ok, about microscope data,
i've gave up on matlab... can't convert them to binary images -
ther's too much noise, or i suck @matlab, so i've cut out fragments and converted them to grayscale
>full images are here<
(they cover much larger scale and are uncompressed, so if you find this interesting,
please download this archive instead.)
so i've asked professor from local university, could i take a look at cd with optical microscope
that they have there (Nikon ECLIPSE L150)
and he said ok, and actually was very kind and did most himself, i only got to click mouse few times
this is how data loolks x800, near the edge of datatrack. (tracks go verticaly at slight angle)
transition area from data to ring x800
background x800
block, that form letter pattern x800 (it's out of focus and looks like toning in plastic, but no - it isn't)
upper right corner of the same block x2000
zoom in x4000
so it certainly does look like the transition area is empty.
background really is $59 (01011001 |EFM> 10000000000100)
Code: Select all
1000000000010010010000000000100100
___________---___-----------___---
-----------___---___________---___
11T 3T 3T 11T
if there is 11T-6T-11T in bg pattern - it's much more rare, but i could not find one.
(on these photos, i only was for about an hour at microscope so this is all i got)
logo really is made of $A8 (10101000 |EFM> 01001001001001)
Code: Select all
0100100100100100001001001001001000
_---___---___-----___---___---____
-___---___---_____---___---___----
3T 5T
dsv looks unmanipulated, i think, because on one track same bit can be set with pit->land and
on the other with land->pit change (hece the chessboard look of background).
it's a good thing, i guess.
also i guess this means - every cd would form a bit different drawing - large elements would be the same,
but pit land sequences would be often inverted, because of unique subcode.
on 5th image (pattern x2000), in the upper right corner it does look like T11-T11 sync pattern. so it probably
sync bytes also form radial structures of their own, going across whole ring.
this precision, how one byte ends up atop another on neighboring tracks - this is what's scarry.
i'm not sure how it's happening on cd-r/rw.
it would be interesting to burn ring or just some sequences of $59 and $a8 and take a look on microscope -
how they align, it could be sega's machine manipulated lenght of pits/lands to achive this, but it's a guess.
also, probably it's all meaningless and the last check is not on photos at all. maybe it's something else?
but it's a guess again.
it's, because while taking photos there were actually some spots on plastic, that i thought were a dust but professor,
he was very sure, it isn't. he said it's inside plastic (could be toning). at those places pits looked slightly darker
and out of focuss.
they were round and uniform and about where logo goes (with size of around half of pattern forming block x800),
and i think there was none @segment, without log - wher's just background.
but it's most probably just a fault in production or aging effect. i've found very similar images here: [figure3]
http://www.andraste.org/discfault/discfault.htm
also RPS said something about area with no EFM, and hologram only being used for tracking. and it looks like
he was right about pre-ring, would it be toned plastic - it could probably work, i guess. but to be honest -
i don't quite understand what he said, and am probably missinterpreting.
so anyway, it would be very, very interesting if somebody could examine another cd and confir this true or false.
so if someone can get to microscope at university or lab, please try, ok?
it's probably enought with about x600.
).
)