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HP reverse polish notation scientific calculator
me | today | me

Posted on 06/08/2009 6:54:44 PM PDT by mamelukesabre

My HP-48SX ceased functioning about 5 years ago and i still miss it. I recently got the bug to go out and replace it with something. I saw an HP-50 on sale today for about 60 bucks. I bought the 48-SX when they first came out(circa 1989?) for A LOT OF MONEY. I forget the exact amount, but it was either $199.99 or $299.99. I think it was the latter.

The only thing wrong with my 48 is the on/off button. I know this because the problem started out minor and gradually got worse. I used to be able to turn it on and off by pressing extra hard on the button. All the other buttons worked fine. Then little by little it(the on/off button) quit working completely.

I saved the calculator in hopes that I would find a way to fix it. I've tried spraying electrical contact cleaner into the keyboard and nothing works.

I was totally lost without that calculator for a long time after it quit functioning. I had an extra fat wallet for it that doubled as my checkbook. I never went anywhere without it.

This was before I had a cellphone and I'm pretty sure it was before anyone had a PDA. I turned my HP into a primitive PDA. It didn't have a touch screen or internet connection, obviously. But I had files in it with all kinds of personal info and my entire personal phonebook in it. There was lots of old stuff from college in there too.

I was still using payphones extensively back then...along with an answering machine at home that I could call up from a payphone to check my messages.

Since I got a cellphone, the HP became a little less important. I guess that's why I never replaced it. A buddy of mine told me he could program my HP to make the sounds of the phone numbers being dialed so I could hold the calculator up to the receiver of the pay phone and just let it dial like that automatically. He never did get around to doing that for me though...and so I never got to test it to see if it would work. It seems like it shoulda worked though. But I didn't know how to do it myself efficiently without redoing my entire phonebook. I wanted a program that would take a pre-existing stored number and convert it into the sounds required to dial a number. That was a little over my head.

Even to this day, sometimes when I pick up a simple handheld calculator and start punching in numbers real fast I accidentally revert back to RPN and have to start all over. IT REALLY SUCKS! And it's been 5 years since I've ever touched anything that uses RPN!


TOPICS: Computers/Internet
KEYWORDS: calculator; hewletpackard; hp; programmable; rpn
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To: mamelukesabre

I have noticed that a couple of their new calculators have switchable RPN addressablity. I beleive one of the 12c business versions and one of their scientific versions. I think some of their current graphing calculators are RPN but I do agree that their build quality for the new units isn’t what it was for the old ones.

I have an old 12c algebraic which I am used to. I have dropped it from my shirt pocket into water (I won’t say where or how I rinsed it off) and it still works after 18 years. Will use it till it dies.


101 posted on 06/10/2009 10:09:16 AM PDT by KC Burke (Men of intemperate minds can never be free...their passions forge their fetters.)
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To: Professional Engineer
That is indeed extremely manly. It goes well with this:
102 posted on 06/10/2009 10:10:17 AM PDT by starlifter (Sapor Amo Pullus)
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To: KC Burke

I think the reason for the switchable RPN is twofold:

Firstly...they are trying to attract the customer base that doesn’t comprehend RPN

Secondly...as I understand it, the REAL purpose of RPN back in the beginning was NOT to help out engineers and others that can do long tedious calcs faster with RPN. The real purpose was that the memory and the CPU were used more efficiently with a system designed around RPN. Nowdays, there’s no reason to worry about conserving computing power and there’s no such thing as a scientific calculator designed around RPN. If the calculator has RPN at all, it’s actually an RPN emulator that hogs more computing resources than if the RPN is switched off.

Computing power is all a moot point when it comes to a handheld calculator.

For instance...the HP 50G that I just bought for $60 has a 203 megahertz 32 bit CPU that is factory underclocked(presumably because there’s no cooling system in a pocket calculator and the power supply is limited to 4 AAA batteries) to 75 MHz and 512 Kilobytes of RAM. And it will accept a 2gigabyte SD flash memory card.

Compare that to my first IBM compatible computer that came with a 4 point something megahertz 8088 CPU(8 bit, iirc) and I forget how much RAM but I think it was 128K. The hard drive was under 20 megabytes...I wanna say 16MB but I can’t remember for sure.

This is my understanding, I’m sure someone will correct me if I got something wrong.


103 posted on 06/10/2009 4:06:08 PM PDT by mamelukesabre (Si Vis Pacem Para Bellum (If you want peace prepare for war))
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To: Always Right

I bought my HP11C in 1983. It still works great. I just don’t use it for programming any more. Other computers are much better. I love teh HP11C.


104 posted on 06/10/2009 4:10:07 PM PDT by huskerjim
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To: Always Right
I bought my HP11C in 1983. It still works great. I just don't use it for programming any more. Other computers are much better. I love the HP11C.
105 posted on 06/10/2009 4:10:41 PM PDT by huskerjim
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To: saundby

Well, I figured out the secret shortcut for “swap” and “review”. But I still havn’t figured out where the function is that converts a decimal into a quotient. I’m afraid they left it out.

Boy! This thing is really slow. One very deadly flaw of the 50G is that I can tap the buttons faster than the thing can register them. That’s not good.


106 posted on 06/13/2009 3:45:47 PM PDT by mamelukesabre (Si Vis Pacem Para Bellum (If you want peace prepare for war))
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To: mamelukesabre

I’ve been looking around to see if I an pick a 50g up for mysself at anything near the price you got. No luck so far.

On the keyboard, I’d been warned the default key response time is too slow. The fix is to set the KEYTIME variable to something like 1/3 to 1/4 the default time, e.g.:

400 ->KEYTIME (when in RPN)

You can write it as a short program and set it to run at startup (by naming it STARTUP, I’m told.) I understand that there’s an enhancement request in at HP to make the default time shorter, and user settable without resorting to a program.

I’m not familiar with the fraction functions, I’m afraid.


107 posted on 06/15/2009 2:42:27 AM PDT by saundby
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To: saundby

I guess I need you to walk me through this.

I typed in:

(alpha)(alpha) KEYTIME(alpha) (orange shift) (arrow) 400 (enter)

Then I typed:

’ (alpha)(alpha)STARTUP(alpha)(space)(STO)

Now there is a variable named “STARTUP” with the value “KEYTIME(arrow)400’

Turn off the calculator. start up the calculator.

Still no good. I can still tap the buttons too fast for them to register.

Then I trid this:

(orange shift)<<>> (orange shift)(CAT) (down scroll to “keytime->”) (ok)400(enter)’(alpha)(alpha)STARTUP(space) (STO)

still no good.

Then I tried:

(orange shift) <<>> 400(orange shift) CAT (scroll down) (keytime->) (ok)(space)(enter) ‘STARTUP’ (STO)

Then turn off HPm, then turn on HP.

Still no good.


108 posted on 06/15/2009 4:57:39 PM PDT by mamelukesabre (Si Vis Pacem Para Bellum (If you want peace prepare for war))
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To: mamelukesabre

If I had a 50g I’d write it down keystroke by keystroke. I just remembered having a coworker warn me about the problem when I was thinking of picking one up some time ago.

I found some info online, though:

Near the bottom of this document (item 9), it describes things:
http://www.student.montefiore.ulg.ac.be/~merciadri/docs/hp50g/hp50g.pdf

This talks about keystrokes when entering the commands some:
http://home.gwu.edu/~mvolz/hpcalc/

There’s a message in this thread that gives details, too:
http://www.physicsforums.com/showthread.php?t=157969

If I don’t turn up an HP-50g at something <$80 soon, I’ll probably pick up a 35s. I know it doesn’t have everything the 50g does, or even my HP-41CV/CX’s, but I’ve heard it’s as close as you can get to the “classic” HPs these days, and they go for ~$40.


109 posted on 06/15/2009 8:35:45 PM PDT by saundby
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To: saundby

Awesome dude.

That first link is crap. Their instructions DO NOT WORK.

The second link is the correct method. It works. And it appears to be permanent. I thought it would reset itself when you turn off the calculator, but it does not.

So apparently, who ever told you to store the program in “startup” is incorrect. This is totally not necessary. Perhaps if you pull out the batteries, THEN the calculator will reset itself. That I dont’ know. I didn’t try it.

The important thing to remember is to delete the automatic spaces inserted when you use the (orange shift) (zero key) sequence...makes you wonder what the purpose of those spaces is anyway?

Using the method in your second link, I thought maybe that series of keystrokes was merely a shortcut method of defining a variable named “keytime” and assigning it a value of 500. WRONG. After doing it i searched low and high for a new variable named “keytime”. None to be found anywhere in calculator. Creating a variable named “keytime” obviously does NOT work.

After you told me you are having trouble finding one of these little guys for $60.99 or even under 80bucks, I’m sitting here wishing there had been a bunch of them at best buy and I bought them all up. They only had one left though. Maybe that’s why it was so cheap...marked down from $139.99

I’m finding another annoyance with the 50G. The “purge” command is in a very unfortunate and inappropriate place...unless there’s another super secret shortcut I don’t know about. I’m gonna scour those links you gave me. I already searched the CD that came with it. Nothing.

And my eyes seem to be unwilling to adjust to the 50G’s “divided by” button. They really did screw up when they layed out the keys on the 50G. It’s obvious the enter button was originally meant to be in the same old HP standard location. But then they moved it to the “+” key and then shifted all the operator keys(+,-,x,*,/) up one spot. Doing so pushed the “/” key up into the smaller buttons. My eyes can’t find it. they insist on looking for a large button the same size as all the other operators.

The other thing that I can’t adjust to is the spacing between the buttons. The older HPs had more space between the buttons, and the buttons felt like they stuck out higher. That made it easier to find the buttons quickly(by feel) without needing to focus your eyes directly on each button as you tapped each one.

And finally, the color yellow was a really dumb idea. ON the 50G, the alphabet is printed in dull yellow. I CANNOT SEE IT. Really aggravating.


110 posted on 06/16/2009 3:52:04 PM PDT by mamelukesabre (Si Vis Pacem Para Bellum (If you want peace prepare for war))
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