Charles Petzold



Retirement and Realignment

September 14, 2018
New Jersey

Effective today, I have resigned my employment at Microsoft, concluding an engaging and delightful 4½ years as part of the Xamarin documentation team. I will miss my co-workers immensely, and I hope to keep in touch with them on Facebook.

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“Computer of the Tides” – The Chapter 2 Schematic

May 7, 2017
New York, NY

In the original 1988 edition of his book A Brief History of Time, Stephen Hawking famously revealed why the book contains virtually no mathematics:

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The Dawn of the Sinusoid

April 8, 2017
Roscoe, NY

I’ve been thinking about sine curves recently. The gently undulating pattern of the sinusoid is one of the most familiar mathematical images, but how long has that been the case? Who were the first people to see this curve? Who was the first person to draw it?

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“Computer of the Tides” Chapter 1 (Draft Preview)

December 29, 2016
New York, N.Y.

For over a decade, I’ve been poking away at a book I call Computer of the Tides: Lord Kelvin’s Machine to Disprove Evolution, an extended history of an early analog computer invented by Scottish scientist William Thomson (Lord Kelvin), and its role in the 19th century Darwin Wars.

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Reading Steve Pincus’s “The Heart of the Declaration”

October 30, 2016
New York, N.Y.

I loved Yale historian Steve Pincus’s monumental book 1688: The First Modern Revolution (Yale University Press, 2011). It’s not exactly a primer on the Glorious Revolution; for that purpose, I think a more conventional narrative account such as Tim Harris’s Revolution: The Great Crisis of the British Monarchy, 1685-1720 might be better. But reading Pincus is essential when you think you know the Glorious Revolution and want a fresh look that goes much deeper.

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Reading Margot Lee Shetterly’s “Hidden Figures”

September 19, 2016
New York, N.Y.

For a few optimistic years at the beginning of the 20th century, some people believed that the invention of the airplane had effectively ended war. Air warfare was potentially so horrible and so destructive that no country would dare start a war that might make use of airplanes to invade and bomb from the sky.

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The Metric System for Angles and Time

June 5, 2016
Roscoe, N.Y.

“I often say that when you can measure what you are speaking about and express it in numbers you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind: it may be the beginning of knowledge, but you have scarcely, in your thoughts, advanced to the stage of science, whatever the matter may be.” — William Thomson (Lord Kelvin), 1883.

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The Worst Dental Clinic in New York City?

New York, N.Y.
January 15, 2016

When a dental clinic caters to people with little or no dental insurance, it’s bound to be a mess. But exactly how bad of a mess can it be?

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Writing Xamarin.Forms Apps in F#

November 4, 2015
New York, N.Y.

Judging by the copyright date on some older F# books on my shelf, I think I first started looking at this exciting functional programming language about seven years ago. F# seemed to me to be primarily what I think of as a "crunching" language most suitable for heavy math and database work. For that reason, many of the code examples in these books are console programs. In one of the books, the author needed to draw some graphics, so the F# program creating a Windows Forms window, and used that.

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More Bogus Gun Stats

October 10, 2015
Roscoe, New York

If America truly doesn’t have a gun problem, then why do gun advocates feel compelled to distort gun statistics and even fabricate them? Soon after the recent shootings at Umpqua Community College, one of my Facebook friends demonstrated on which side of the barrel he stands by posting the following graphic:

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De-Obfuscating the Statistics of Mass Shootings

July 5, 2015
Roscoe, N.Y.

After the horrifying killings at the Mother Emanuel African Methodist Episcopal Church in Charleston, South Carolina, President Obama once more had to speak publicly about a mass shooting. "Let’s be clear," he said. "At some point, we as a country will have to reckon with the fact that this type of mass violence does not happen in other advanced countries. It doesn’t happen in other places with this kind of frequency."

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Music Streaming for the Rest of Us

June 18, 2015
Roscoe, N.Y.

Only a company with aspirations to cultural hegemony like Apple could show a video at last week's Worldwide Developers Conference keynote they called “The History of Music” but which contained not a single reference or even allusion to Bach, Handel, Vivaldi, Haydn, Mozart, Beethoven, Schubert, Berlioz, Brahms, Chopin, Verdi, Wagner, Dvorak, Mahler, Debussy, Stravinsky, Bartok, Schoenberg, Berg, Copland, and so forth and et cetera.

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Reading “The Thrilling Adventures of Lovelace and Babbage”

May 25, 2015
Roscoe, New York

Charles Babbage is easily the most annoying person in the history of computing. After conceiving a Difference Engine to compute mathematical tables and create strereotype plates for printing them, and actually getting government funding for the machine, he abandoned that project to design an Analytical Engine that would have been the first general-purpose mechanical computer. Yet, neither project was finished, largely as a result of his failure to finalize design. His eccentric and often irascible personality didn't help matters. His most extensive writings about the Analytical Engine uses it to justify the existence of biblical miracles, and his autobiography devotes a chapter to reprinting a cranky pamphlet he wrote about the evils of street music.

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Drones on Screen and Stage

May 21, 2015

The ability to carry out targeted assassinations using Unmanned Aerial Vehicles (known better as drones) seems like an ideal solution to the problem of combatting terrorism. If a terrorist in a desert of Afghanistan can be identified from the sky, and his body blasted apart with the simple press of a button from a trailer on an Air Force base in the desert of Nevada, then potentially many lives can be saved with the elimination of just one. There is no danger at all to the soldier pushing the button, who can finish off a daily shift and immediately go back home to a loving spouse and kids, with a warm meal around the family table and a comfortable bed.

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Pushback on “The Imitation Game”

January 16, 2015

The current issue of The New York Review of Books includes a review of The Imitation Game by Christian Caryl that pretty much sums up my reservations about the many historical inaccuracies of this movie. Unfortunately, the online version of the review “Saving Alan Turing From His Friends” is restricted to subscribers but an abridgement posted a couple weeks ago, “A Poor Imitation of Alan Turing”, is still available. My recent blog entry “The Imitation Game” and Alan Turing's Real Contribution to Computing discusses the mangling of the mathematics in the movie.

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“The Imitation Game” and Alan Turing’s Real Contribution to Computing

December 11, 2014
New York, N.Y.

As Alan Turing (portrayed by Benedict Cumberbatch) races against the clock to build a machine to crack the Nazi Enigma code in the recent movie The Imitation Game, only Joan Clarke (Keira Knightley) understands the underlying quest of this tortured genius.

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The Infamous Windows “Hello World” Program

December 8, 2014
New York, N.Y.

A recent blog post by consultant John Cook reminded everybody about the infamous "Hello World" programs in the early chapters of the first five editions of Programming Windows:

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My Week at Xamarin Evolve 2014

October 29, 2014
New York, N.Y.

I've been to a lot of developers conferences over the decades, but never before had I been an employee of the company that staged the event. Consequently, it was fascinating getting an inside view of the massive amount of preparation required for Xamarin Evolve 2014, the largest cross-platform mobile developers conference in the world, and just as exciting spending the week at Evolve in Atlanta earlier this month.

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Stop Disseminating Bullshit!

October 26, 2014
New York, N.Y.

If you were browsing periodicals on a newsstand looking for some good informative articles on science issues, is this the newspaper you would select?

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A Computer to Disprove Evolution?

September 15, 2014
New York, N.Y.

If there is an annus mirabilis in the history of digital computing, it is the year 1936 (plus or minus a year or so, and hence technically anni mirabiles). It was in 1936 that Turing published his paper on computability, 1935 that Claude Elwood Shannon wrote his master's thesis that showed the equivalency between switching circuits and Boolean algebra, 1935–38 that Konrad Zuse built his first computer in his parent's apartment in Berlin, 1937 that Howard Aiken presented a concept to IBM that was to become the Harvard Mark I, and also in 1937 that George Stibitz wired up some relays on his kitchen table that added binary numbers and led to the Bell Labs Model 1 Complex Calculator.

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New Book — New Chapter in Life

August 7, 2014
Roscoe, N.Y.

Six months ago I started doing some contracting work for the documentation team at Xamarin — the company that provides tools for developers to write Mac, iOS, and Android apps using C# and .NET. It was a good fit for me. The work experience was so enjoyable that when Xamarin offered me full-time employment, I jumped at the opportunity.

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Reading Elizabeth Kolbert’s “The Sixth Extinction”

August 2, 2014
Roscoe, N.Y.

On one level, this book is a joyous celebration of science. Elizabeth Kolbert is the type of science writer who doesn’t hesitate to travel to exotic and dangerous places where she gets her hands dirty and her feet wet. Readers of this book tag along as the author goes to Panama to look for frogs, hikes through the treacherous terrain in the Southern Uplands of Scotland, swims through the cold waters of the Tyrrhenian Sea, explores a bat cave in the Adirondacks, trudges through the mountain ranges of Peru, snorkels off the coast of One Tree Island at the southern tip of the Great Barrier Reef, and even walks the “pie crust” of the Reef itself.

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Seeing Mieczysław Weinberg’s “The Passenger”

July 16, 2014
Roscoe, N.Y.

The opera begins rather innocently: It is 1960, and we’re on the deck of an English cruise ship. A German couple are sailing to South America. He is a diplomat taking up a new post. She is his loving wife, though somewhat prone to brooding.

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Reading Amir Alexander’s “Infinitesimal”

June 28, 2014
Roscoe, N.Y.

For as long as I can remember, I have been skeptical about the existence of infinity. I just don’t see any evidence of infinity in the real world. The Big Bang caused only a finite amount of matter and energy to come into being, and the amount can actually be estimated. The number of atoms in the universe is about 1080, and while that’s certainly quite a lot, it’s still short of infinite. Since space is defined by these particles, there is no infinite space either.

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