On Thu, 21 Jun 2007 09:14:41 +0100, Jim Lesurf
wrote:

In article , Arny
Krueger
wrote:
"Jim Lesurf" wrote in message



IIUC The BluRay system differs from both standard DVD and HD-DVD in
locating the information layer much closer to the disc surface. Just
100 microns below the read surface, rather than around 600 for other
discs.

IME the most common kind of scratching that puts an end to the
usefulness of a DVD does not come from the read surface side, but from
the label side.

That may be so. I've not encountered any problems with DVD as yet. In
general, it seems to me to be physically about as robust as CD.

However IIUC with DVD the information layers are roughly half-way though
the disc - i.e. about 500 to 600 microns from either surface. But with
BluRay they are only around 100 microns from the playing surface, and over
a mm from the label surface. Thus I am wary of assuming that BluRay will
behave as DVD in terms of vulnerability to scratches or dirt.

Slainte,

Jim

The Blu Ray layer format is described, a little simply, here

http://www.pctechguide.com/34DVD_Blu-ray_Disc.htm

HD DVD is here

http://www.dvdorchard.com.au/images/Hddvd_details.gif

d
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