quality of writeable optical media (was Re: SCSI CD drive capable of reading CD-R)
bpettit at ix.netcom.com
Mon Apr 18 22:48:54 CDT 2005
> 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.
Of course I simplified to keep this at a reasonable length. There are
dozens of parameters requiring control to make readable media. But the
major one that differs by brands from the same factory is dye formula.
Most of the other parameters would be the same.
One key your didn't mention is hardness and scratches. But the
parameters you did mentioned ARE controlled by the tolerances in the
Red/Orange/White etc books. If the witness disks don't meet the
standard, the license could be pulled. These parameters have to be in
control to qualify for carrying the logo. More importantly, they have
to be in control to go into high volume production and get decent
yields. Without tight quality, a factory can't meet its own numbers.
> 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.
I think we may be talking apples and oranges. I'm refering to high
volume plants - 100+ million units a year. The last industry survey I
saw showed only 8 such plants.
> 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.>
Again, the factories and media I'm talking about are mainland China.
They don't make it to the US because among other reasons, they don't pay
the license fees. The Optical Storage forums watch very closely. As
soon as they spot one, they head straight to Customs and plug it. Lots
of cooperation these days from Customs given the current political
I'm not certain what brand names you are talking about. Two that are
showing up in Silicon Valley but aren't very good are GQ and
kHypermedia. Are these who you mean?
> 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.
For my personal use, I've had no problem taking a spindle back if I get
a coaster. Both CompUSA and Fry's have stood behind their sales. Best
Buy - I've never had a bad disk.
Until I retired, I bought 1.5-2K work disks a month, most through dummy
accounts. The people I dealt with were always willing to give a refund.
> 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.
I just looked at my test numbers from 2002-2004, and I don't see the
problems you describe. CMC is not at the top of the list, but neither
is close to the bottom. And the tolerances are tighter on more recent
> 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
I've tested all those units, though mainly with Philips. Again, my data
doesn't match yours. I'm especially surprised that you had burn problems
with the Yamaha drive. They are by far the most roboust unit of those
> 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.
This is where I cannot agree with you. At Quantum, I had an opportunity
to visit TDK head and magnetic media factories in Japan and China. I
also took customers with me and they went through the Quality processes
of TDK with a fine tooth comb. TDK has a world class quality organization.
Later I tested their optical drives and media. Their quality is some of
the best in the field. I just looked at the numbers on my DVD Recorder.
In the last 18 months, I've used 1200+ DVD+R disks. About 250 of
those were TDK. I had 2 bad burns, both just before I lost an OPU. The
only other media that I've better luck with is Sony (who doesn't make
their own anyway).
Look, I'm not trying to change your opinion. You don't like CMC and TDK
and feel you have results to prove your case. That is what I was
suggesting people should do.
My own data doesn't match yours. I don't agree with your conclusions
about CMC or TDK. So what? You should buy what you like. I'll buy
what I'm comfortable with. I've had good experiences with both. When
the price is right, I'll buy them again.
Interestingly, I just recieved an eMail with a long complaint about
Memorex and how they've never made a good recordable media, DVD or CD.
Yet Memorex usually came out high on our testing.
By the way I'm curious, what software did you use for this testing -
Roxio, Mediostream, Nero, Neo, Pinnacle, Sonic? This is one area where
you can get widely divergent results from the same batch of media.
More information about the cctalk