Not much information here. The HP42S is said to be from 1988, yet the back of the calculator says 1987. So which anniversary is it...the 22nd or 23rd?
Regardless, knowledgeable people acknowledge the HP42S as the finest RPN calculator ever made...22 years after introduction. What a shame that HP no longer has capability to produce a machine that comes close to what was available almost a quarter century ago. The HP32SII, HP33S, and HP35S are execrable.
RPL is powerful, but RPN is straight-forward, non-tricky, intuitive, and a system that people can use without great study. It's a pity that freshman computer science types held sway with RPL, causing HP's loss of use for the things for which people still use calculators.
The HP50G is orders of magnitude a better machine than the TI-89 Titanium (HW 4). It's a really great product. But it has lost to the TI junk because of RPL's idiotic difficulty of use. At the very least, the successor to the HP50G should provide for programming in either RPL or RPN.
But, I digress. The HP42S represents much better times. Happy anniversary, HP42S and the long gone talent of the HP folks who created you!
Edited: 31 Oct 2010, 6:20 p.m. after one or more responses were posted