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[0] https://play.google.com/store/apps/details?id=org.ab.x48
Those two items were status symbol back then.
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 th…
I was one of these smug HP calculator owners back in high school and college. I loved it and spent hours hacking on it (and also secretly enjoyed the fact that nobody borrowed it since hardly anyone knew how to use it).
Years later, I started realizing that the reason why these calculators do take fewer keypresses to make calculations is because they borrow your brain to assist them.
For example, you see `3 * (2 + 4)` and your brain has to identify the most nested parenthesis expression, type that in and work your way out. It works well enough for simple expressions but doesn't really scale very far beyond that.
Remember this SETI program that used people's idle CPU's to scan sky pictures? I felt HP calculators had been pulling the same trick by borrowing your brain to calculate their expressions.
I felt that I had been cheated but I wasn't really mad about it because I loved these calculators so much.
I never personally saw this, but I've been told by people that the HP-41 could be massively overclocked at the cost of heavy loss of battery life. Supposedly they could be overclocked sufficiently to handily beat common minicomputers, such as the PDP-11, at floating point. Allegedly some people hacked interfaces between their PDP-11 and their overclocked HP-41 that allowed the PDP-11 to use the calculator as a floati…
The HP 41 had something called "synthetic programming", a flaw that someone once found in the calculator that allowed access to a lot of its internals, including brand new opcodes and capabilities (even graphics, which the HP 41 didn't officially support).
The downside was that doing the wrong thing could cause the calculator to shut down sometimes for days in a row. I once did that to my father's calculator and these were the longest days in my life, dreading that I might have broken his $300+ purchase for silly programming antics.
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If you're enjoying that, you'll find even more connections with Forth, also a very cool programming language. https://en.wikipedia.org/wiki/Forth_(programming_language)
I love stack languages. Forth, Factor, Joy, Cat .. (all the concatenative crew). ps: there are some Chuck Moore talks on youtube that are worth gold. His CPUs are heaven
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[1 3 Enter 3 + 4 Enter 2 × ÷] is 10 button presses for RPN. [1 3 + 3 = ÷ 4 ÷ 2 =] is also 10 button presses, and how I would have entered it on an infix $10 TI-30XA during an exam. (At least, it's how I would have entered it if the figures weren't so small.) You could argue that it's cheating to "cook" the input beforehand so that the '4×2' divisor becomes two '4' and '2' divisors, but then you would have to ignore t…
LOL why bother with a calculator? 16 ÷ 8 easy! I always think of RPN as somewhat akin to using VIM (editor), once you learn it, it becomes unconscious, automatic. I for one don't see how the RPN form relies "on a more extensive cook".
> At least, it's how I would have entered it if the figures weren't so small.
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Yes, bad example. See here: http://calculatorauthority.com/why-use-a-reverse-polish-nota... >For example, we want to compute “(13+3)÷(4×2)” using a calculator of algebraic notation (not a scientific one) then we have to do many steps to reach the answer. Firstly, we have to compute “(13+3)” and then we will save the answer to the memory of the calculator. Then we have to compute the calculation in the denominator i.e…
[1 3 Enter 3 + 4 Enter 2 × ÷] is 10 button presses for RPN. [1 3 + 3 = ÷ 4 ÷ 2 =] is also 10 button presses, and how I would have entered it on an infix $10 TI-30XA during an exam. (At least, it's how I would have entered it if the figures weren't so small.) You could argue that it's cheating to "cook" the input beforehand so that the '4×2' divisor becomes two '4' and '2' divisors, but then you would have to ignore t…
There is no "cooking" in the RPN input, the way you input is a little more similar to how you do manually operations, and in the order numbers are written from left to right, but of course beauty is only in the eye of the beholder.
A (as well small) advantage is that on RPN you "see" that you are dividing 16 by 8, particularly - as hinted previously - when you have a RPN calculator that allows you to visualize the stack you can see better "partial" results.
Now be nice, and do (13+3)/(3x(SQR(4+2))).
[1 3 Enter 3 + 3 Enter 4 Enter 2 + SQR * /]
One day I came across it and started noodling. Pretty soon figured out you could program the calculator to do the main calculations for my job. What was supposed to be an all-Summer project ended up finished in less than two weeks! (I still got paid for the whole work. Thanks Dad!)
That was my first taste of how programming machines can save time.
A few years later I bought myself an HP-41C with a card-reader attachment and then discovered 'synthetic programming' (one of the earliest versions of 'jailbreaking').
These were all gateway drugs. Have been hooked on programming ever since.
Thanks for bringing back all kinds of fond memories.