Model:-91AGeneral:Name:Scientific Portable Printing CalculatorCode-Name:Felix (Topcat?)Family:TopcatLogic:RPNFeatures:scientificFirsts:TopcatIntroduction:Date:1976-3-1Price:$500Discontinuation:Date:1979-01-01Price:$325 (price change 1977-04-01)Production-Run:?Display:Type:LED, 7 segmentSize:1 line x 15 charsNumber-Formats:sign, 10 mantissa, ., exp sign, 2 expAnnunciators:red light for low batteryData:User-Visible:Smallest:1E-99Largest:9.999999999E99Signif.-Digits:10Internal:Smallest:1E-99Largest:9.999999999E99Signif.-Digits:10Data-Types-and-Sizes:real, 7 bytesMemory:Named-Registers:X, Y, Z, T, Last x, 0-9, .0-.5Flags:noneRegister-Usage:R.0\GSnR.1\GSxR.2\GSx^2R.3\GSyR.4\GSy^2R.5\GSxyNumbered-Registers:16Program-Steps:noneProgram-Editing:noneProgram-Display:noneUser-RAM-Bytes:147Total-RAM-Bytes:?ROM-Bytes:?Machine-State:prefix key statestack lift enabledisplay moderegistersFile-Types:nonePhysical:Technology-Used:?Processor:?Chip-Count:?Power-Source:custom battery pack, A/CContinuous-Memory:noExpansion-Ports:noneI/O-Ports:thermal printer, 17 columns?Clock:noneLength:?Width:?Height:?Weight:?Temperature-Range:Operating:0 to 45 deg CCharging:15 to 40 deg CStorage:-40 to 55 deg CKeyboard:Switches:OFF / ONMAN / ALL / NORMDEG / GRD / RADShift-Keys:gold, gold, belowUser-Defined-Keys:noneKey-Arrangement::              ** ** ** *****              ***** ** ** **** ** ** **   ** ** ** ** **** ** ** **   ** ** ** ** **** ** ** **   ** ** ** ** **                          **** ** ** **   ***** ** ** **Key-Labels-Base-Keyboard::x<>yRvR^PRINT xENTER^CHSEEX\:- 2 x\v/xxy1/xSTO789xSINCOSTANP->RRCL456-%%\GSy^R->PCLx123+ xeLN\GS+[]0.FIX+Key-Labels-gold-gold-below::[][][][]LIST:STACK------REG-----\GSCL REGH.MS+H.MS-->H.MSH.MS->\pi[][][]CL \GS   -1   -1   -1SINCOSTANsLAST x[][][][]\GD%N!L.R.x-CLEAR[][][][]  x10LOG\GS-[][]ENGSCI[]Programmable-Operations::noneNon-Programmable-Operations::%percent of%\GSpercent of total+addition-subtraction->H.MSconvert to hours,minutes,seconds0-9, .enter digit or decimal pointshift 0-6clear shift1/xreciprocal10^xcommon exponentiationCHSchange signCL REGclear the registersCL \GSclear the statistics registersCLEARclear the calculatorCLxclear XCOScosineCOS-1arc cosineEEXstart an exponent, 1 not requiredENTER^entere^xnatural exponentiationFIX 0-9fixed decimal modegoldshiftH.MS+h.ms additionH.MS-h.ms subtractionH.MS->convert to decimal hoursL.R.compute linear regressionLAST xLAST XLIST:REGprint the registersLIST:STACKprint the stackLIST:\GSprint the statistics registersLNnatural logarithmLOGcommon logarithmN!factorialP->Rconvert polar to rectangularPRINT xprint the X registerR->Pconvert rectangular to polarRCL 0-9,.0-.5recall from registerRvroll the stack downR^roll the stack upscompute standard deviationSCI 0-9scientific notation modeSINsineSIN-1arc sineSTO +,-,x,\:- 0-9storage arithmeticSTO 0-9,.0-.5store in registerTANtangentTAN-1arc tangentxmultiplicationx-compute averagex<>yexchange x and yx^2squarey^linear estimate, correlationy^xpower\:-division\GD%percent change\GS+add to statistics\GS-subtract from statistics\piconstant, value 3.141592654\v/xsquare rootMenus::noneBugs/ROM-Versions::noneNotes::Seven keystroke typeahead buffer.  Page 201 of the manual has a niftyexploded-view drawing of the calculator.  Page 73 of the manual has anifty formula (see "problems").