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Hewlett Packard's Cult Calculator Turns 30 318

Hugh Pickens writes "The Wall Street Journal reports that Hewlett Packard's HP-12C financial calculator has remained outwardly unchanged since its introduction in 1981. 'Once you learned it on the 12C, there was no need to change,' says David Carter, chief investment officer of New York wealth-management firm Lenox Advisors, who has owned his 12C for 22 years and still keeps it on his desk. 'It's not like the math was changing.' The 12C, which costs $70 on HP's website, is HP's best-selling calculator of all time, though the company won't reveal how many units it has sold over the years. The 12C still uses an unconventional mathematical notation called 'Reverse Polish Notation,' which eschews parentheses and equal signs in an effort to run long calculations more efficiently."
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Hewlett Packard's Cult Calculator Turns 30

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  • Unconventional? (Score:5, Interesting)

    by Frosty Piss ( 770223 ) * on Thursday May 05, 2011 @05:47PM (#36041672)

    The 12C still uses an unconventional mathematical notation called 'Reverse Polish Notation,'

    I still use the HP-41CV I bought new, made in Corvallis, Oregon ($400 or so at the time, with a card reader). Iâ(TM)ve never been able to do any significant math on a calculator that did not use RPN.

    At least in the courses I took, most people preferred RPN.

    • Re: (Score:2, Interesting)

      If you have to write any embedded assembly, thinking in RPN is more conventional than not.
      • Re: (Score:2, Informative)

        by Anonymous Coward

        I thought those RPN folks were crazy until I had to write my own stack-based RPN calculator for a school assignment. There is nothing more awesome than being able to compute a quadratic formula without using grouping symbols.

        • Re: (Score:2, Insightful)

          by Anonymous Coward

          There is nothing more awesome than being able to compute a quadratic formula without using grouping symbols.

          Sex is more awesome.

      • Re: (Score:3, Informative)

        by rubycodez ( 864176 )
        I would imagine FORTH coders and compiler writers would like it too
      • Exactly, which is why RPN was such a Jedi masterpiece of hand-waving.

        Problem: You're writing an expression evaluator on an early calculator engine with a really small stack, and/or you're too lazy to code an expression evaluator that understands order-of-operation conventions.

        Solution: make the user do the recursive-descent grunt work.

        Field goal: pitch this bit of engineering laziness as a feature, and watch people start a cult around it.

        My hat's off to HP for this one. That marketing guy/gal must've gone

    • by djl4570 ( 801529 )
      I used RPN in the first grade but we didn't call it that. I'd write down the first number, then write down the second number then add or subtract them. I have never understood why the vast throngs think RPN is unconventional. So called algebraic calculators are hybrid notation. If they were truly algebraic you would enter cos(n)= instead of n, cos which is postfix notation.
    • by wbean ( 222522 )
      Me too - except mine's a 41c. I used it to check a set of printed financial tables that we were publishing at the time, and to navigate a small boat across the Atlantic (pre GPS). It's still going strong after what must be at least 30 years. Sadly my HP-80 died. That must have gone back to about 1972.
    • I never had one. I never used TI either. I find both a bit painful to use myself. Instead I had (in high school/college) a Sharp EL-5100 "equation writer". Type in your equation, then press equal. If you make a mistake or typo you can edit it before pressing equal. Most other calculators require you to start over if the key you pressed 20 keys ago was wrong.

      Of course, the HP-41 series that so many geeky young pre-engineers wanted were extremely expensive. Budget plays a big part in choosing a good sc

  • My first real calculator was the HP11c, although I got it in '84 or '85, not '81.
    • Yeah, well, mine was an HP-45, which I still have. The batteries are long since dead, but it still runs fine off of wall current.

      Oh, and if you could see your way to getting off my lawn, I'd appreciate it.

  • by Tamran ( 1424955 ) on Thursday May 05, 2011 @05:54PM (#36041746)

    This is the scientific version of the same calculator, complete with RPN, a stack, plotting functions, matrix functions. I've had mine since 1991. It's a shame they tried to replace it with one that is crap.


    • Mine still has notes and cheats in memory from a dozen years back. I use it every morning as an alarm now, with ocasional simple calculation.
      • I managed to program two parts of Bach's Fugue in C minor using the "[FREQ in Hz] [ DURATION in sec] BEEP" command and could, if I borrowed another student's 48, transfer part 2 via IR and run both mostly in sync through out the entire piece. Two devices beeping in lovely counterpoint oblivious to the unintended awesomeness they accomplished.
    • by Sponge Bath ( 413667 ) on Thursday May 05, 2011 @06:29PM (#36042108)
      The 15C is the scientific version of the 12C. Same case, same button layout, same display. I cherish my 15C, but usually use my HP50g.
      • My 15c is always on the desk within easy reach. After 26 glorious years it is still going strong, still flummoxes my wife, and remains dear to my heart.
        • I always wanted the 15C. A guy in my Physics class had one. When I offered to buy it from him, he said initially yes, but then he became attached to it because I told him it was a piece of art.

          IIRC, its numerics algorithms were designed, at least in part, by renowned numerical analyst/expert Prof. William Kahan.

    • I've had mine since 93. Still works and I still used it as my main calculator up until a little over 18 months ago when I downloaded the m48 app for my iPhone. I use it with the iPhone calc skin, but it still gives me a mock up of the HP48 screen, still used RPN, and since I used basic math most of the time works wonders for quick calculations.

      The best part is when I give it to friends and they try to add 1+1 by typing One, Plus, One and get an error instead of 1 enter, 1 enter, +

  • you would think (Score:5, Informative)

    by jbolden ( 176878 ) on Thursday May 05, 2011 @05:55PM (#36041758) Homepage

    You would think given that calculators still sell pretty well and this one is doing good for 30 full years that HP would maybe consider that they made a mistake in essentially killing off this line. Wouldn't it be wonderful it HP put out hand device for engineers as far advanced a the HPs were then?

    Anyway the scientific version of the 12c is the 15c: []
    And my love was the 28S. []

    • Whoa. I've had a HP-15C for 20 years. I never realized it was so kick-ass. I wish I knew how to use it properly.

      • by jbolden ( 176878 )

        If only 20 years you got it as a hand me down. By the time you got it, it probably wasn't worth it. The 15C is nowhere near the 48's which is what was current then.

  • by davidbrit2 ( 775091 ) on Thursday May 05, 2011 @05:56PM (#36041760) Homepage
    Now bring back one of the models the scientists/engineers will care about, like the 15C or 42S.
    • Now bring back one of the models the scientists/engineers will care about, like the 15C or 42S.

      Actually, it makes more sense to do what they did - bring them back as smartphone apps [].

      • Now bring back one of the models the scientists/engineers will care about, like the 15C or 42S.

        Actually, it makes more sense to do what they did - bring them back as smartphone apps [].

        I may be biased but I think it makes more sense to put the functionality of various traditional handheld calculators into a single app. Perpenso Calc for iPhone [] optionally supports RPN and offers scientific, statistics, business, hex and bill functionality. More importantly you have the option to use a modern worksheet format for the time value of money, cash flow, amortization, break even, and profit margin calculations; or use the traditional button based approach if you prefer.

    • Just grab droid48 [], an HP48 emulator. I was scouring ebay looking for a replacement for my trusty HP15C, until I found this and installed it on my phone. I still think the 15C looks cooler, but the 48 does everything I need.
    • Yay for the 42S. I never really grokked RPN before I got the 42S with it's two rows of output - 20yrs ago in my first year of engineering. Once I could see (and more easily track mentally) the two values the operator was going to work on and how they popped off the stack, it all instantly fell into place and made perfect sense.

      They had awesome manuals too. I remember writing a program for figuring out 2nd moments of intertia and centroids of composite shapes where you entered a sequence of dimensions for th

  • by NiceGeek ( 126629 ) on Thursday May 05, 2011 @05:58PM (#36041782)

    If you find one in the wild, and don't have a personal use for it, Ebay it. Those things are worth their weight in gold. Sold one for almost $200.

    • Re:15c (Score:5, Funny)

      by hawguy ( 1600213 ) on Thursday May 05, 2011 @06:07PM (#36041886)

      If you find one in the wild, and don't have a personal use for it, Ebay it. Those things are worth their weight in gold. Sold one for almost $200.

      You got ripped off - gold is around $1475/ounce, your 4 ounce calculator should be worth around $6000.

  • My grandpa had an RPN calculator made by Novus. I don't remember which model but it came out in the mid-70s. I remember playing with it when I was a kid. CSB

    • I still have a slide rule that I used for my Maths "O" level in 1976, to check my answers. Now get off my lawn.
      • by h4rr4r ( 612664 )

        Slide rule? Luxury! We had to share an abacus for the whole class. It only had 3 beads.

      • Re: (Score:2, Flamebait)

        by superwiz ( 655733 )
        i don't trust anyone who claims to know any math and spells it "maths"
        • You don't trust anyone who isn't American?

          Actually that kinda makes sense now that I've said it out loud...

  • RPN is not a notation. It's a straightforward implementation of stack-based expression evaluation.

    In RPN (restricted to binary operators) any sequence is valid where at each binop the number of preceding operands is greater than the number of operators.

    R = v1 v2 binop1 v3 binop2 v4 binop3;
    R = v1 v2 binop1 v3 v4 binop2 binop3; ...
    R = v1 v2 v3 v4 binop1 binop2 binop3;

    In linear notation, without parentheses, your ordering options are limited:

    R = v1 binop1 v2 binop2 v3 binop3 v4;

    Linear order implies structure

  • the reason rpn gives the shortest way to write expressions is that there is a natural 1-1 mapping between a stack and a tree. and since people try to organize most knowledge into trees (until they run into insolvable groups), the most compact way of representing trees will win as a method of representing most operations.
  • My foot it is. All depends on what career you are in if its 'unconventional' or not.

    Strange thing is these cost as much as they did when i bought mine 20 + years ago.. They should be cheaper now, so what is up with that?

    • Strange thing is these cost as much as they did when i bought mine 20 + years ago.. They should be cheaper now, so what is up with that?

      If you figure $61 based on a google search [], and calculate the inflation-adjusted price [] then you see that it's only actually $35.71 in 1990 dollars. So they have become significantly cheaper.

  • by sjbe ( 173966 ) on Thursday May 05, 2011 @06:30PM (#36042112)

    Look at any business school class these days any you will not find very many HP-12Cs or TI BA-IIPlus calculators anywhere. Most serious number crunching is done on a spreadsheet so the only use for one is if you are in a meeting or need to do a very quick calculation when a computer isn't readily available. (happens now and then) The HP-12C is a fine piece of equipment but if you have a spreadsheet available it's kind of like using a slide rule. Sure it works but it probably isn't the best tool available most of the time.

    I'm actually a certified accountant. I have one of the TI BA-IIPlus calculators and the only time I have used it in the last 8 years was to take a certification exam. (they only allow those two calculators in the test) Otherwise it sits in a drawer and gathers dust. Frankly I can't imagine I'm going to use it in the next 8 years either. For reasons I cannot fully grasp a lot of accountants still insist on using paper tape calculators to add up long strings of numbers even though they have a spreadsheet available on their computer. I can't begin to count the number of times I've seen accountants repeatedly type in long strings of numbers because of typos. Strange people who aren't willing to change with the times. I'm waiting for one to ask for the "4:30 autogyro to Siam [] one of these days.

    • Well it sounds like they just need an HP-200LX then, since it comes with Lotus 123 release 2.4 built right in.
    • The HP-12C is superior to Excel when it comes to performing quick financial calculations. The RPN allows you to enter in formulas without worrying about matching parenthesis and formatting the cells, while it contains all the essential formulas you need with none of the bloat.

      You can't hack numbers together as fast and efficient with any other calculator or computer program out there, which is why the HP-12C is still popular after all these years.

    • Most serious number crunching is done on a spreadsheet...

      You, sir or madam, owe me a new monitor and beverage. Although the sad thing is that I believe you...

  • It may have been designed for financial calculations, but it holds its own for science and engineering tasks, too. A lot of problems in a lot of fields lend themselves very naturally to RPN workflows.

    I learned to use these from my dad - he still has his, and I'm not sure there is any so-called feature that could ever make him give it up. Even when I was required to have a TI graphing calculator for classes, I found myself using it in RPN-style due to having learned to use the old HP (the last result is st

    • I don't understand how engineers could still use calculators today, except maybe out in the field where laptops are completely unpractical. I entirely stopped using calculators 15 years ago or so. I also never understood how supposedly tech-savvy people use calculator programs for PCs (like calc.exe or more "advanced" equivalents -- a totally superfluous software category IMHO). These days you can just fire up Python or Ruby (or, if you really must, Mathematica) and perform all kinds of interactive calculat
      • Re: (Score:2, Insightful)

        by Anonymous Coward
        Because sometimes you just want to pull out a simple tool, punch in a few numbers, and get an answer instead of waiting for an application to load, remembering the exact syntax the app wants, and THEN getting around to the actual inputting of the numbers.
      • by jbolden ( 176878 )

        I still pretty regularly use Pcalc. I also use the command line "e" for that sort of mini calculation. If I want to step up GHCI is pretty awesome.

    • by syousef ( 465911 )

      I've never met an app that felt as natural for handling pure computational tasks, and I have never needed to place a call from my calculator. Sometimes, purpose-built hardware is just better.

      It's called a spreadsheet. Repeatable. Entered formulae can be reviewed for errors or modified at will. Graphs are limited but good for what they do. Sorry no calculus, imaginary numbers, matrix algebra or other specialised or advanced math. Now I won't deny that spreadsheet use from a phone sucks, but I'm surprised so many people still cling to their old gadgets when there are infinitely better solutions.

  • HP made great calcs before the 12C. I had a 32E, my oldest brother had a 45, and my other brother had a 21. Now git before I break out one of my slide rules (straight or circular)
  • by Bloodwine77 ( 913355 ) on Thursday May 05, 2011 @06:41PM (#36042270)
    She gutted HP calculator R&D. The HP49G was the last new calculator they designed, I believe, and that was approximately 10 years ago. I still have my trusty, old HP48GX. I don't have a chance to use it much these days, but it is resting at a place of honor in my home office. HP made excellent calculators over the decades and it is a shame that a short-sighted CEO ended that legacy.
    • She gutted HP.

    • There was some design work done on the 49G, but IIRC, it was mostly cosmetic (although the layout did allow them to increase the total number of keys while appearing less cluttered than the 48). Under the hood, it was basically the same as the 48, except instead of an expansion slot and IR port, it had an extra 1.5 MB of flash memory hardwired in. The main improvement was software, and that was mostly cribbed (presumably with permission and/or help) form andre schorlrl's HP48 programming/hacking forum, wh

    • by jbolden ( 176878 )

      Everyone said it. She gutted HP. HP was an engineering company when she got there that made great devices in many areas. I can understand going where the money was, but I wish they had sold off the engineering divisions to someone who was interested in those more niche markets.

  • My 41CV died a couple of years ago, and I packed in the hell box. Display bled out and was unreadable, and I didn;t bother to get it repaired.

    And I have a bunch of modules for it, financials mostly. And the wand, card reader/writer, blank overlays by the pound, stacks of solution books. I worked for a dealer... I also had a 67, but traded it in for th 41CV. And I had use of a 97 in between, but I never got very good at using it.

    But - using the 41CV for balancing my checkbook was a blast. Organize it cor

  • Thankfully, those of us who use emacs just run M-x calc to get back to an RPN calculator which actually calculates numbers. (It's pretty much the main reason why my 48gx sits on my shelf waiting to be used.)

  • Like a screwdriver (Score:4, Interesting)

    by synthespian ( 563437 ) on Thursday May 05, 2011 @07:31PM (#36042682)

    This calculator is like a screwdriver: a perfect fit for the task.

    The Platinum shipped with a bug. The 12C...well, there are no bugs.

    RPN is great. Once you get used to it, you never look back. BTW, RPN is what the Forth programming language uses.

    When doing financial calculations or shopping I always take it with me. Also to the bank. It creates an instant bonding between you and the manager (those initiated in HP 12C's RPN).

    HP calculators, IIRC, were used to calculate the orbits in some early space program missions (YouTube). I think it's safe to say that the 12C is more numerically trustworthy than some Pentiums that came out....

  • by dtmos ( 447842 ) * on Thursday May 05, 2011 @07:36PM (#36042730)

    The "C" suffix stood for "continuous memory", meaning that programs and data did not disappear when the calculator was shut off. Like what every calculator does today. Before then, however ...

    My first HP was the HP-25, a glorious invention when it came out in 1975. It had 49 programming steps, and the program had to be re-entered from the keyboard, line-by-line, every time the calculator was turned off. My first real programming success came when a high school math teacher, trying to show how hard it was to determine whether a given number was prime or composite, asked my class to determine whether the number 300,000,007 was prime or not. (Thirty-five years later, I have not forgotten that number, and don't think I ever will.)

    I was able to program a test for primality into the HP-25. It was brute-force, of course -- checked for an integer result when the argument was divided by two, and then every odd number from three up to the square root of the argument -- but it worked, and I was able to show that 300,000,007 was prime. The teacher was impressed, both with the calculator and with the fact that such a large number that she picked out of the air at random turned out to be prime. (I don't think she new or cared about programming.)

    I love that calculator. The HP-25C came out the following year, and the HP-25 became an orphan, but I still have it -- along with an HP-48G+ purchased about 12 years ago. (Finding a new calculator with RPN turned out to be harder than I thought.)

  • I always thought RPN was a ridiculously complicated way to evaluate expressions. Looking back after having seen the light, I don't see how I would have made it through two engineering degrees without it.
  • by Flector ( 1702640 ) on Thursday May 05, 2011 @07:57PM (#36042938)
    The 9 key on the HP 12-C, Platinum edition is not reliable after being pressed a few thousand times. This has been reported by many finance types, and makes the platinum unusable.
    • The new HP calculators are no longer designed and manufactured by HP. It has all been outsourced to Taiwan/China and Singapore.
  • by roc97007 ( 608802 ) on Thursday May 05, 2011 @09:00PM (#36043486) Journal

    I first learned RPN in the seventies on my first calculator, an HP 45. When it was stolen in the eighties, I got an HP 16c which I still have and which still works flawlessly. At work I mostly use RealCalc on Android with radix and rpn modes turned on, but I also keep a 48C in reach. I *can* operate a regular calculator, but RPN makes so much more sense to me.

    My daughter took to RPN easily at 13 years old, but it confused her teachers so she had to go back to conventional notation.

To do two things at once is to do neither. -- Publilius Syrus