A major revision has been made to the section on A Computer Architecture. This architecture began with several alternate modes of operation, distinguished by differences in the available addressing modes. The number of these modes of operation had increased over time, from about 16 to about 128.
Some time ago, with the introduction of a mode that conserved opcode space using a technique introduced on the SEL 32 computer, operating only on aligned operands in memory, and placing values in the unused least significant bits of address displacements to distinguish between data types, a number of these alternate modes, which were introduced in attempts to allocate opcode space preferentially to various types of instructions as might be most useful in different given types of programs, were obsoleted, and removed, as the result of this introduction.
A further refinement has now been achieved, which has made it appropriate to eliminate the feature of having alternate modes of operation with respect to the decoding of instructions. The addressing modes have been organized in a manner which, in addition to allowing nearly all types of instructions of reasonable frequency to be as short as possible, also organizes the different addressing formats such that determining the length of an instruction, and hence the space it occupies and the beginning of the next instruction, is considerably simplified as to do so no longer requires decoding the instruction completely.
Since this was done, a further relatively minor change has been made. A way was found to reduce the opcode space required for the shift instructions by half using a similar principle, and this has allowed replacing a set of 16-bit instructions for use of the scratchpad registers with a set of 16-bit memory-reference instructions.
While the scheme is not as simple as the original one of the IBM 360 computer (00: 16 bits, 01 or 10: 32 bits, 11: 48 bits) or that of the IBM 1401 computer (where a single bit in each character was used as a marker to indicate where instructions began), the simpification is considerable, and should be sufficient to allow the length of an instruction to be determined in a single cycle even under circumstances of extreme pipelining.
The page on the instruction formats of 16-bit and 32-bit computers now includes an updated chart of the instruction formats of the IBM 360 and its successors, up to and including z/Architecture.
The page about Color Charts now includes a comparison of several different color wheels, including the possibly obscure one of Hilare Hiler.
A page has been added to the section about a perfect computer, noting one way in which it might be practical to design one which would work with standard current memory parts. Also, a modification made has been made to the description of a proposed format for 48-bit floating-point numbers shown on the page about a perfect computer, along with a brief explanation of the rationale behind the precise choice of the length of the exponent field.
The page about the punched card has been extensively modified, with information on a number of older styles of punched cards added.
A new page has been added providing a simple explanation of Einstein's strange theory of Special Relativity.
The page Making Wargames More Complicated now includes one possible way to build a dungeon with random tiles representing sections that allows one basic card type to be used while avoiding dead ends except those intentionally placed on the cards, yet allowing a dungeon with a limited number of entrances. Also recently added is a new image of a grid in which a grid of octagons with small squares in the corners between them alternates with a hexagonal grid; the result is chequered using a somewhat complicated color scheme. As well, a page has been added to the section which it starts specifically addressing how to use three ordinary dice as a substitute for a 20-sided die.
The section on Unit Conversions now includes a page discussing the difficulties in specifying the sizes for the keys on a piano keyboard of standard size and shape, due to an apparent mathematical flaw in its conventional layout. It has also had a proposal for a metric inch of 2.52 centimeters and a metric pound of 453.6 grams, based on the idea that they would allow divisions into thirds (and, fortuitously, sevenths!) in even metric units, much as the day can still be divided into 27 parts which contain an integral number of seconds, the metric unit of time, added to it. Also, a discussion of the standard tournament sizes for boards for a number of different games has been added, as well as a note on the length measures of Barsoom.
The section on the musical scale now includes a mention of the Valotti and Kellner temperaments, as well as a temperament found by the research of Dr. Bradley Lehman.
A brief explanation of the system of vowel points used with Hebrew is given on this page.
I have now had the audacity to begin a page which describes how ASCII could be turned upside down to make the handling of Armenian and certain other languages somewhat more convenient.
The section of featured images now includes a brief mention of the format of player piano rolls.
The section on Aspect Ratios has had a note about and a diagram of the Super 16 and Ultra 16 film formats added.
The page about Keeping the Earth Solar Month in the discussion of a Martian Calendar has been updated with an illustration of a simplified calendar that maintains an approximate correspondence with both the month and the week on Earth.
A description of Rotating Spaceship Chess has been added to the bottom of this page.
A correction has been made to the unit widths for Times Roman on this page; as well, several recent additions have been made to the chart of unit widths: the widths for the Mid-Century face on the IBM Executive typewriter, those for Diablo 630 proportional-spacing printwheels, and the unit widths for several special forms of type made for easier setting of tabular matter by American Type Founders: Self-Spacing Type, Quick-Set Roman, and Typotabular Gothic No. 4.
On this page, I describe a board game which meets a number of desiderata for a board game that I had not previously seen how to fulfill all at once.
I have finally found the moves of the infamous repeated game of the 1863 world championship checkers match between Wyllie and Martins, and have illustrated that game move by move on this page.
A page on the game of Rithmomachy has been added to the site, this topic being a natural for this site, it being a complicated board game of a mathematical bent.
A page to remind people that before both Auction Bridge and Contract Bridge were invented, there really was another game that was called just plain Bridge (the one that is now called Russian Whist to avoid confusion). As well, most noticeably inspired by the Russian game of Vint, on a following page I describe what seems to me to be the next step in the evolution of Bridge, given the pattern of what has gone before: Siberian Semi-Contract Whist (or Bridge). And now I have added a simplified version of Bridge that requires six players.
A new chess variant, Antimatter Universe Chess, is now described wherein conventional chessmen may be used in a game which allows one to drop captured pieces on the board as in Shogi by having players control forces of opposing colors on the secondary board formed by the interior points of the chessboard. As well, a second additional chess variant is described here on this page, and a number of additional combinations have been added to Random Variant Chess.
Major additions have been made to the page about using the roll of three identical ordinary six-siced dice for a greater number of purposes in such applications as role-playing games.
On the page about the games of Chivalry and Camelot, descriptions of the game of King's Court (also known as Supercheckers) and of the Strand War Game have been added. As well, a page about Backgammon has been added.