Re: Another bad CD?

On Wed, 5 Jan 2005, Alan Carter wrote:

> Oh, forgot to mention the important bit: the hole is
> very clearly off-centre, by about 1mm.
>
> I think Jim may have a point about the patent thing.
> Since off-centre holes are apparantly a fairly common
> manufacturing defect, they're going to keep occuring
> in the future on discs for which no license has been
> obtained from Sony.  How can anyone tell the
> difference between accidental corruption and
> deliberate corruption?  Does anyone know of a company
> patenting a manufacturing defect before?  If so, what
> happened?

Sony's patent not only puts the hole off centre, it also makes one half of
the disk thicker (by about 0.4 mm) and heavier than the other:

See the drawing linked from the top of the page at:

http://l2.espacenet.com/espacenet/viewer?PN=WO03063154&CY=gb&LG=en&DB=EPD

This thickness change should be detectable (even without a micrometer).

Julian


-- 
Julian T. J. Midgley                       http://www.xenoclast.org/
Cambridge, England.
PGP: BCC7863F FP: 52D9 1750 5721 7E58 C9E1  A7D5 3027 2F2E BCC7 863F