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Welcome to my personal home page. There are many pages on this site concerning various topics of an entertaining, yet somewhat technical, nature that many visitors should find fascinating.

Recent Updates:

Do you live in Australia? This page explains why you have a unique opportunity to prove that the Earth is not flat, after all.

Having on this site both a page discussing, at length, measurements used by printers and a page going into detail about unit systems used for some typesetting machines, I have finally decided that it would also be appropriate to add a page illustrating the development of typefaces over the years. This brief page goes very quickly over the highlights of the story that can be found in many introductory books about printing.

A page has been added containing a brief chronology of the typewriter, highlighting various technical innovations in its history. Illustrations of some of the kinds of typewriter discussed have now been added. Another thing added, to this page, part of a discussion of extending the capabilities of the Selectric Composer, are samples of text typed on the IBM Executive Typewriter and the IBM Selectric Composer, and even the Vari-Typer, so that the reader can get some idea of their print quality. That discussion continues to, and concludes on, this page, which goes step by step through how I start from the principle of combining the capabilities of an ordinary Selectric typewriter with those of the Selectric Composer in a single machine, and continue by adding features to overcome some of the perceived limitations of the Selectric Composer. The pitfalls one runs into when trying to make a single machine so versatile are exhibited, and in some cases discussed. There is also a new page giving a history of computers in general, and the microcomputer revolution in particular.

At the end of this page, I have appended some comments on the recent 2018 World Chess Championship match between Magnus Carlsen and Fabiano Caruana, as it appears to me the course of that match underscores the need for some action to address the frequency of draws in Chess as it stands.

A page has been added about Triangle Chess, a chess variant played on a board made up of triangular spaces.

A page within the section on Chess in my web site has been updated to note that while the Edinburgh Upright pattern of chessmen may not have been as close to the Staunton pattern as some claim, another style of chessmen, also designed by the firm of John Jaques & Son, now known as Jaques of London, but in 1828, for the Grand Cigar Divan of Simpson's on the Strand, did in fact anticipate almost all of the essential features of the Staunton pattern.

Also, I have added a description of a new chess variant of my own invention to the site, Exciting Chess, which combines Shogi as well as Checkers with Chess. I was inspired to create this variant after also adding a new existing historical variant to my page, The Game of War, which set me to thinking of the impact of having a compulsory capture rule only involving some of the pieces.

A new page has been added to my section on music; its initial purpose is to explain the role of the bass bar and sound post in the design of the violin, but in addition material has been added on the tunings of the members of the violin family along with additional related instruments proposed from time to time, and on various speculations advanced as to what might have been the long sought-for secret of the legendary violin maker Antonio Stradivari.

The page on color filter array designs has been updated to include references to the H6D-100c and the IQ3 100MP medium format camera backs, the Foveon Quattro sensor, and even the Minolta RD-175 camera, also known as the Agfa ActionCam. A recent previous update updated it to include a reference to the Hubble palette, and a slightly less recent one previously described the new X-Trans and EXR designs from Fujifilm.

My page about the components that make up a computer now has a section added at the end about how the packaging of integrated circuits has kept up with the increasing sophistication of microprocessors.

Finally, I have added to this site a page concerning one of the most popular mathematical subjects:

I had long delayed doing so, despite the topic being a natural for this page, as there are many other excellent pages on this subject on the Web. At present, it is quite a modest page on the subject, and I do expect to expand it.

The page about decimal floating-point has been updated to describe the Binary Integer Decimal (BID) alternative format used by Intel computers, and a relatively little-known decimal floating-point format predating the IEEE 754 decimal floating-point standard effort (but not the IEEE 754 standard for binary floating-point) used with the Motorola 68040 microprocessor is also now described on that page.

A brief discussion of perfect forward secrecy, along with the man-in-the-middle attack, has been added to the cryptography pages.

Descriptions of the Rockex, the Hagelin TC-52 and the Gretag TC-53 have now been added to the web site.

A description of the Abwehr SG-39, which was similar to an Enigma, but with a pinwheel assembly controlling the rotor stepping, has been added to the page on relatives of the Enigma, and a description of the SG-41 has been added to the page on Hagelin machines.

My page on keyboard arrangements has had a description of the Neo keyboard, a German-language keyboard designed for more efficient typing, added.

My page of featured images now has an illustration of seven-segment numerals, accompanied by the unusual nine-segment design offered by Itron.

A page about the Korean typewriter has been added to this web site.

A page about modifying the 5-level teleprinter code to enable it to access a larger character repertoire has had added to it, at the bottom, a discussion about ways to modify it so as to mitigate one major objection to the use of 5-level code: the fact that errors in transmission of data can cause garbles when they obscure the current shift state.

My page about the board game Camelot has now had some comments on Reversi, along with some diagrams, added, and also some additional minor notes on the antiquity of the Parker Brothers board game Telka.

A discussion about alternate number bases has been moved from my page on computer arithmetic to a page of its own after some expansion.

A new page has been added featuring puzzles where a 3 by 3 by 3 cube is formed from pieces made up of smaller cubes.

My page about hexagonal Chess variants has had a diagram of the hexagonal Chess variant by Dave McCooey added, and, in addition, a diagram and a description of C'Escacs, an enlarged chess variant inspired by Glinski's hexagonal chess, have been added.

A news item concerning the interest of the government of France in modifying the usual keyboard layout for computers on which data in the French language is entered prompted me to learn more about French-language keyboard layouts. One result is that on this page, where I once referred to a Belgian keyboard layout designed for efficient typing as mysterious, I have now added information about its designer, one Alfred Valley.

A new page describes another hypothetical computer architecture, one which attempts to combine variable-length instructions with signal processor-style VLIW. And since that page was added, another page has been added concerning an attempt to combine an operating mode with CISC-style variable length instuctions with both a RISC architecture and a signal processor VLIW architecture, after closer study of how some real digital signal processors (DSPs) with a VLIW architecture actually worked.

A new page has been added to the section of my site which discusses allowing computers to handle data of a wider selection of lengths than powers of two of a basic unit with no loss of efficiency. This page deals with using the techniques examined in this section to create a highly versatile computer with a native 36-bit word length. And now an additional page has been added on a similar architecture, but with a 32-bit word length, so as to make use of existing memory parts and an existing DEC-TED-S4ED code.

Atranj, a Turkish Great Chess variant, is now discussed here, with particular attention being paid to discussing the move of the Urdabeqin. Also, yet another new chess variant is described on these pages. Drawing from the many previous ones proposed here, it is an attempt to propose a new type of chess set that would have a slight hope of attracting interest, including a 12 by 8 board and pieces for four different variants to suit different tastes.

The rules for Hiashatar, the current Mongolian form of Great Chess, have been revised so that there is enough detail to actually attempt to play a game of it.

Cryptography Entry Page
Index Page

Pencil and Paper SystemsElectrical and Mechanical Cipher MachinesTelecipher MachinesThe Computer EraPublic-Key CryptographyMiscellaneous Topics

Map Projections Entry/Index Page

Cylindrical ProjectionsAzimuthal ProjectionsConic ProjectionsPseudocylindrical and Pseudoconic ProjectionsPolyconic ProjectionsConventional ProjectionsOther Conformal ProjectionsOther Equal-Area ProjectionsMiscellaneous Projections

A brief page with a few annotations about the Girl Genius web comic, for which a link banner appears to the right, is now on this site.


Featured Images

A Short History of Type

Signal Flag Systems
The Vocalization of Hebrew
Introduction to HTML
Color Charts
Building Blocks and the Pythagorean Triangle
Efficient and Flexible Text Encoding
Design for a Tall Building

Movie and TV Aspect Ratios
A Limitation of Color Photography
Color Filter Array Designs

Don't Touch That Dial!
Color Television Madness
Four Speakers from Two Channels?
A Problem in Applied Geometry

Chinese Character Encodings

A Phonemic Alphabet
Two Schemes For Elections
Patterns in Nature and Myth

A Note on Large Numbers
A Unified Architecture for Telephone Numbers
On Philosophy and Ethics


A Brief History of Computers in General, and the Personal Computer in ParticularHow Does A Computer Work?What Computers Are Made FromComputer ArithmeticThe General Layout of a ComputerThe Subroutine CallThe Old Days: Computing Without RAMThe Old Days: Decimal ComputersInterleaved Memory and StridePipelined and Out-of-Order ProcessingClassic VLIWThe Perfect Computer?Minimizing ChangeNot Quite RISCA Historical View of FORTRANRemembering APLComputer Architectural PreferencesComputer Front PanelsThe Punched CardPrint Train TriviaPrinting Terminals and Proportional SpacingDigital Magnetic Tape RecordingReforming ASCII and Unicode

Keyboards Entry/Index Page

Large KeyboardsKeyboards for Genuinely Large Character SetsComments on the Keyboard of the IBM PCKeyboard ArrangementsThe Keyboard Overlay ProblemMaking Keyboards More CompactAn Attempt at a Popular KeyboardScan Codes Demystified


The Slide RuleInfinityArchimedean SolidsPolycube PuzzlesThe Fourth DimensionRotations of a DodecahedronExamples of GroupsTwo Famous EquationsEuler's ConstantSquaring the CircleSphere PackingsGödel's Theorem and the Halting ProblemMagic SquaresThe Mandelbrot FunctionDiophantus at the Printer's ShopChange RingingNotations for FractionsAlternate Number BasesProbability

Tilings Entry/Index Page

The 17 Wallpaper GroupsPentagonal TilingsOctagonal TilingsDodecagonal TilingsHeptagonal Tilings

Chess Entry/Index Page

The Rules of ChessA Little History

A Few OpeningsChess NotationThe Immortal Game (Anderssen-Kieseritzky)The Immortal 50th Game (La Bourdonnais-MacDonnell)

Comments on the RulesThe Crisis in ChessDynamic ScoringA Proposed Rating SystemTournament Tiebreaking

Well-Known Forms of ChessTraditional Enlarged Forms of ChessWarring States ChessThe Game of the Three KingdomsJetan, Barsoom's Game of ChessThe Game of BattleChess-DraughtsHexagonal ChessHexagonal Chess, Part 2Triangular Chess?S. Waider's Chess for Three PlayersEnlarged and Improved ChessFour-Player ChessThe Game of War

Leaping Bat ChessRandom Variant ChessChess 2016Corrected Random Variant ChessOriginal Random Variant ChessThree-Dimensional ChessEngagement ChessFive-Player ChessAn Unusual Board for Three-Player ChessSpectral Realm ChessHalf-Shogi ChessTemporary Marsellais ChessAntimatter Universe ChessAn Ordinary VariantAntimatter Universe Flag ChessYet Another Ordinary VariantRotating Spaceship ChessA Problem CorrectedPrequel ChessReformed ShatranjTwo Off-Centre Ordinary VariantsSnake ChessTomorrow's Chess?Tiebraker ChessExciting Chess

Checkers Entry/Index Page

Two-Move and Three-Move RestrictionsThe Perfect Game [of checkers]?Other Forms of CheckersHasami Shogi, Seega, and Other Related GamesLudus LatrunculorumEnglish Gothic Double Checkers

Board Games

Board Games Other Than ChessA Few Board Games of InterestComments on Wei Ch'i (or Go, or Baduk)Other Uses for a Go BoardThe Greatest Modern Board Game of SkillBackgammonThe Jungle GameRithmomachyThe Perfect [board] Game?Making Wargames More ComplicatedMaking Full Use of Three Ordinary DiceThe World is RoundMaking Board Games More ComplicatedSpace Battles in Three DimensionsThe Real Game of BridgeSiberian Semi-Contract Whist (or Bridge)Bridge for Six: Trivial WhistCounting Tricks Before They're HatchedThe Semi-Tarock Deck

Science Entry/Index Page

A Few Words About StarsA Space Habitat DesignTravel to MarsLining up the PlanetsThe Equation of TimeThe Inconstant MoonThe Einstein-Podolsky-Rosen experimentsThe Fine-Structure ConstantPunctuated Equilibria

Telescopes Entry/Index Page

How a Telescope WorksKinds of TelescopesTelescope MountingsEyepiecesIntroduction to Geometrical Optics

Calendars Entry/Index Page

Perpetual CalendarsA Luni-Solar CalendarA Simplified Calendar ProposalJulian Day NumbersA Martian CalendarA Modest Proposal for the Abolition of the Leap SecondHappy Easter!Happy Hanukkah!The Mayan Calendar

Unit Conversions Unit Conversions

Printer's UnitsTemperature ScalesFrom Gold Coins to Cadmium LightGauge is Not ScaleThe Size of the Piano KeyboardSome Unusual Units of LengthOld Feet and Old PoundsAvoiding the Metric System


The Musical ScaleMore Complicated TemperamentsA Bit About Musical NotationSome Interesting KeyboardsA Bit About ChordsApproximating Equal TemperamentThe Hammond OrganA Minor Mystery: The Chorus Tone GeneratorHow Does a Violin Work?

A Computer Architecture
A Computer Architecture
Entry/Index Page

Memory-Reference InstructionsAdditional InstructionsBasic ArchitectureTagged Operation ModesRestricted FunctionalityOff-Chip Processing

Concertina II
Entry/Index Page

Basic Opcodes

A Computer Language
A Computer Language
Preview Page

Basic InformationWriting an EXALT ProgramArithmetic StatementsControl StructuresType DeclarationStorage ClassesSubprogramsParallel ProcessingUser-Defined TypesProgram Source ModificationExpression EvaluationInput/OutputDatabase ManagementException HandlingAdvanced FeaturesAppendix II: Implementation Notes

Contact Information and Notes

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Copyright (c) 2000, 2001, 2002, 2004, 2005, 2008, 2010, 2011, 2012 John J. G. Savard