[Old Index Page] [Latest Additions]

Search this site:

Custom Search

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:

A page has been added containing a brief chronology of the typewriter, highlighting various technical innovations in its history. There is also a new page giving a history of computers in general, and the microcomputer revolution in particular.

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 page on color filter array designs has been updated to include a reference to the Hubble palette. A recent previous update described the new X-Trans and EXR designs from Fujifilm.

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

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 ConstantSphere PackingsGödel's Theorem and the Halting ProblemMagic SquaresThe Mandelbrot FunctionDiophantus at the Printer's ShopChange RingingNotations for FractionsAlternate Number Bases

Tilings Entry/Index Page

The 17 Wallpaper GroupsPentagonal TilingsOctagonal TilingsDodecagonal TilingsHeptagonal Tilings

Chess Entry/Index Page

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 2S. Waider's Chess for Three PlayersEnlarged and Improved ChessFour-Player Chess

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?

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 Generator

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 OpcodesRegister Arithmetic

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

Privacy Notice

These pages now include advertisements. These advertisements make use of a cookie to serve advertisements based on your interests. You may disable this by visiting this web page.

Needless to say, any trademarks referenced are the property of their respective owners, and are used here only for purposes of identification.

This site is not approved by, sponsored by or affiliated with either Studio Foglio LLC, Airship Entertainment, Phil and Kaja Foglio, or any other present or future assignee of the rights to the creative works of Phil and Kaja Foglio.

Girl Genius is a registered trademark of Studio Foglio LLC. Agatha Heterodyne, Moxana, and the Silverodeon and all Girl Genius art, characters, design elements, logos, and related indicia are trademarks of, and copyrighted by, Studio Foglio LLC. The link banner above, containing items among those listed, is used by permission.

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