hp17bii

Model:	17BII, differences from -17B

General:
	Code-Name:		?
	Logic:			RPN, algebraic, no precedence
	Firsts:			first dual logic machine (with 19BII)
	Introduction:
		Date:		1990-1
		Price:		$110
	Discontinuation:
		Date:		<2003-01-01
		Price:		?
	Production-Run:		?

Memory:
	Named-Registers:	4 line history, line 2 is LAST or X, Y, Z, T,
				last X; 0-9
	Machine-State:		prefix key state
				RPN/algebraic mode
				stack lift enable
				pending operations
				printer status
				display contrast
				display mode
				radix mark
				registers and history
				statistics lists
				CFLO lists
				alarms
				current application and invocation history
				time and time format
				memory

Key-Labels-Base-Keyboard::

(The = key has a lower label of ENTER.)

Key-Labels-gold-gold-above::

[]	[]	[]	[]	[]	[]
[]	RND	MATH	MODES	PRINTER	MAIN
CLEAR DATA	E	Rv	x<>y	[]
[]	[]	[]	[]	1/x
				 x
[]	[]	[]	[]	y
[]	[]	[]	[]	\v/x
				 2
OFF	MEM	SHOW	LAST	x

Non-Programmable-Operations::

(		start nesting or Rv
)		end nesting or x<>y
=		complete operation or ENTER
INPUT		use number in line 1 as response or ENTER
LAST		use number in history line 2 or Last X
Rv		roll down
x<>y		exchange x and y
^		move to previous item or roll up

Menus::

MODES:	BEEP	PRINTER	DBL	ALG	RPN
(DBL is double spaced printing.)

Bugs/ROM-Versions::

There is an oddity in the RPN stack of this (and the 19bii) in that
the stack ranges in size from 1 to 4 entries, depending upon how
much data has been entered.  For example, if you do:

	- switch to RPN mode
	- 1
	- Enter
	- 2
	- Rv
	- Rv

You will see "2" in the display, not zero.

(from Wlodek Mier-Jedrzejowicz)

Early models of the HP17BII have a bug which is activated when the
HP17BII is in RPN mode and the [+/-] and [x<>y] keys are pressed one
after the other. A harmless way to see the bug is as follows:

1. Put a positive number on the stack, for example press 9 and [INPUT].
2. Change the sign by pressing the [+/-] key next to [INPUT].
3. Exchange x and y by pressing the key with x<>y above it.
4. Now type a digit, for example 8; you will see a minus in front of it.
(This is the bug; after +/- to change a positive number to negative,
immediately followed by x<>y and a number, the number has a spurious
minus sign placed in front of it.)
5. Press [INPUT] and you will see the number is really positive.
6. Type another number; it will again have a minus sign.
7. To deactivate the bug safely press the [CLR] key.

The bug is dangerous, if you get to step 4 and see a number which is
negative though it should not be, you might be tempted to press the
backarrow key to remove the number and the minus sign. Since the minus
sign is not really there, if you try to delete it, you confuse the
calculator - it stops for a moment, then clears the stack and displays
the MACHINE RESET message. The bug can also lock up your keyboard - in
that case you should reset the calculator by pressing the [CLR] key
and the third key from the left in the top row both at the same time.
If you ever see the bug, press [CLR] at once to kill it!

There are some variations on the bug. If you type a number,
immediately change its sign, then press x<>y, the calculator will beep
and refuse to swap x and y. If you press the rolldown key next to
x<>y, that will beep and refuse to work too. If you press the
backarrow key until only the minus sign is in the display, then press
[INPUT] or try to use this minus sign, nothing will work except that
the [-] key will put a second minus in the display. If you do steps 1
through 4, then press [INPUT], [+/-], x<>y, and a digit key again, you
will see two minus signs, and you can repeat this process adding one
more minus sign each time. If you press [CLR] now, then type a number,
press [+/-], [INPUT], x<>y, [+/-], x<>y and then a digit key, you will
see a zero (if the display mode is ALL) or a fraction mark (if the
display mode is FIX) in front of the digit instead of a minus.

It can also appear whenever there is a negative number already on the
bottom of the stack when CALC is pressed in the Solver, any typing of
a new value also generates strange stuff in the display, and the
backspace key not only causes a warmstart, but has given me a "memory
lost" as well (it serves me right for entering so many l-o-n-g
formulas into such a small machine ;) [ reported by John H. Meyers
<jhmeyers@mum.edu> ]

The same bug exists in early HP19BII models, though it behaves a little 
differently. It was removed early in 1991.

Notes::

This version also has a double-spaced printing mode.

The solver in this machine is exactly the same as that of the 19bii
and includes all 19bii functions even if not documented, including Let
and Get.

The XYZT stack is allocated dynamically as needed, so doing a Rv
someetimes results in rolling fewer than four values.

There was a MAJOR rework in 2008, but the model number didn't change.