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Play GNU Chess On Your Scanner
leighklotz writes "Debian developer and Internet Mail Archive founder Jeff Breidenbach of PARC has made GlyphChess, a chess-playing
copier using Python, GNU Chess and DataGlyphs attached to
the bottom of the pieces. DataGlyphs are cool 2D barcodes made out of / and \ marks for ones and
zeros that use the coding from CDs for error coding. If you don't happen to have a Xerox machine at home, it also works with SANE..."
And the "Most pointless thing ever" award goes to...
How do you undo a move, tear up the last page of paper?
Trolling is a art,
Do you get to send the winner a photocopy of your ass when you lose?
I have often regretted my speech, never my silence.
-Xenocrates
The Ubiquitous Reed-Solomon Codes
by Barry A. Cipra
Reprinted from SIAM News, Volume 26-1, January 1993
In this so-called Age of Information, no one need be reminded of the importance not only of speed but also of accuracy in the storage, retrieval, and transmission of data. It's more than a question of "Garbage In, Garbage Out." Machines do make errors, and their non-man-made mistakes can turn otherwise flawless programming into worthless, even dangerous, trash. Just as architects design buildings that will remain standing even through an earthquake, their computer counterparts have come up with sophisticated techniques capable of counteracting the digital manifestations of Murphy's Law.
What many might be unaware of, though, is the significance, in all this modern technology, of a five-page paper that appeared in 1960 in the Journal of the Society for Industrial and Applied Mathematics. The paper, "Polynomial Codes over Certain Finite Fields," by Irving S. Reed and Gustave Solomon, then staff members at MIT's Lincoln Laboratory, introduced ideas that form the core of current error-correcting techniques for everything from computer hard disk drives to CD players. Reed-Solomon codes (plus a lot of engineering wizardry, of course) made possible the stunning pictures of the outer planets sent back by Voyager II. They make it possible to scratch a compact disc and still enjoy the music. And in the not-too-distant future, they will enable the profitmongers of cable television to squeeze more than 500 channels into their systems, making a vast wasteland vaster yet.
"When you talk about CD players and digital audio tape and now digital television, and various other digital imaging systems that are coming--all of those need Reed-Solomon [codes] as an integral part of the system," says Robert McEliece, a coding theorist in the electrical engineering department at Caltech.
Why? Because digital information, virtually by definition, consists of strings of "bits"--0s and 1s--and a physical device, no matter how capably manufactured, may occasionally confuse the two. Voyager II, for example, was transmitting data at incredibly low power--barely a whisper--over tens of millions of miles. Disk drives pack data so densely that a read/write head can (almost) be excused if it can't tell where one bit stops and the next one (or zero) begins. Careful engineering can reduce the error rate to what may sound like a negligible level--the industry standard for hard disk drives is 1 in 10 billion--but given the volume of information processing done these days, that "negligible" level is an invitation to daily disaster. Error-correcting codes are a kind of safety net--mathematical insurance against the vagaries of an imperfect material world.
The key to error correction is redundancy. Indeed, the simplest error-correcting code is simply to repeat everything several times. If, for example, you anticipate no more than one error to occur in transmission, then repeating each bit three times and using "majority vote" at the receiving end will guarantee that the message is heard correctly (e.g., 111 000 011 111 will be correctly heard as 1011). In general, n errors can be compensated for by repeating things 2n + 1 times.
But that kind of brute-force error correction would defeat the purpose of high-speed, high-density information processing. One would prefer an approach that adds only a few extra bits to a given message. Of course, as Mick Jagger reminds us, you can't always get what you want--but if you try, sometimes, you just might find you get what you need. The success of Reed-Solomon codes bears that out.
In 1960, the theory of error-correcting codes was only about a decade old. The basic theory of reliable digital communication had been set forth by Claude Shannon in the late 1940s. At the same time, Richard Hamming introduced an elegant approach to single-error correction and double-error detection. Through the 1950s, a number of researchers began experimenting with a variety of error
I don't need no instructions to know how to rock!!!!
Amazingly enough, it's possible to play chess using these strange "pieces" and a "board." Although the idea is novel i suppose.
- tristan
Clearly, they're running their web server from the copier, too. Paper jam!
"PC Load Letter"? WTF does that mean?
DataGlyph techology is patented by the Xerox corporation. The DataGlyph toolkit is a binary only library that you must license to include with your "product". Despite the use of Python and GNU Chess in this example, I doubt very much that DataGlyphs are going to be of much use to the open source community.
I can run Duke Nukem on a Cue Cat.
I don't need no instructions to know how to rock!!!!
No, let's play global thermonuclear war.
Beauty is in the eye of the beerholder.