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   Matt McIrvin (mattmcirvin@mathstodon.xyz)'s status on Tuesday, 06-Feb-2024 01:13:53 JST Matt McIrvin

   in reply to

   HP's scientific calculators were quirky in that most of them until quite recently solely or primarily used postfix or Reverse Polish Notation (RPN), a stack-based system in which every operator followed its operands: to add 2 + 3, instead of

   2 + 3 =,

   you'd press

   2 [ENTER] 3 +.

   These calculators had a stack, that is, a list of numbers represented as a vertical tower that they would generally enter and exit from the "bottom" (in HP's terminology, at least). In the addition above, the ENTER key would signal that you were finished typing a number and put the 2 on the stack. The + would implicitly do an ENTER if necessary, then take the bottom two items off the stack and add them.

   For more complex calculations, there was no messing around with order of operations or nested parentheses--the stack was everything. So, say, (4+5) * 3 - 2 could be entered as

   4 5 + 3 * 2 -

   (where it's understood you type ENTER after every number not followed by an operator.)

   The joke was that an advantage to using an HP was that nobody ever asked to borrow your calculator more than once. But for complex calculations off the cuff, people who used them soon learned to prefer RPN to algebraic entry, and I still like it.

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     Matt McIrvin (mattmcirvin@mathstodon.xyz)'s status on Tuesday, 06-Feb-2024 01:13:55 JST Matt McIrvin

     I've been reminiscing a lot about calculators lately. I started learning math just when electronic scientific calculators were replacing slide rules as tools for engineers.

     But scientific calculators are themselves almost extinct outside of the classroom, because computers, smartphones and tablets running powerful CAS or numerical software can do all the kinds of computing you really need... unless you're not allowed to use them because of classroom or exam restrictions.

     So the market has contracted to education, and the high-end calculators sold today, though they're extremely powerful, are very much catering to students rather than to engineers or scientists. There's a lot of power siloed into user-friendly apps, but less ability to link those together into powerful custom-built systems of your own design.

     And inevitably, because I'm getting old, I have a lot of nostalgia for old ones... particularly for HP's RPL line, starting in the late 1980s with the 28C (which was woefully underpowered, but the potential was there) and continuing through the very capable 28S and 48/49/50 series.

     The ones I actually had were the 28S and the 48SX--the latter got stolen after just a few years; it was too damned expensive to leave lying around. I still have the 28S somewhere though the batteries for it can be hard to find. But I've been getting back into messing with them through emulation. Here's Calculator Culture's review of the 48SX that goes through its innovations, strengths and weaknesses.

     https://www.youtube.com/watch?v=yujtxo5efbE

     Haelwenn /элвэн/ :triskell: likes this.
     phiofx repeated this.