HP21S Impressions  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: HP21S Impressions (/thread95677.html) 
HP21S Impressions  Juan J  07082006 Hello, After much looking I finally got an HP21S, made in the US in 1989. A nice machine. After some reasearch I found it is very similar to the HP20S, at least in operation and programming. I also found out that user's manuals are hard to come by, apparently because this model was handed out to classrooms in lots with one manual for each. Offtheshelf models with box and manual were also available but are much more rare. No manual came with my 21S. I have figured out most of the functions but I have found myself wondering about these stories of many calculators being distributed to classrooms with just one manual. Are they true?
Re: HP21S Impressions  Raymond Del Tondo  07082006 Hi,
at some time there was a site which had a pdf version online for a while.
Raymond
Re: HP21S Impressions  Juan J  07082006 Hello Raymond, Your register does not show an email address. Could you please contact me? Thanks in advance.
Juan
Re: HP21S Impressions  Karl Schneider  07082006 Juan  So, if those stories you've heard are correct, that would explain why the one I bought more than a year ago was without manual, and that I've never seen a manual or calculator with manual offered on eBay. The HP21S is kind of a "niche" model that  along with the HP20S and HP10B  is a lowend Pioneerseries characterized by the 7segment LCD readout. It does have some functions that are hard to find on other RPN or algebraic models.
A really capable Pioneerseries calculator for statistics would have utilized the highend Pioneer hardware and firmware (i.e., HP17B, HP17BII, HP27S):
This would allow sorting, minimum, maximum, median, and mode. It would also prevent errors that occur from calculation of standard deviation from summation quantities, rather than from mean and deviations.
For example, calculate the sample standard deviation of The correct answer is 1. However, on any RPNbased model or the HP20S or HP21S (which perform summations), an incorrect answer of 0 will be returned, due to roundoff error in the subtraction of summation quantities. The HP17B, HP17BII, HP27S and RPLbased models store the input data, calculate the mean and then the deviations. They give the correct answer. The HP21S, like the HP20S, has those builtin keystroke programs (using LOAD) that are not intuitive to use, then wipe out program memory when they are loaded. Not the best of ideas.
Edited: 8 July 2006, 4:00 p.m.
Re: HP21S Impressions  Walter B  07082006 Just want to add one point: The 21S is the *only* HP featuring 4 standard distributions (Gaussian, Student's, Chisquare and F) built in.
So it's unique in the line. I think it would be rated higher if it would have been a RPN model.
Re: HP21S Impressions  Neil  07082006 Hi Juan,
Here is the link to the Hp21s manual: Re: HP21S Impressions  Raymond Del Tondo  07082006 Hello Juan, my email address: magic48ges[at]gmx[dot]de Regards
Raymond
Re: HP21S Impressions  Raymond Del Tondo  07082006 Ooops,
just saw that Neil had the link handy:)
Raymond
Re: HP21S Impressions  Juan J  07082006 Hello,
Limitations notwithstanding, the only missing thing is RPN. It would be a greater machine if it had it but, well,it is algebraic. Once again, tanks to you all. Kind regards,
Re: HP21S Impressions  Palmer O. Hanson, Jr.  07082006 A question on "Statistics functionality that stores each datum":
I don't have a HP21 to play with but Viktor Toth's site tells me that the HP21S has only ten memories. Wouldn't that severely limit the capability of a statistics function that stores each datum?
Re: HP21S Impressions  Gene Wright  07092006 Correct Palmer. That's why he said "a really capable pioneer machine WOULD have..." He is saying that for a statistics machine like the 21S, it would have been really nice if they had made it listbased for statistics, like the HP17b, etc. The 21S does not do that and falls short in that regard.
Hope all is well. Re: HP21S Impressions  Palmer O. Hanson, Jr.  07092006 Designers and manufacturers make choices when they make a product. My impression is that the HP21 was intended to penetrate a low cost market. If so I suspect that cost drove the design and yielded a memory limitation.
You can go back and say "Wouldn't it have been nice if HP had made a really capable HP45 or HP80 with listbased statistics but those machines didn't have enough memory. Did the HP65 or HP67 come with list based statistics? I doubt it because again the memory limitations came into play. The same thing was also true with TI's SR52. When the TI59 came along the baseline machine with the Master Library module installed didn't provide listbased statistics but shortly after I had one I wrote such a program which mirrored the capability of the timeshare computer I was using even though the TI59 could handle only90 entries. The Statistics module of the TI59 did provide listbased statistics. I didn't find a listbased statistics capability in the baseline HP41 so I wrote one. I presume that one of their modules provided it.
Re: HP21S Impressions  Karl Schneider  07102006 Quote: Not an unreasonable statement, but I'd say that it misses my point. There were three levels of Pioneerseries calculators released in 198889:
It is clear that the three platforms had already been developed for other models. I'm saying that a really good "statistics specialist" model would have been based on the highend Pioneer platform, instead of the lowend one. Maybe such a product would not have served a significant "features and price" market niche, but, we'll never know.
Quote: I don't believe so. The HP41 STAT module included 4 kB of RPN keystroke routines, providing the missing regressionanalysis (curve fitting) capabilities for the HP41's builtin twovariable summation, but no listbased statistical programs that could consume considerable user RAM if utilized. A thoughtful listbased statistical program for the HP41 might create a data file in Extended Memory, then store input data directly to that file. Nearly 600 singlevariable values could be stored in that manner.  KS
Edited: 10 July 2006, 4:15 a.m.
