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to read a stone dvd


Re:Presumably... (Score:5, Interesting)
by QuoteMstr (55051) <dan.colascione@gmail.com> on Thursday November 12, @10:42PM (#30083230)

There are some ancient writings which no one knows how to read anymore. Will future archaeologists wonder what the microscopic pits in our coasters with holes in them are all about?

That's an interesting thought experiment. Let's say civilization fell and rose again, and that future archaeologists came across some of our optical discs. They wouldn't need much beyond 19th-century technology and mathematics to decipher them.

Once cleaned, 1,000-year-old discs would still shimmer the way they do today. Under a microscope (well-developed by the 19th century), pits and lands would be visible. A pit [freepatentsonline.com] is approximately the same size as a bacterial cell [wikipedia.org], after all. The pits and lands would form a recognizable pattern. That pattern looks nothing like binary, being a clocked encoding [wikipedia.org] of it. But it's obvious that a CD would spin, so eventually someone clever will realize that information is encoded at clock boundaries.

That having been figured out, these future archaeologists will see repeating patterns of eight units. Presuming that our language came down intact (much like Latin has to us), 19th century cryptanalytical [wikipedia.org] techniques could determine the correspondence of the mysterious 8-pit repeating units to letters. (After all, what is ASCII except a simple substitution cipher?)

ECC information would be gibberish, but it could be ignored. (And once even one Wikipedia backup were deciphered, the ECC information would be understood.)

Of course, there's a huge amount of information on each disc. It'd take a long time to go over even part of one by hand, but it could be done. After all, even in the 17th century, huge logarithm table [wikipedia.org] books were produced.

Once technology advanced a bit, it'd be possible to build an electromechanical system to read and print the contents of CDs. Even Babbage had a workable printer design [bbc.co.uk], and printing telegraph machines emerged by 1910. The hardest part for our future archaeologists would be reading the discs at high speed, for which (I think) they'd need a laser. But maybe the problem would stimulate them, and they'd build lasers before we got around to discovering the things.

Of course, this is just idle speculation, but it's fun!