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The early history of HP calculators

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Re: The early history of HP calculators

#21

Post by acomjean »

pmoriarty wrote: post #9

I've never used an HP calculator, but I've recently been getting interested in emacs' calc, which is also RPN. Could someone who's used both talk a bit about how they compare? Are calc and emacs missing something that made HP great?

dc on the unix command line (linux too), is an rpn calculator. I use its non rpn counterpart bc. I've been told they aren't great (buggy), but for simple math they work fine.

I used a hp 32S in college, less mistakes make with rpn then entering calculations the other way. though newer calculator allow entering of whole equations ((10 *5)^2)/3 made this less useful.

The hand helds are more portable than emacs.

Re: The early history of HP calculators

#23

Post by siberianbear »

Wow, this is bringing up some memories of my childhood.

One of my childhood friends had a father who was a licensed surveyor and civil engineer. He showed me how to write programs one one of these calculators. I was fascinated with it, and started writing simple programs to do obscure calculations. After I showed him what I had figured out, he showed me how to remove the faceplate and access a special test mode by pushing some hidden buttons near the . key at the bottom.

In retrospect, I can't figure out how some civil engineer in a rural area knew how to access and use these test functions. Probably, he had a friend from the university who worked at HP or something.

I remember that these calculators use something called RPN (Reverse Polish Notation). To do "3+4" you enter 3 4 + . I had a university professor ask once, what's the opposite of RPN: when you enter "+ 3 4"? One other student answered "Reverse Italian notation?" And everyone in the class laughed so hard...

Re: The early history of HP calculators

#24

Post by MegaDeKay »

siberianbear wrote: post #23

Wow, this is bringing up some memories of my childhood. One of my childhood friends had a father who was a licensed surveyor and civil engineer. He showed me how to write programs one one of these calculators. I was fascinated with it, and started writing simple programs to do obscure calculations. After I showed him what I had figured out, he showed me how to remove the faceplate and access a special test mode by pu…

Actually, to do "3+4" you enter 3 4 +

That's it. Note that this is one keystroke less than the regular calculators used by mere mortals, and that is why RPN rules.

Source: my daily driver HP-15C that I've had since around 1985. Works perfectly and has only gone through two or three sets of batteries. I'd swear it was solar powered.

Re: The early history of HP calculators

#25

Post by mvaliente2001 »

agumonkey wrote: post #13
userbinator wrote: post #6

Notice the distinct lack of an '=' button --- HP's calculators have been almost exclusively RPN-based. It's funny to watch other (newer) developers reactions when they ask to borrow the calculator that's usually on my desk (a 42S) and then give it back several minutes later, with a puzzled look on their faces.

"you've been stacked" -- HP calc owner Last year I finally read the whole manual (as a teen I only used the symbolic differentiator, most useful and magical to my brain at the time). Since I learned about Lisp, so RPN programming features appealed to me. I realized that: 1) RPN has lambda > means (lambda (...) (+ 2 ...)) 2) RPN has a short syntax for them a 2 + >> Yes, 1990 HP RPN had arrow notation out of the box. T…

HP48(S(X)) also came with two excellent manuals with hundreds of pages of documentation. My only regret is that when I was in college, I could have written better programs. I tended to write huge functions with a deep stack, hard to understand, debug and modify. Had I know what I know now, I would have written dozen of small function and relying more in lambdas... And I didn't know I can use named arguments.

Re: The early history of HP calculators

#26

Post by agumonkey »

mvaliente2001 wrote: post #25
agumonkey wrote: post #13

Earlier quoted context omitted.

"you've been stacked" -- HP calc owner Last year I finally read the whole manual (as a teen I only used the symbolic differentiator, most useful and magical to my brain at the time). Since I learned about Lisp, so RPN programming features appealed to me. I realized that: 1) RPN has lambda > means (lambda (...) (+ 2 ...)) 2) RPN has a short syntax for them a 2 + >> Yes, 1990 HP RPN had arrow notation out of the box. T…

HP48(S(X)) also came with two excellent manuals with hundreds of pages of documentation. My only regret is that when I was in college, I could have written better programs. I tended to write huge functions with a deep stack, hard to understand, debug and modify. Had I know what I know now, I would have written dozen of small function and relying more in lambdas... And I didn't know I can use named arguments.

at least you did write them, I have respect for people suffering complexity when they don't know better

Re: The early history of HP calculators

#28

Post by zokier »

dm319 wrote: post #16

Getting good condition HP calculators can be quite expensive second hand. People interested in buying a new one should check out swissmicros [1]. They are bringing out an HP42s clone with quad precision decimal accuracy, which I'm looking forward to! [2] [1] http://www.swissmicros.com/ [2] https://www.youtube.com/watch?v=8LatjXPgLI8 EDIT: I don't have any involvement with swissmicros apart from anticipating their new…

One thing that has always befuddled me with HP calcs is their model numbers that don't seem to follow any rhyme or reason. How does the functionality of DM42 compare to for example WP34? And how does -48 compare, besides the relatively useless graphing capability? I see lots of people also preferring some other models (15, 16, 35, 41 etc), which I would have imagined to be strict subsets of these "juggernauts", but maybe that is not the case?

Re: The early history of HP calculators

#29

Post by waynecochran »

When I started college in 1985, every Physics student had an HP41C. You were at a distinct disadvantage on an exam if you had an infix calculator. I still have my HP41CX that my dad bought me in 1985.

Now I don't see any of the students using them. What happened? When I used to teach, I would write a large expression on the board and challenge students to a calculator duel -- me using my 1985 HP41CX and them using their lumbering infix calculator. I would always win.

The magic is the automatic saving of subexpressions on a stack. Once you got the hang of it, you would never want to go back to an infix calculator.

I have the HP41C app on my iPhone, but you miss the beautiful haptic feedback keys that the HP calc's had.

Actually, the very first programming course I ever took was a 2 credit course called "Programming Calculators" and we learned to program to the HP41. When a program was running, a little "bird" glyph would "fly" flom left to right across the LCD screen. I remember writing a program to get the bird to fly backwards. Silly, but fun.

Of course I had the Math Module that you could plug in and the magnet card reader. Anyway, I always wondered what happened in the intervening time that no one seems to use them anymore.

Re: The early history of HP calculators

#30

Post by nothotdog »

b5 wrote: post #4
jimnotgym wrote: post #3

I'm too young to remember, but it seems the UK calculator of choice was the Sinclair http://www.vintagecalculators.com/html/sinclair1.html

My dad, who went to Uni in the '70s to do maths and physics, has a Sinclair scientific that looks very similar except has blue LED digits. I don't know the exact model.

the bright blue LED had not been invented yet, it was probably vacuum flourescent

http://www.vintagecalculators.com/html/calculator_displays.h...

https://en.wikipedia.org/wiki/Light-emitting_diode#Blue_LED

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