On my page about large keyboards, I've accompanied
the existing diagram of the Space Cadet keyboard by one of the Knight keyboard and one of the
SAIL keyboard which preceded it, and I have also included a diagram of the keyboard of the
9210 Scientific Descriptive Printer, which was used for preparing programs in COLASL to run
on the IBM STRETCH computer (the prototype of the IBM 7030). As well, on my
page commenting on the keyboards for the IBM PC, I've added diagrams of the keyboards for the
SANYO MBC-550 computer, the Spectravideo SV-328, and the Fortune Systems 32:16, as well as replacing
the small diagram of the keyboard of the Radio Shack Model II computer with a larger one.
I have added a brief page about hyperbolic
trig functions and the Gudermannian. In addition, in the page about
special scales in the section on slide rules, I have fleshed out the description of the
scales of the Hemmi 153 slide rule, as well as adding information about the Flying Fish 1018
slide rule. As well, in the course of other minor corrections and additions to my pages on
the slide rule, on the final page of that section, I have
(finally!) added a diagram and an explanation to help provide a deeper understanding of
how a slide rule works and is designed, by explaining how the manipulations involved
in multiplying a series of numbers, and the way the cursor works, create a fundamental
distinction between the sliding portion of the slide rule, and the stock within which
On this page, I've finally added a diagram and some text in which
I acknowledge some new developments in amateur astronomy: Meade's Advanced Coma Free telescope, Celestron's EdgeHD telescope
and their Rowe-Ackermann telescope, as well as the Hyperstar accessory from Starizona.
Just in time for Halloween! In my section on ways to handle 36-bit, 48-bit, and 60-bit data in a world
built around the 8-bit byte and the 32-bit word, I have now added the page Triskaidekaphobia
which considers using 60 bits out of every 64 bits to provide five 12-bit storage units from every 64 bits of memory...
and then turning around and making four out of every five of those storage units, in effect, 13 bits long. Since not all of
them have that extra bit, limitations are imposed on the EQUIVALENCE statement which, if disregarded, could lead to some...
interesting... program bugs. So it could lead programmers to think of the thirteenth bit as unlucky, hence the title.
The section of featured images now includes a brief mention of
On a new page in the mathematics section, I discuss
Bayesian Statistics and the Doomsday Argument.
After a long period of inactivity, my pages on Map Projections have,
as their first addition of the current new series, a page concerning the conformal projection
of the world on an ellipse! And (without waiting to complete the project of updating my own BASIC
program to draw this one as well) I have also added on the following
page the Adams-Cahill conformal projection of the world on the surface of an octahedron
by means of the Dixon elliptic functions. Since then, another five pages have been added:
one on the new Equal Earth projection, one on the
Boggs Eumorphic projection, one on the
Strebe projection, and one on
perspective projections, as well as the page noted in
the paragraph below on the Dietrich-Kitada projection.
Additions have also been made to several
other pages, including the ones about the Mercator projection,
the Bonne projection,
the Mollweide projection,
the Hammer-Aitoff projection,
Lambert's Conformal Conic projection, and even
the Winkel Tripel projection. Possibly of particular interest,
my page on the Ginzburg Projection now has coverage of the closely
related Latitudinally Equal Differential Polyconic Projection, widely used for world maps
in the People's Republic of China.
And now I have perhaps made the most exciting addition to the section on map
projections yet. Many years ago, at the library specializing in maps at the University I attended,
I noticed an old German book with a lot of maps in an unusual projection I hadn't seen before.
It stuck in my mind. Eventually, I learned about the Van der Grinten IV projection, and assumed that
this was the map projection I had seen so long ago. But I learned that I was mistaken. A
by a noted cartographer, on the web site of his company, noted that one Bruno Dietrich wrote an
unusual book with many thematic maps in a novel map projection, not described, and years later,
a Japanese cartographer, Kozo Kitada, assuming the projection was equal-area, as it appeared to be,
worked out what the construction of the projection must have been. The forum post described enough of
its properties that I was able, particularly with the aid of maps on-line in that projection to let me
see what I was aiming at, to also work out how that projection would have had to work.
So my site now has a page on what that map projection really was - it turns out that instead of being
a conventional projection like the Van der Grinten IV, it was equal-area - and (after a difficult
debugging session) I got my little BASIC map-drawing program to handle that projection (it may be
the second map-drawing program in existence that does so), so now I
present my web page about the Dietrich-Kitada projection.
Do you live in Australia? This page explains why
you have a unique opportunity to prove that the Earth is not flat, after all. UPDATE: A note has
now been added to show that Flat Earth believers might still have a possible fall-back position
available to them.
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.
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.