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At 03:28 PM 3/19/2003 -0500, Matt Sohn wrote:
>In January I bought a Plextor 48-24-48 Firewire burner online for a little
>over $200. I'm quite happy with it so far. This brings up a question. With
>the ever increasing speeds of burners, what is the best speed to burn at. I
>have heard that with these faster burners, slow burns are more prone to
>errors, but how fast is too fast? I understand that the Mitsui gold discs
>are only certified to 24X, but is it safe to burn at that high of a speed?

There is no answer to your question except the one that you determine. For
archiving, the question is: How well is the disc written. To determine
that, one cannot rely on reported errors. There are several levels of
quality of write which can be measured beyond simply knowing that a bit
cannot be read correctly after error correction.

For information on the subject, I urge everyone interested in media quality
and measurement to spend some time at Media Sciences, http://www.mscience.com/

In practical terms, one needs a process for estimating the quality of burn
without the extraordinary measures that Media Sciences employs. Whenever I
buy a new supply of media, I burn a few samples at different speeds on the
several drives I use routinely. I then assess the write with one of
Arrowkey's products (Inspector or Diagnostic). My criterion is simple: I
will accept no recoverable errors (and, of course, no unrecoverable ones).

I find with current, quality media I can achieve that goal at 12x regularly
and 8x frequently. If I must write at lower speed, I'm essentially out of
luck since the last media I have which recorded well at that speed passed
their shelf life and were tossed due to excessive errors. (The batches of
media I buy now are small enough so that I am not usually concerned with
shelf life.)

High-speed drives may be able to write perfect discs at lower speeds, but
at full speed are suitable for only casual use. Media Sciences have
information on their inability to qualify drives and media above 16x,
though they have found one medium which satisfies specification in their
test drive at 16x. The problem is not merely the high speed, but the fact
that recording speed varies over the disc. Thus, to write at "48x", much of
the disc will be written at 20-24x, portions at 24-32x, and ultimately a
small part at or near 48x.

Note, too, that "certification" is of little value. Ultimately, it means
that the manufacturer will replace a disc which you can demonstrate failed
because of write speed when you wrote within its limit. To the extent that
replacing the blank - your data are not covered - is meaningful, the
warranty is of value.

Finally (at last), let me note that I run the test above not only on each
batch of new blanks but also on any disc I send out for mastering. In
practical terms, a few recoverable errors are quite acceptable for ordinary
use and may even be acceptable for your archiving, but when I'm spending my
own money to replicate 1-2000 discs, I will spend a few minutes to ensure
that they are correct.


Mike
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http://www.mrichter.com/