Model:17BII, differences from -17BGeneral:Code-Name:?Logic:RPN, algebraic, no precedenceFirsts:first dual logic machine (with 19BII)Introduction:Date:1990-1Price:$110Discontinuation:Date:<2003-01-01Price:?Production-Run:?Memory:Named-Registers:4 line history, line 2 is LAST or X, Y, Z, T,last X; 0-9Machine-State:prefix key stateRPN/algebraic modestack lift enablepending operationsprinter statusdisplay contrastdisplay moderadix markregisters and historystatistics listsCFLO listsalarmscurrent application and invocation historytime and time formatmemoryKey-Labels-Base-Keyboard::(The = key has a lower label of ENTER.)Key-Labels-gold-gold-above::[][][][][][][]RNDMATHMODESPRINTERMAINCLEAR DATAERvx<>y[][][][][]1/x x[][][][]y[][][][]\v/x 2OFFMEMSHOWLASTxNon-Programmable-Operations::(start nesting or Rv)end nesting or x<>y=complete operation or ENTERINPUTuse number in line 1 as response or ENTERLASTuse number in history line 2 or Last XRvroll downx<>yexchange x and y^move to previous item or roll upMenus::MODES:BEEPPRINTERDBLALGRPN(DBL is double spaced printing.)Bugs/ROM-Versions::There is an oddity in the RPN stack of this (and the 19bii) in thatthe stack ranges in size from 1 to 4 entries, depending upon howmuch data has been entered.  For example, if you do:- switch to RPN mode- 1- Enter- 2- Rv- RvYou will see "2" in the display, not zero.(from Wlodek Mier-Jedrzejowicz)Early models of the HP17BII have a bug which is activated when theHP17BII is in RPN mode and the [+/-] and [x<>y] keys are pressed oneafter 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 spuriousminus 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 isnegative though it should not be, you might be tempted to press thebackarrow key to remove the number and the minus sign. Since the minussign is not really there, if you try to delete it, you confuse thecalculator - it stops for a moment, then clears the stack and displaysthe MACHINE RESET message. The bug can also lock up your keyboard - inthat case you should reset the calculator by pressing the [CLR] keyand 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 beepand refuse to swap x and y. If you press the rolldown key next tox<>y, that will beep and refuse to work too. If you press thebackarrow key until only the minus sign is in the display, then press[INPUT] or try to use this minus sign, nothing will work except thatthe [-] key will put a second minus in the display. If you do steps 1through 4, then press [INPUT], [+/-], x<>y, and a digit key again, youwill see two minus signs, and you can repeat this process adding onemore 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 willsee a zero (if the display mode is ALL) or a fraction mark (if thedisplay mode is FIX) in front of the digit instead of a minus.It can also appear whenever there is a negative number already on thebottom of the stack when CALC is pressed in the Solver, any typing ofa new value also generates strange stuff in the display, and thebackspace key not only causes a warmstart, but has given me a "memorylost" as well (it serves me right for entering so many l-o-n-gformulas 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 19biiand includes all 19bii functions even if not documented, including Letand Get.The XYZT stack is allocated dynamically as needed, so doing a Rvsomeetimes results in rolling fewer than four values.There was a MAJOR rework in 2008, but the model number didn't change.