that it lacks the I/O and expandability of the 41. In that sense, it was not a fully-adequate replacement. The HP-48SX provided those things, but it was RPL-based -- incompatible with the 41.

In defense of the 42S, its trim-line Pioneer-series package and low-capacity button-cell battery effectively precluded hard-wire I/O and plug-in expandability. If only the 48 had been RPN-based...

I bought my early-version 42S on eBay in 2002 from a somewhat-disgruntled former HP employee. Even then, units in good condition were going for US$200.

Of course, more about the 42S is available on the MoHPC main page.


-- KS

Edited: 22 Feb 2006, 10:39 p.m.

Re: hp 42s
Message #3 Posted by Thomas Okken on 20 Feb 2006, 5:33 p.m.,
in response to message #1 by e.young

In a nutshell, the 42S is the most powerful RPN scientific ever made.

People like it because it has the same easy-to-learn four-level RPN and keystroke programming model as the HP-41 series... But the 42S pushes that model much further, by adding named variables, complex numbers and matrices that can be manipulated on the stack just like plain real numbers; and it has HP's excellent numeric SOLVE and INTEG applications built in as well. It's perfect for quick-and-dirty programming, and supports even medium-sized applications. And, finally, while it has way too many functions to put on the keyboard, so they had to be hidden away in menus, those menus are much better done than those on any other HP model.

- Thomas

Re: hp 42s
Message #4 Posted by Walter B on 20 Feb 2006, 7:41 p.m.,
in response to message #1 by e.young

It's the only RPN HP calculator I know allowing you to enter keystroke programs just without any need to care for program space - there will be sufficient space always (for quick-and-dirty programs)!

As mentioned already, it's the RPN model with the highest calculating power. It provides some hundreds of functions. At the same time it has a *very* clean keyboard. If it would feature a better display and a comfortable way of data exchange with PCs, it could compete today still easily. Impressive device!

But alas, this WAS the top model ... so try to get one. IMHO they are particularly expensive in the USA. I got mine for < 130 US$ at eBay two years ago.

Good luck - Walter

Edited: 20 Feb 2006, 7:44 p.m.

Re: hp 42s
Message #5 Posted by Valentin Albillo on 21 Feb 2006, 4:40 a.m.,
in response to message #1 by e.young

Hi, e.young:

The HP42S is a truly wonderful machine, signaling the exact path RPN calcs should have taken. May I suggest you have a look at this article of mine, Long Live the HP42S !, which is a 14-page PDF document fully describing and discussing the most important HP42S capabilities and outstanding features, plus it includes a large, non-trivial program, which is then thoroughly discussed, pinpointing the special techniques used.

This will surely help give you a clear example of what the machine can do and its powerful programming style.

Best regards from V.

Re: hp 42s
Message #6 Posted by e.young on 21 Feb 2006, 8:38 a.m.,
in response to message #5 by Valentin Albillo

Thanks to all for your responses.

Most of my experience is with the 11c and 32sII which I did not use for programming, being content with the beauty of RPN. It is actually the 33s that has opened my eyes to the potential of keystroke RPN programming because it has the memory capacity to have more that 2 programs entered into it. From your replies and researching the 42s on MoHPC I wish I could get my hands on one. The prices that it goes for on ebay are a little to high for me though. Actually, the hard part would be convincing my wife about the need to get another HP since I have already obtained several other HP's on ebay.

Re: hp 42s
Message #7 Posted by Howard Owen on 21 Feb 2006, 6:47 p.m.,
in response to message #6 by e.young

If you have an HP48GX, HrastProgrammer has his HP-42X emulator, which is a binary code simulator of the 42S. The simulation will also run on a 49g or 49g+, with some variation in capability. There are also a pair of very good 42S simulators that run on the PC platform. Christoph Geisslink's EMU42 is a binary code simulator, for which you must supply the ROM. This generally means you need to have a 42S before you can run EMU42. Thomas Okken's Free42, on the other hand, is a reimplementation of the 42S in portable C++. That means that a) you don't need a ROM to run it, and b) you don't need Windows either. Free42 will run on Linux and PalmOS, for example.

Hope this helps.


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