Re: [Dvdrtools-users] DVD+R/+RW support

[Volker Kuhlmann]

> 9 times out of 10, a consumer drive that also does DVD-RAM is *not* 
> mentioned as DVD-RAM.

As I said, the count is from the online product feature list. More
reliably one would look up the manufaturers specs, but that's gonna kill
half a day (most websites should be indented 6 feet and covered with
dirt) so I postponed it for later.

> If they sell LG GSA-4000 series, they do DVD-RAM.

How well does that line do the 4 consumer formats +-R(W)?

> But the MultiDVD drives that do *all*5* types are still more common than 
> you think.

That's good news, I'll look out for one next time I upgrade.

> But you were talking backup, and DVD-RAM is the king, and *no*one*, not 
> even Sony/Philips themselves, can debate the reliability of DVD-RAM for 
> backup versus DVD-RW and DVD+RW.

Ok, but that still doesn't mean every backup job needs 15+ years
longevity. My personal ones don't - by the time I have assembled a dozen
CDs which I want to keep permanently, I'm more than happy to copy them
to DVD for the convenience factor of a reduced number of disks. By the
time I have a dozen DVDs, ...  A lot of business backup jobs are pretty
short term too.

> Ask them if they carry an LG GSA-4000 series or Matsushita or Panasonic 
> LF-500 series or newer.

Telling about the local popularity would be if I asked for a DVD-RAM
burner...  But thanks for the model tips.

> CD-RW, DVD-RW and DVD+RW implement *cheap*, consumer compatible MO.
> It is *not* MO designed for long-term back-up.

Yes, I had already said I wouldn't use it for long term. For up to a few
months though it's very convenient, and I've not had failures
personally. For up to a few years, the consumer formats are good enough.
Above that I'm happy to take your experience and knowledge for DVD-RAM
being the way to go.

> Pioneer has been WORM from day 1 with DVD-R(A) and now DVD-R(G) for 
> commodity.

What is (A) and (G)?

> With DVD+RW or CD-RW, yes.
> DVD-RAM is different.

Let's forget about CDs here for a moment. DVD+RW allows to be used as
random access device the same as a hard disk. It requires kernel patches
which aren't typically included by vendors. Mandrake tried about a year
ago to include the kernel patch and killed a lot of peoples' cdrom (or
dvdrom) drives because some dipshit decided to make drives which reuse a
burn command for a reflash-firmware command (was it LG?). I did get it
to go, but it's a dead duck under Linux for 2 reasons: Linux udffs
creates far too many head movements and block rewrites when writing, and
the kernel uses every spare bit of RAM for write buffering thus killing
the computer for any other use. That holds for all 2.4 kernels, the same
effect can be observed with large flash-memory based storage devices.
2.6 kernels are probably better (I should try again), but patching block
device writing isn't everyone's ballgame for production systems.

How is DVD-RAM different for a Linux user? If it behaves likewise like a
random access hard disk, the kernel's udffs would be used for writing,
with the same drawbacks as mentioned above. I can't see the write
buffering being different. And it does work with a stock Red Hat 7
kernel without further kernel patching? I didn't think this is possible.
How/why does it work?

> I'm writing a FAQ/HOWTO myself.

Niiice, is it online yet?

Thanks,

Volker

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Volker Kuhlmann                 is possibly list0570 with the domain in header
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