quality of writeable optical media (was Re: SCSI CD drive capable of reading CD-R)

[Eric Smith]

Billy wrote:
> 3.  The major differences in media came from the dye and the process to
> deposit the dye.

And the composition, thickness and uniformity of the reflective layer,
and the tolerance of the centering (spiral center vs. spindle hole
center), and the wear of the stamper, and a myriad of other
characteristics.  The Red Book and Orange Book have a huge list of
parameters and their allowable ranges, and any one of them screwed up
will yield unreliable media.  It's not just the dye and deposition
process by a long shot.

What you're saying about recent writable DVD media is not unlike
how the situation used to be with writable CD media.  But there *are*
a lot more manufacturers of writeable CDs now.  Maybe there aren't
many sources of bare polycarbonate discs, but everything else in the
process is done by many vendors.

> Thus, most CD-Rs and DVD+/-Rs come from a small number of physical
> plants.  In 2000, you could count them on one hand.  Since then, they
> may have doubled.

For CD-R and CD-RW, it has far more than doubled.

> There ARE some really crappy disks coming out of China - I've seen some
> I could read a newspaper through.  [...] But with rare exceptions, these
> disks never reach the US or Europe.

Rare, my ass!  In six different stores in three different major
US cities I have had no trouble spotting multiple brands of that crap.
It's routinely advertised as store specials in the local newspapers.
Usually with "no returns" in fine print.

Lots of the stuff *does* make it to the US, precisely because there
isn't any accountability for it.  If you have a bad disc (or a bad
spindle), who are you going to complain to?  Stores buy it because
they know there are gullible customers they can flog it off to.

> 5.  Saying a certain brand is crap, and another outstanding may be only
> a personal bias.

No.  Saying that media from CMC Magnetics is crap is a statement of fact,
backed up by much evidence collected over a period of years.  CMC Magnetics
discs purchased last month were not any better than those purchased
three years ago.

> If you have personal preferences that lead you to pick one brand over
> another, go with it,  But base your decision on the results of YOUR
> drive with YOUR media.

Multiple sources of CMC Magnetics media tested on thirteen different
drives from multiple vendors and of different generations from 1994
through 2005.  The CMC Magnetics discs are just crap, pure and simple.

   Readers:  Toshiba, TDK, Teac, Philips, Sony, Plextor

   Burners:  Yamaha, Plextor, Toshiba, TDK, Liteon, Sony, Plextor

Also, the fact that TDK has at times in the past shipped CMC Magnetics
media under the TDK brand does tell me something very important about
the TDK brand.  Even though TDK might not be shipping CMC Magnetics
media today, there's no way in hell I'll ever buy writable optical media
from TDK again.  Not because it's crap today; since I haven't tried it
recently I don't know.  But instead, because it is proof positive that
TDK does not perform adequate qualification of their suppliers.  Thus
there is no way to buy TDK optical media and have any reasonable
expectation that it is not crap.

Eric