Welcome to

- Introduction
- A bit of personal history
- My calculators
- My slide-rules
- Other stuff
- The coherence test
- Resources for calculators
- Resources for slide-rules
- Official Resources

Last Added: TI-1650 and TI-5050M (both not working)

- a need, because I'm a civil engineer, and do many calculations every day, so a good calculator is a must
- a toy, because I love programming them (and playing with graphics, matrices, complex numbers, symbolic math, solving or integrating capabilities)

That's when and how I learned appreciating both programmable calculators and the technology behind them.

Of course, after fighting against the limits of the PC-1401, during 1991 I resolved to update my park. Notice that I didn't need any substitution for failure, only a real improvement, and that I had no collector's intent. Being culturally adapted to Sharp (what a mistake this way of thinking!), I opted for a Sharp PC-E500; figure out: 28 Kbytes, graphics, four lines of forty characters (!), lowercase letters, an improved BASIC and still the pleasant, familiar built-in algebraic calculator aside. I fell in love.

Later I had to wake up. Gum keys tend to become... hem... tardy. For instance the "1" key had to be pressed twice to get a number, and the "0" returned two or three digits at a keystroke. When I realized this, I got back to the PC-1401, because its keys were and still are better. And so I finished my examinations with two calculators, being the PC-1401 my "portable" choice.

I was then the proud owner of three calculators. When in 1998 I changed my job position, I decided to buy a new calculator (the very first I could buy on my own: the previous ones were gifts by my parents), and the HP-32SII was my choice. Why? Well, my boss has been a fierce owner and user of HP-calculators since his school days, and he owned and owns many HP models (HP-97, HP-21, HP-11C, HP-32SII): he had always tried to convince me that RPN is better. He made it, in the end. I found myself at "home" immediately with my HP-32SII, devouring the manual in hours, and starting to program and inputting equations at once. So my entry in the HP world was fully accomplished.

In 2001, I discovered the HP Museum, realizing that there are many many models even more attractive than mine, and so I started buying some from Internet. The first was a brand new HP-12C bought the same year at a British e-store, then followed by a used HP-11C from a German guy (2003) and then by a used (but in wonderful conditions) HP-15C from an American guy (2005).

In February 2006 something ugly happened: my HP-32SII, while I was doing a calculation, buzzed like a bee and then stopped working: I couldn't even reset it. After a couple of days it got back, but since that day (February 11, 2006) I stopped using it as my current calculator. I looked around and phoned some poeple, got a number of a guy who worked in a HP Assistence Laboratory and asked him what I could do, but he told me there was nothing to do: Pioneers won't open without damage. I bought a HP-49g+ in substitution, then a HP-33S, but I was unsatisfied. So (I mean, after beginning to realize that my interest was becoming some sort of collector's feeling), I decided to look around in my hometown to see who sold calculators: no HP dealers, but I found out a shop with a back shelf full of old unsold 1980s and 1990s machines, some of which I could buy quite for nothing - mainly Casio models. My collection had started up.

In mid 2006 I bought another used HP-32SII from Belgium, to replace (for usage, not into my heart) the unstable one.

RPN Calculators

RPL Calculators

Algebraic Calculators

Equation Calculators

Adding Machines

Checkbook Calculators

RPN Calculators

RPL Calculators

Algebraic Calculators

Equation Calculators

Adding Machines

Checkbook Calculators

Now, a personal story. When I was a boy, there was a slide-rule on my father's desk (the AFVM Rietz 12.5), and one day he taught me its basic usage. After all, that instrument was his personal calculator during his high school years! Of course, I forgot everything a minute later: it seemed to me a very good and fast way to mess one's life up. During my high school, though, I used to keep it with my pens and pencils, and to play around with it (after all, I was the only one in my classroom owning a slide-rule!). So I began (I don't remember when) a thorough personal study about it, without manuals or third-parts instructions. To be honest, I learned quite immediately to multiply (and divide), but the remaining functions have been a mystery to me for a long time. I ended up using it as an improved ruler, but I didn't use it to calculate. It's only when I started my collection that I began to re-study the matter, and so I bought some more for a bunch of money.

Slide-rules

Manufacturer | Model | Scale length (cm) | Standard scales | Extra scales |

Antica Fabbrica Vittorio Martini | Rietz | 12.5 | K, A, B, Ci, C, D, L | none |

Diwa | 601.1 Rietz | 12.5 | K, A, B, Ci, C, D, L | S, ST, T |

Nestler | 121 Rietz | 12.5 | K, A, B, Ci, C, D | P, S, T, LL1, LL2, LL3 |

Aristo | Scholar 903 Rietz | 25.0 | K, A, B, Ci, C, D | L, S, ST, T |

Type | Abilities | Notes |

Casio
SF-4300B digital diary |
32 Kbytes for data, but who cares? |
A relic. There's a four-ops
built-in algebraic calculator. |

Sharp EL-6150 memo diary | 4 Kbytes for data, phones and calc | A relic. It reports "Electronic calculator" on the box, but it isn't true! |

Abacus
(pocket metal model) |
sums involving results up to 90 |
A Chinese 2x5x90 abacus |

Directional
compass |
the four basic directions |
A Russian compass - yes, it calculates
directions! ;-). |

- Casio SL-310M Instruction Sheet (en+)
- Casio SL-760GDB Instructions Sheet with pouch (en+)
- Digita VV 39 (it)
- HP-12C User Guide (en - it's a supplementary copy: each 12C has its own)
- HP-12C Real Estate Applications Handbook (en - not sold with the calculator)
- HP-28S/HP-28C Probability and Statistics (en - 1988 edition)
- HP-28S/HP-28C Probability and Statistics (en - 1990 edition)
- HP-34C User Manual + quick guide (it)
- HP-34C Application Book (it)
- HP-48SX User Guide (it - 2 volumes)
- HP 82240B Infrared Printer Manual (en)
- Sharp EL-211 Instruction Sheet (en+ - two copies)
- Sharp EL-506P Manual (en+)
- Sharp EL-5812 Manual (it+)
- Tecnosonic LC18 Instruction Sheet with plastic pouch (it)
- TI-52/52 Solar Manual (en+)

- (the best site ever!) The HP Museum, devoted to HP calculators in http://www.hpmuseum.org
- (a must!) The Viktor Toth's R/S Key Database in http://www.rskey.org
- (a hit!) The Vintage Technology site in http://www.vintage-technology.info/, even for radios, transports and voltmeters; see the page about calculators dating in http://www.vintage-technology.info/pages/calculators/general/calcdate.htm
- (a pearl!) The Voidware site in http://www.voidware.com
- (mythic!) The DataMath Calculator Museum devoted to Texas Instruments calculators in http://www.datamath.org
- HPCalc.org in http://www.hpcalc.org/
- HPedia is hosted in http://www.hpcalc.org/hp48/docs/hpedia/
- HPCC site (Making the most of your HP calculator) in http://hpcc.org/
- Rick Furr's Hewlett Packard Calculator Page in http://www.vcalc.net/hp.htm (here you can buy the HP calculator poster)
- The Calculator Repair Knowledge Base in http://www.rskey.org/calckb.htm
- The MyCalcDB site in http://mycalcdb.free.fr/main.php?l=0&p=1; a section in http://mycalcdb.free.fr/main.php?l=0&p=3 will show you how to date, clean, repair, open/disassemble, store your calculator. The site is in English and in French
- The Museum of Pocket Computers in http://www.pocketmuseum.com/index.html
- The Pocket Calculator Show in http://pocketcalculatorshow.com/calculator/
- Craig Finseth's HPDATABase in http://www.finseth.com/parts/hpdata.php
- Massimo Gnerucci's beautiful site about HP calculators in http://emgee.altervista.org/html/calculators.html
- Matthias Wehrli's HP-Collection in http://www.hp-collection.org/
- The RPN calculator site in http://www.rpncalculator.net/
- The Calculator.org site in http://www.calculator.org/
- HP Home View in http://members.iinet.net.au/~ccroft/
- Old HP and TI Calculators by Gene Wright in http://www.rskey.org/gene/hpgene/
- Old Calculator Museum in http://www.oldcalculatormuseum.com/
- The Calculator Reference in http://www.vcalc.net
- Ernst Mulder's calculators collection in http://ernst.mulder.com/calculators/
- On Lolo's pages devoted to Sharp calculators (mostly in French) in http://destroyedlolo.homeunix.org/sharp/
- The Vintage Calculators pages in http://www.vintagecalculators.com/
- Eric Smith's Eccentric Emporium of Egregiously Effervescent Effluvium, Etc. in http://www.brouhaha.com/~eric/hpcalc/ where interesting details about HP calculator internals are explained
- Maria Mortati's mechanical calculator site in http://www.mortati.com/glusker/
- The X-Number world of calculators in http://www.xnumber.com/xnumber/ with a history of calculation in http://www.xnumber.com/history_pages/history1.htm
- Tony's Taschenrechner-Sammlung Calculator-Collection (partly in German) in http://www.thimet.de/CalcCollection/Contents.html
- The Collection of Calculating Devices in http://www.tcocd.de/
- Kenneth Kuhn's Online Museum in http://www.kennethkuhn.com/hpmuseum/
- Bob Bruner's notes about scientific calculators in http://www.geocities.com/Athens/Thebes/5118/scicalc/scicalc.htm
- Oliver Schubert's Oli's World of Computer, dedicated to Apple and Atari Computers, in http://homepage.mac.com/olivers/computer.html
- Chris Osburn's pages in http://sliderule.mraiow.com/wiki/Chris_Osburn%27s_Calculating_Instruments
- Hans Bloemen's Museum (also in Dutch and in German) in http://www.calculatormuseum.nl/calc/
- Michael Briley's calculators collection in http://www.phys.uwosh.edu/mike/calcs.html
- Manuals (non HP and TI) can be found from Katherine Wasserman's site in http://www.wass.net/manuals/
- The Wikipedia calculator entry in http://en.wikipedia.org/wiki/Calculator
- A quick start guide to common calculators in http://www.geocities.com/calculatorhelp/index.html
- The Forensic Results (tests about calculator precision) in http://forensics.calcinfo.com/
- The Torture Tests (other tests on calculators) in http://voidware.com/calcs/torturetest.htm
- And of course, in case you print this page, this site of mine in http://it.geocities.com/tonibin/calcs

- From Henry Briggs to Modern Calculators, in http://www.cs.swan.ac.uk/~csharold/calculators/Briggs2calcs.pdf
- Calculators are Needlessly Bad in http://www.uclic.ucl.ac.uk/harold/srf/hucalc.pdf
- A True Calculator in http://www.uclic.ucl.ac.uk/harold/srf/truecalc.pdf
- A New Calculator and Why it is Necessary in http://www.uclic.ucl.ac.uk/harold/srf/allcalcs.pdf

- The main MoHPC pages devoted to slide rules at http://www.hpmuseum.org/sliderul.htm
- Eric's slide rule site at http://www.sliderule.ca/
- Giovanni Breda's collection and notes at http://www.sliderule.it
- Ron Mansley's slide rules site at http://www.sliderules.clara.net/
- The Wikipedia page about slide rules at http://en.wikipedia.org/wiki/Slide_rule
- Dave Van Domelen's slide rules pages at http://www.eyrie.org/~dvandom/slide/index.html
- Dave K's slide rules pages at http://foraker.research.att.com/~davek/slide
- Another site about slide rules (with a very good Java simulator) at http://www.syssrc.com/html/museum/html/sims/javaslide/
- The clever calculator pages at http://www.eminent.demon.co.uk/sliderul.htm
- The Death of the Slide Rule - an article by James Redin - at http://www.xnumber.com/xnumber/hp.htm
- The slide rule as a teaching tool at http://www.geocities.com/Athens/Delphi/5136/slide.html
- Chris Osburn's pages (slide rules and calculators) at http://www.muppetlabs.com/~chris/sliderule/
- Derek's Virtual slide rules gallery at http://www.antiquark.com/sliderule/sim/
- Todd Tolhurst's collection at http://www.toddtolhurst.com/sliderules/
- Make your own circular slide rule with explanations at http://solar.physics.montana.edu/kankel/math/csr.html
- Fredrik's pages about slide rules at http://www.stacken.kth.se/~foo/sliderule/
- The slideruleguy at http://www.slideruleguy.com/
- Giovanni Pastore's pages about slide rules at http://www.giovannipastore.it/index_english.htm
- The history of computing through slide rules at http://trillian.randomstuff.org.uk/~stephen//history/slide-rule.html
- Instructions for a semi-log slide rule at http://calclab.tamu.edu/~fulling/m152/sliderul.html
- Oughtred Society site at http://www.geekculture.com/uplinks/slide.html
- Some history of slide rules at http://www.du.edu/~jcalvert/tech/slidrul.htm
- Macleay Museum slide rules at http://www.usyd.edu.au/macleay/cslipsticks.htm
- Slide rule Online Museum at http://www.joernluetjens.de/sammlungen/rechenschieber/rechenschieber-eng.htm
- Pat Farrel's links and notes about slide rules at http://www.pfarrell.com/misc/sliderule.html
- Going Going Gone about slide rules at http://library.thinkquest.org/3205/Slide.html
- How did a slide rule work? article at http://members.shaw.ca/quadibloc/math/slrint.htm
- MIT meeting about slide rules at http://web.mit.edu/watko/www/slide.html
- University of Alberta page at http://www.engineering.ualberta.ca/uofaengineer/article.cfm?article=22749&issue=22563
- University of Utah page at http://www.math.utah.edu/~pa/sliderules/
- Jim Loy's page about slide rules at http://www.jimloy.com/algebra/slide.htm
- Pilot Balloon Slide Rules notes at http://www.csulb.edu/~mbrenner/slide.htm
- The Rise and Fall of the Slide Rule - Stanford notes at http://events.stanford.edu/events/63/6392/

- Hewlett-Packard in http://www.hp.com/calculators/ (also in http://www.hewlett-packard.com/)
- Casio in http://www.casio.com/products/Calculators_%26_Dictionaries/
- Sharp in http://www.sharpusa.com/products/TypeLanding/0,1056,15,00.html
- Texas Instruments in http://education.ti.com/educationportal/sites/US/productHome/us_product.html
- Canon in http://consumer.usa.canon.com/ir/controller?act=ProductCatIndex2Act&fcategoryid=110
- Citizen in http://www.citizen-systems.co.jp/english/electronic/calculator/scientific_index.html
- Olivetti in http://www.olivetti.com/Site/Public/product.asp?sid=&cid=319
- Kinpo in http://www.kinpo.com.tw/English/calculator.htm (this is the actual manufacturer of many current models of Citizen, HP and other manufacturers!)
- Lexibook in http://www.lexibook.com/product_list.aspx?taf=6&tas=12§ion=1&id_lang=1
- Aurora in http://www.aurora-ltd.co.uk/SubPages/HAN1.htm
- Karce in http://www.karce.com/index_topic.php?did=19684&didpath=/19684 (a Sharp clone?)
- Sentry in http://www.sentryindustries.com/category/calculators/
- Toshiba doesn't seem to produce handheld calculators anymore...