Re: cdrtools cdrecord/cdrecord.c
Hi,
> > But why did the [DVD-RW] media work in september 2004 and die a quick
> > and reliable dead in november 2005 ? The same spindles. Two
> > brands with two different media infos. Wether unused previously
> > or re-written.
>
> You'd need a useful error rate scan of the media to establish
> this.
Some lower level ECC mechanisms ?
[sarkasm mode on]
Are there still any error checks left and used with DVD ?
[sarksam mode off]
To my experience (SuSE 9.0, two reader drives), DVD read errors are
not rejected at the drive+driver level but the false data are
happily forwarded to the user process without any error indication.
With CD-RW this is not the case. If a CD-RW fails to verify, then
this is always accompanied by a system error message or at least
an early end of the data stream (experienced with SuSE 6.4 to 9.0).
I use a checksum list which covers 64 kB blocks of the media.
In most cases of DVD-RW failure, it was not applicable, though,
because the media flatly refused to take any data. The checksums
of the previous content still verified, then.
The block checksums were introduced to find out about the
characteristics of young DVD-RW failure. But they are more
useful in evaluating the rare verify problems with DVD+RW
media.
It turned out that if a DVD+RW does not verify a particular
64 kB block on the first try then it usually does it on
the second try or (in two cases) shows a wandering block
error. (Each try is a sequential read of the whole media,
not an immediate retry of the failed block.)
The checksum lists would give me a good chance to recover
from volatile block errors but i do reburn those rare glitches,
rather than putting them on the shelf.
> * Your drive is in fact defective. At first, error correction ...
>
> No-one else reporting this kind of problem lends weight to this being
> the case.
I will learn when this one has passed the way and the next one
gets built in. Currently it works flawless with DVD+RW und CD-RW.
Shrug.
Maybe i should buy some new DVD-RW and test them ... but i am not
eager to pay good money for potentially not-so-well-working media.
Maybe i should buy a new burner ... but that would reward the
industry for selling poorly tested hardware.
Shrug again. Let's burn a little backup for relaxation ... :))
> * Your drive has deteriorated, put sloppily, is worn now. How many DVDs
> did you burn in it in its lifetime? Give us a number.
769. (No pun. They get logged.)
> friend of mine established for a CD burner that its life lasts 300-400
> burns, then it's become so slack, it doesn't meet quality control any
> more.
Obviously i have more luck with burner longevity.
Since january 2003 there were 2109 CDs. Mostly -RW.
The LG DVD burner did about 700 of them (since summer
2004).
No signs of weakness with CD-RW or CD-R.
The LITE-ON CD-RW which did the previous 1400 CDs is
still working fine, too.
> * The media you tried is of short-lived quality.
At least that special combination of burner and media
seems to be.
I came to the decision that they just don't like each other
and that this relationship got a bit deeper over the time.
Have a nice day :)
Thomas
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