A(nother) Little Gem


As some of you with long memories may recall I'm something of a fan of the SPICE series, having owned several and extolled their virtues here before.

However I recently got lucky (auction) and managed to obtain my second WOODSTOCK machine. It is only a very basic HP21 model however it was in good condition and still works reliably. As with my HP25 I've been very impressed by the feel of the of it and even the keyboard layout - to quote a well known UK advertising slogan 'it does exactly what it says on the tin', no more, no less. I've been using it for the last couple of days at work, preparing some pricing figures, and I have to admit that I may be becoming a bit of a fan of the WOODSTOCK series. This little gem may just have found a place in my briefcase for a while, as it is time my HP33C had a bit of a rest.

Given the recent interesting discussions on this forum about the pros and cons of different keyboard layouts and form factors, I can't help but wonder if there there is something to be learnt from the designs of these older machines. Each was aimed at a specific type of user and if the HP21 and HP25 are anything to judge by they were very well thought out indeed. Interestingly I've found that while they are excellent hand-held machines (actually being that little bit smaller than the later SPICE series), they don't compare so well against later models when used on a desktop...

Perhaps this just emphasises how closely form has to follow function for things to 'just feel right'.

Mike T.


I used both the HP-21 and 25 for 25 years as a physicist teaching intro physics. I don't know what else I would have wanted in a calculator, for my purposes. They were very dependable, needing only a new set of rechargeable batteries about every 6 or 7 years, and always there for me.

Over the years, I saw adds for the Spice models, the Voyagers, the HP-41, (as well as the TIs), but never saw any reason to retire my Woodstocks. However, more recently, after retiring, I've become a collector, and now find I grab an HP-11C or 15C when I have a calculation to do.



Hi Mike...
Couldn't agree with you more about Woodstocks. I've had my 29C since it was new (in 1977), it's still going strong, and is still my favorite. IMO, the reason they just feel right is not only the nice compact size and optimal shape, but also the seamless, bathtub case...no clamshell seam to shift, creak and otherwise cause problems. I wish HP had built them all that way.
You're right about desktop use...they are a bit awkward. The LED array is on the same plane as the keyboard, so you have to be at a pretty steep angle to view it. Maybe some sort of an inclined pedestal would help.

Best regards, Hal



you're right! I had the same feelings when I worked with my 25C since 1977. It was a perfect handheld at this time for me (another young physicist then - hi Larry :) ). Everything I really needed in a cute, neat, powerful, rugged, reliable, small package.

The only feature I missed was linear regression. It was almost permanently residing in my program memory but consumed nearly all of its 49 steps, so I changed to a 11C in 1982.

Form-factor-wise, I still *love* the Woodstock design. Next to perfection for the functionality it contains! For today, however, "only" 30 keys and the small display space are very hard constraints. While one may make good use of the keys (at least it may be worth a try, though I guess it will be a hard one), IMO the display area *must* be expanded to meet today's requirements and expectations.

Nevertheless, a LCD-equipped Woodstock may still be the best choice for scientificly simple, "quick & dirty" calculations on the fly. AFAIK, Eric Smith works on such a machine.

For the time being, enjoy!


I used a 21 while working as a summer student doing field chemistry in the oil patch back in the early 80's. The form factor was a thing of beauty, as you could hold it easily and confortably in your left hand.

The only thing that I found frustrating was the LED brightness in the daylight out of doors. I made a shade out of cardboard and taped it to the calc. Low tech, meet hi tech!

Missed the linear regression yes, but back then I had time (and eyesight) to actually make a graph and determine the equation manually.

Loved the 21 and still have a soft spot for it. Can't really see the red LED's though without my specs though...

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