KVARESTO8
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Fairfax Cross County Trail, 41 miles: completed 2 July 2010.
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Category Archives: Computing and Mathematics
The not-so-lost chord
Eliot Van Buskirk sketches the analysis that went into decoding the opening guitar chord of The Beatles’ “A Hard Day’s Night.” He links to an audio clip as well as the detailed paper by Jason I. Brown of Dalhousie University, “Mathematics, Physics, and A Hard Day’s Night.” Seems that the boys had a little help from George Martin on piano.
Short bits of string: 7
After much virtual knuckle-scraping, I have managed to mount the folders from a networked hard drive running Samba from my Windows XP laptop.
Green ears
The FedEx guy left a box at my door yesterday. A Saturday delivery? Yes, indeedy: the XO laptop that I received in exchange for my donation to the One Laptop Per Child project.
The machine is just adorable. If Elle Woods had designed a computer to go with her chihuahua, she would have come up with this (perhaps in pink).
With the help of the getting started guide, I was connected to my wireless network in two shakes, and I was browsing in half a shake more. The web browser is pretty basic, as far as I can tell so far. Bookmarking doesn’t quite work the way we’ve come to expect after 15 years. A positive side effect is that it effectively comes with its own Flashblock. Oops, looks like the New York Times web site just crashed the browser.
The chiclet-y keyboard is is easier than any phone I’ve ever used. My lack of touch-typing skills will serve me well. There’s a little heat dissipated from the back of the screen.
Lots more to play with here, including figuring out what some of the keys do (like the mysterious Hand keys between the Control and Alt analogues). Maybe the games on the XO will entice Leta away from playing FreeCell on my Windows machine.
Becoming reality
Brian Hayes’ XO laptop has arrived.
If the styling has a whiff of Fisher-Price about it, there’s also some thoughtful ingenuity at work here, and designers of machines for grownups might learn something from it.
* * *
The wifi transceiver is amazing. I never knew I had so many well-connected neighbors—people named linksys and netgear, for example. No other computer I’ve had in the house has ever detected any of these networks.
* * *
…the software is just not finished yet. Some basic capabilities (printing, a sleep mode) are not yet implemented, and there are various buttons that don’t yet have functions. The web browser is primitive (no tabs, very limited facilities for bookmarks). There’s an RSS reader that doesn’t seem to work.
The Green 500
Wu-Chun Feng and Kirk W. Cameron of Virginia Tech have initiated a new system of league tables for supercomputers based on energy efficiency, The Green500 List. They introduce the rankings in an article in the December, 2007 issue of Computer. The article abstract:
The performance-at-any-cost design mentality ignores supercomputers’ excessive power consumption and need for heat dissipation and will ultimately limit their performance. Without fundamental change in the design of supercomputing systems, the performance advances common over the past two decades won’t continue.
As the methodology is still new, and requires some apples-to-oranges comparisons, it’s not surprising that the listings are dominated by one vendor’s architecture. IBM’s Blue Gene takes the top 26 spots in the table, with energy consumption of 204 to 357 megaFLOPS per watt. Slot #500 comes in 2 orders of magnitude lower, at 3.65 megaFLOPS per watt.
That which we call a rose
bit-player laments the confusing system of names used to identify complexity classes.
The letter P generally stands for “polynomial” (except where it’s “probabilistic”). N usually denotes “nondeterministic” (but NC is “Nick’s Class”). Likewise the prefix D is for “deterministic” (except that it’s usually omitted, and sometimes it means “difference” or “dynamical” instead). B stands for “bounded-error” (except that BH is “Boolean hierarchy” and “BPd(P)” is “Polynomial Size d-Times-Only Branching Program”). Q is for “quantum” (except “QH” is the “query hierarchy” and “QP” is “quasi-polynomial time”).
The sad truth is, the naming conventions for furniture at Ikea make for a more consistent language than those of complexity theory.
Hmm. Maybe the math and CS guys should talk to the bioinformaticians that gave us Pokemon as the name of an oncogene, until (under threat of legal action) it was renamed Zbtb7.
Lime green
David Pogue reviews a beta version of the XO, the controversial “$100 laptop” device from One Laptop Per Child. As has been reported elsewhere, to help drive down unit costs, a donate-one-get-one program will be in place for a limited time. I’m thinking a solid-state Linux box with web browser would be a cute thing to have around the house. And the tax deduction wouldn’t hurt.
Crooked CA watch: 4
Disgraced former CEO Sanjay Kumar reported to a minimum-security federal prison to begin serving his 12-year sentence.
Crooked CA watch: 3
Stephen Richards, former sales head of CA, has arranged to pay $29 million in restitution.
Crooked CA watch: 2
Wang is wrong: a blistering report by Computer Associates’ board of directors implicates former head Charles Wang as the leader of a pervasive culture of fraud.
Mr. Wang created a “culture of fear” at Computer Associates — now called CA — and deliberately put inexperienced executives in senior positions so that he would have more control, according to the report. He discouraged executives from meeting with each other and arbitrarily fired managers or employees who disagreed with him.
“Fraud pervaded the entire CA organization at every level, and was embedded in CA’s culture, as instilled by Mr. Wang, almost from the company’s inception,” the report said.
How convenient for Wang, who stepped down as chairman in 2002, that the statute of limitations is only five years.
Some links: 14
I’ve started a new blog for profession-related posts, IEFBR14. I doubt that I will devote the same posting volume to it as I do this one.
Digital, not digital
Roland’s crossword puzzle this morning had a reference to chisenbop, a manual reckoning system where you use your fingers like the beads of an abacus. I hadn’t heard about chisenbop for decades, not since I saw a TV ad for a book that would teach your kids how to count on their fingers. I think Fred MacMurray was the celebrity spokesman, but I could be wrong.
And I was thus reminded of Jakow Trachtenberg’s Speed System of doing multiplication and other arithmetic without pencil and paper. Somebody told me about it when I was a kid, I checked the book out of the library and devoured it. I don’t really remember any of it, except that multiplying by 12 was especially easy. Trachtenberg developed the system while he was held in a concentration camp in World War II and, if you will, didn’t have anything better to do with his time. The book is still in print.
The fine line between clever and stupid
Via kottke.org, massively abusing regular expressions and successive divisions by potential factors to determine whether a number is prime in one line of Perl code.
Fearful symmetry: 2
A team led by Jeffrey Adams at the University of Maryland has rendered a map of the gobsmackingly complex E8, a Lie group (sounds like “Lee”). E8 describes the symmetries of a particular 57-dimensional object. A two-dimensional color projection of the map looks remarkably like a mandala.
Short bits of string: 5
Three things that I learned recently:
- Cardboard file boxes (“banker’s boxes”) work very well for costume storage, especially if you have a lot of small pieces that don’t easily hang and that you don’t want to get crushed. We’re storing costumes for 26 cast members in a 3′ x 6′ footprint.
- You can drag and drop tabs in an Excel workbook to reorder your worksheets. I’ve been using the right-click context menu to do that for years. I wonder how many clicks and scrolls I’ve wasted.
- A good articulation warmup is to play Tongue Jeopardy: Sing the “Jeopardy!” theme song, but with your tongue sticking out. On each successive syllable, point your tongue up, left, down, and right. (So you’re actually singing “Anh-anh-anh-anh-anh-anh-annnh…”) It gets really tricky when you get to the eighth notes.
