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From its introduction in 1979 until final production in 1990, the Hewlett Packard 41 Series Programmable Calculator reigned supreme as the trusted companion of professionals and students worldwide. Its instant success was due to innovation, quality and a well established base of loyal customers. The HP-41 became the object of fascination to a vast following of dedicated enthusiasts which sprang up to explore its intricacies and possibilities. Even today, its classic design makes it a useful and collectable tool with yet a few surprises left. This site is dedicated to documenting and preserving this amazing machine.

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The HP-41 Calculator Archives include an MCODE Emulator, VASM Listings, HP Digest and Owner's Manuals on CD, HP-41, HP-41C, HP-41CV, HP-41CX, HP41, HP41C, HP41CV, HP41CX, HP 41C, HP 41CV, HP 41CX, 41C, 41CV, 41CX, V41, MCODE, FOCAL, HP-IL, Synthetic Programming, VASM Listings, SDK41, HP Digest, NOMAS, HP Key Notes, PPC Journal, CHHU, Alvaro Gerardo Suárez, CHHU, David A. van Leeuwen, David Conklin, Edward Keefe, Eramco, Eramco Systems, Eric Smith, Frank Bauernoeppel, Gary Friedman, Hewlett-Packard, HrastProgrammer, Ian Hawkins, James Patterson, James Surber, Jean Francois Garnier, Jean-Daniel Dodin, John Dearing, Kane, Harper & Ushijima, Keith Jarett, Ken Emery, Kolb, Kennedy, Nelson, Leo Duran, Leslie Brooks and Jim De Arras, Meindert Kuipers, Microsoft, Mike Higgins, PPC, Ron van Tilburg, Skwid Ink, Southern Software, Stefan Seiwerth, Stephane Barizien, Synthetix, Tacit Logic Systems, Inc. (Eclipse Logic, Inc.), Ted W. Beers, Ted Wadman, Chris Coffin and Robert Bloch, Ulisse Quadri, VM Electronics, W&W Software Products GmbH, W.C. Wickes, Warren Furlow, William Hitchens, Zengrange, Games Pac, Advantage Pac, Financial Decisions Pac, Math Pac, Navigation Pac, Time Module, Wand ROM, ttCalc, V41, Windows 95 System Files, HP-41C/CV/CX ROMs, HP-IL Development Module, User Code Compiler, 82973A HP-IL Interface Card Software, SDS II, Southern Software LINK for HP-IL, Eramco ES-41, Hepax Module, PPC ROM, Profiset, Zenrom, Zeprom, SIM41, SDK41, NSIM, EMU41, User Code Utility, CCD Module, HP-41 Schematic, Swap Disk Programs, 65 Notes, HPX, PPC ROM Manual, PPC Journal, Better Programming on the HP-67/97, PPC Member Handbook, Computer Journal of PPC, Calc/41, Transfer/41, Lif2Dos, LIFUTIL, HP Journal, PPC Journal, Machine Design Pac, Stress Analysis Pac, Stat Pac, Circuit Analysis Pac, Structural Analysis Pac, Paname ROM, Extended IL ROM, HP Key Notes, Service ROM, User Code Utility GUI, Paname ROM User's Manual, V41 Source Code, HP-41E, HP-41E, Navigation Pac Manual, HP Digest, A Wealth of Accessories, HP-41CX Quick Reference Guide, HP-41CX Owner's Manual Volume 1, HP-41CX Owner's Manual Volume 2, Coconut VASM Listing, VASM Instruction Set Definition, Extended Functions VASM Listing, Advantage Pac Manual, Standard Keyboard Overlays, Card Reader Owner's Manual, Games Pac Manual, Math Pac Manual, 82143A Printer Quick Reference, RPN - A Logic Without Equal, Enter vs Equals, Copy Bankswitched ROM, HP-41 MCODE for Beginners, The HP-41 User Code Compiler Manual, Calculator Tips & Routines, HP-41 Quick Reference Card for Synthetic Programming, HP-IL Development Module Manual, The Ultimate Calendar, The Caves, Symbolic Logic: Summary & Applications, Advanced Star Trek, The HP-IL System, Eramco ES-41 Manual, Zenrom Manual, Hepax Module Manual Vol. 1, Hepax Module Manual Vol. 2, SDS II Manual, Southern Software LINK for HP-IL Manual, Synthetic Programming Made Easy, Zeprom Manual, Zeprom Notes, SDK41 Manual, Geometry, Real Estate, Mechanical Engineering, Physics, Fluid Dynamics, Lend/Lease/Savings, ELI-41/41SX User's Manual (CALC/41), ELI-IL Mass Storage & Printer Device Emulator Manual, XREF/41 Users Manual, Chemical Engineering, Surveying, Small Business, Solar Engineering, Civil Engineering, Chemistry, Notes, 82166A HP-IL Converter Technical Manual, Circuit Analysis Pac Manual, Extended I/O Module Manual, Paname ROM User's Manual, Extended IL ROM Manual, Business Stat/Marketing/Sales, Time Module Owner's Manual, Calendars, Time Module Solutions I, Games, 82162A HP-IL Thermal Printer Owner's Manual, 82163 Video Interface Owner's Manual, 82143A Printer Owner's Manual, Standard Applications Handbook, HP-41C Operating Manual, Series 40 Advanced Programmable Calculators, Test Statistics, High Level Math, HP-41C Service Manual, 82166C HP-IL Interface Kit Technical Guide, 82165 HP-IL/GPIO Interface; 82166 HP-IL Converter Manual Supplement, HP-IL Integrated Circuit User's Manual, HP-IL Interface Specification, Structural Analysis Pac Manual, Stress Analysis Pac Manual, Stat Pac Manual, Antennas, Electrical Engineering, Surveying Special Collection, Surveying Pac Manual, Civil Engineering Special Collection, Card Reader Quick Ref, Financial Decisions Pac Overlays, Financial Decisions Pac Quick Ref, Games Pac Overlays, Math Pac Overlays, Math Pac Quick Ref, Stat Pac Quick Ref, Surveying Pac Overlays, Surveying Pac Quick Ref, Time Module Overlay, Zenrom Overlays, HP Key Notes - V3N2-V9N8 Index, - PPC Index 2 -, Paname ROM User's Manual, Paname ROM User's Manual, MoHPC CD Set, V41, V41 Source Code, Real Estate Pac Manual, CCD Module Manual, CCD Module Quick Reference, eV41 Source Code, eV41, Series 40 Software Catalog, HP-41E49, HP-41E48, 82242A Infrared Printer Module Manual, HP-41X, MLDL2000 Specifications, Card Reader ROM, Extended I/O Module, Home Management Pac Manual, Games II, Control Systems, Users Library Solutions Programs, Surveying Pac, LandNav User's Manual, LandNav, A Whole New Standard, Price List, Price List, 82160A HP-IL Module Owner's Manual, Programming Pad, Series 40 Software & Accessories, HP-41C/CV Software & Accessories, Wand Owner's Manual, Pressure Sensitive Bar Code Labels, Plotter Module Manual, Home Management Pac, HP82180A Extended Functions/Memory Module, Financial Decisions Pac Manual, Time Module VASM Listing, Thermal & Transport Science Pac, Securities Pac, 82242A Infrared Printer Module, 82160A HP-IL Module, Plotter Module, HP-IL Cassette & Control VASM Listing, Firmware Design for HP-IL Devices, 82162A HP-IL Thermal Printer VASM Listing, HP-41C/CV/CX Service Manual, Clinical Lab and Nuclear Medicine Pac, V41 Source Code, V41, VB41CX Source Code, HP82180A Extended Functions ROM, HP-41 / HP-28 Comparison Brochure, 3421A Operating, Programming and Configuration Manual, 3421A Quick Reference, Molecular Weight Calculator, 3421A Brochure, 3421A Service Manual, 3421A Operating Note - Temp Cal Board, 44468A Data Acquisition/Control Pac Manual, 3468A Digital Multimeter Service Manual, 3421A Operating Note - 44463A Terminal Block Connector, 3421A Operating Note - 44466A Terminal Block Connector, 3421A Operating Note - 44469A Attenuator Resistors, 82160A HP-IL Module Quick Ref, Real Estate Pac, Petroleum Fluids Pac, 44468A Data Acquisition/Control Pac, Machine Design Pac Manual, VB41CX, V41, V41 Source Code, MHCalc, Control The World With HP-IL, 82161A Digital Cassette Drive Manual, Aviation Pac Manual, Aviation Pac, Synthetic Programming on the HP-41C, A Whole New Standard, Contributor's Guide, User's Library Program Submittal, Series 40 Handheld Computers, PPC CD Set, Using Your 9114 Disc Drive, 9114B Disc Drive Operator's Manual, Ultra-Trek, Securities Pac Manual, Thermal & Transport Science Pac Manual, Securities Pac Quick Ref, Securities Pac Overlays, Petroleum Fluids Pac Quick Ref, Petroleum Fluids Pac Manual, CCD Module Overlay, Circuit Analysis Pac Overlays, Home Management Pac Overlays, HP82106A Memory Module for the HP-41C, Plotter Module Overlay, Plotter Module Quick Ref, Stress Analysis Pac Overlays, Structural Analysis Pac Overlays, RIOWIO, HP-IL Integrated Circuit Register Map, Inside the HP-41, HP-41 / HP-28 Comparison Brochure, An Easy Course in Programming the HP-41, David Assembler, David Assembler Manual, Home Management Pac Quick Ref,iPhone,iPhone Calculator,iPhone HP-41,iTouch,iTouch Calculator