Quote from jtnet:
what is RPN? and i still dont get it
RPN = Reverse Polish Notation.
RPN is a parenthesis free way of writing algebraic expressions, which was
first invented by the logician: Jan Ã
Âukasiewicz. So for example the expression
(w+x) / (y - z) would be written in reverse polish notation as: wx+yz-/. The
operands (wx) precede the operator +, hence it's called reverse notation
and Ã
Âukasiewicz was Polish so ...
The point for calculators is that this notation makes it a lot
easier to evaluate complicated numerical expressions and reduces the number of
keystrokes you need.
The HP calculators have a small internal memory stack, which implements
the RPN algorithm, and an [enter] key which pushes values you type into the
keyboard onto the stack. Operations like + , - , x, / work on the first two
entries on the stack, and you just press the [+] key to add them, for example.
There are other special keys for moving values around on the stack, too.
This may sound complicated, but it is actually much simpler and faster to use
once you get used to it than the algebraic notation calculators with
parentheses and equals keys.
So for example on an HP to calculate the value of:
(3.2 * (2 + 3)) / (1 + (4*(5+6)))
you could just type [3.2] [enter] [2] [enter] [3] [+] [*] [5] [enter] [6] [+] [4] [*] [/].
Once you learn it, you never want to switch back to a calculator that
doesn't use RPN ... at least I never wanted to
dchang0:
Great summary of the features that made the HP calculators something
special. RPN is much superior to algebraic notation, and it was the main thing
that made the HP hand-helds superior to TI from my point of view.
The only thing I think you left out was that the old HPs were programmable,
which was something special in the days before PCs, when you still had to line
up for access to a mainframe.
I still have an old 11C, which was the scientific version of the 12C.
http://www.hpmuseum.org/hp11c.htm
This particular model was well-liked enough that it's become sort of a cult
item. I've seen them selling for > $400 on ebay. Even with damage they're
offered at prices upward of $200.
http://cgi.ebay.com/Vintage-HP-11C-...1QQcmdZViewItem
The only way they're going to get mine, though, is from my cold dead hands
