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Old May 16th 18, 08:12 PM posted to alt.windows7.general
J. P. Gilliver (John)[_4_]
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Posts: 2,679
Default OT; old CDs and DVDs

In message , Paul
writes:
[]
I've just had a further thought, though: did LightScribe discs have
at least some tracking info on the label side? I'd always assumed
their only difference to non-LightScribe discs was some extra
chemical on the label side. But I got to wondering how the tracking
mechanism was persuaded to work. If it could be constrained to work
in dead-reckoning mode without feedback - after all, the precision
required is at least an order of magnitude less than that required
for the data side - then my idea could work; if the LightScribe
software still needed something to latch onto, then probably not.
(And might explain why "pirate" LightScribe blanks didn't appear, as well.)


You would probably need an index mark of some sort, to
support multiple passes. And to align one "ring" of pixels
with the next. Perhaps this is the "control zone" in the picture ?

http://www.cdrinfo.com/Sections/Revi...13449&PageId=1

Paul

Thanks. "The media ID code can be read on both sides of the media. If a
non LightScribe disc is inserted in a LightScribe drive, it recognizes
the media features and disables LightScribe media." Which suggests - if
non-LightScribe media can be recognised - that the ID code _isn't_
specially written on both sides.

"The control feature zone is used by the burner to control at which spot
it will focus the laser (index mark). This means that if you want to
reprint a disc label, the drive will automatically rotate the disc and
align it to the same point of origin every time and hence will always
print at the same spot as before. So, you can print the same label more
than once on the same disc, to achieve better printing quality." This
suggests you can actually take a disc out to see how the label has come
out, and put it back in for another go: such an "index mark" principle
could then be used with my spray-on coating idea.

"There is no track spiral or other tracking aid." So that's another
reason why my spray-on could work (-:!
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

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