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Re: [Dvdrtools-users] DVD+R/+RW support
From: |
Bryan J . Smith |
Subject: |
Re: [Dvdrtools-users] DVD+R/+RW support |
Date: |
Thu, 24 Mar 2005 18:07:43 -0800 |
Volker Kuhlmann wrote:
From my point of view (home + small business user) I have to disagree. A
quick count of local shops' online catalogs gives:
shop A: 12 different DVD burners listed, not one with -RAM
Are you certain?
9 times out of 10, a consumer drive that also does DVD-RAM is *not*
mentioned as DVD-RAM.
Also, most of the Type 1 DVD-RAM drives are listed under a non-DVD
section.
If they sell LG GSA-4000 series, they do DVD-RAM.
9 out of 10 adds don't even mention it.
shop B: has 2 or 3 iomega DVD-RAM capable burners
It's possible they didn't add -RAM to their feature lists, but neither
sells -RAM media. It's clear that DVD-RAM essentially doesn't feature.
DVD-RAM discs are dold by all media suppliers and CompUSA.
You don't find Macs and Mac software at Best Buy and many of these
catalogs either.
Perhaps in the highly professional area it's different, but even there I
doubt volumes are high.
Again, poor assumption.
DVD-RAM drives sold in such quantity their first year (1997) that the
price dropped from over $1,500 to under $500.
By the time the first DVD-R/RW drives were released, the 3rd Gen
DVD-RAM/R drives were still cheaper due to volume.
Sure, now that DVD-R/RW and DVD+R/RW dominate, I'm sure they are less
popular in comparison.
But the MultiDVD drives that do *all*5* types are still more common than
you think.
DVD-RAM is *not* a commodity consumer format, and it is *never* marketed
as such.
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.
Out of interest I might ring a few more shops next week though.
Ask them if they carry an LG GSA-4000 series or Matsushita or Panasonic
LF-500 series or newer.
If so, it's DVD-RAM.
Come on, that says nothing about its popularity, performance, or
expected time of "being around".
Do you know the first thing about optical archiving?
If not, then there's no way I can convey 12 years of experience.
Before you even bought your first 650MB CD-R (or CD-RW for that matter),
I was archiving to 1.3-2.6GB MO discs.
All DVD-RAM did was finally produce a *standard* for 2.6-9.4GB MO, with
radically improved reliability.
CD-RW, DVD-RW and DVD+RW implement *cheap*, consumer compatible MO.
It is *not* MO designed for long-term back-up.
When consumers have forgotten about DVD-RW and DVD+RW, possibly moved
onto BlueRay or something else, there will be 2 older discs still in
used.
DVD-R(G) WORM and DVD-RAM MO.
Not because of marketing to consumers who upgrade every 1-3 years, but
to archivers who maintain data investments for 15+ years.
DVD-RAM will be around for a long time.
A prediction. Might well come true...
You don't seem to understand the purpose of DVD-RAM.
DVD-RW and DVD+RW are for short-term consumer use.
DVD-RAM was designed for long-term optical archiving.
Before DVD-RW and DVD+RW, heck before even CD-RW, consumers didn't use
anything.
But before DVD-RAM and CD-PD, there *were* optical archivers who had
230, 650 and 1300MB discs per side.
DVD-RAM is a long-term consumer, not a short-term superstore market.
I don't think the issue of long-term backups are all that simple.
Longevity studies of optical media seem to have become rather rare
since the mid/late 90s.
MO is MO.
It does not compare to ROM or WORM, *unless* you enhance it so it
*breaks* consumer player compatibility.
That is exactly DVD-RAM, which it was heavily criticized for, but it
sold because optical archivers adopted it 5 years before consumers like
yourself, because they had already adopted MO 5 years before that.
You seem to be missing this point over and over.
Verbatim has one online for their DVD+R 4x.
Ignore those, they are comparing brands, not technologies.
MO is a stop-gap solution between magnetic and crystal-laser.
The player compatible MOs are not long-term.
Only enhanced MO like many early proprietary MO designs through the
DVD-RAM standard are long-term.
Sony/Philips designed DVD+RW for performance and compatibility, not
longevity.
Ironically, they got the compatibility pretty dead wrong for the first 4
years until the players just improved in MO compatibility.
Pioneer has been WORM from day 1 with DVD-R(A) and now DVD-R(G) for
commodity.
They introduced a consumer MO in DVD-RW, but very few use it, because
DVD-RAM is what you use when you want long-term, non-player MO.
DVD+R MO-hybrid will *never* be as compatible as DVD-R WORM.
This is physical and technical fact.
There are
other solutions too, depending on circumstances. If I have fewer than
say 20 DVDs, I can easily copy them onto new media every 2-3 years, and
the somewhat better consumer DVDs (not talking Princo here) will last
that long.
You obviously want to talk about media brand names and not actual media
technology.
Please go educate yourself *outside* of DVD+RW.
And no, most companies don't want to have to maintain a staff to copy
data every 3 years.
Maybe to test crucial backups, but not to copy.
Especially when standard, consumer MO like DVD-RW or DVD+RW can
introduce a new error just in the copy!
Long-term archiving means 15+ years shelf-life, and verify-integrated
reads/writes.
Do you have any pointers to useful longevity information for any of the
5 DVD formats we've been talking here? I'd be very interested.
Read up on MO in general, and the problems with it.
Then read up on Matsushita/Panasonic Phase-Dual, which was first
introduced in PD-CD and then used for DVD-RAM.
Be warned, 75 percent of "consumer" reviews of think DVD-RAM is a
cartridge and that's why it's different (that's just the Type 1
packaging version).
Oh, I didn't realise that. How does it work? Does the drive handle the
filesystem? Why do you still need udftools then?
You don't need UDFTools at all.
In the early days (circa 2.2/1998), you needed some userspace support.
DVD-RAM comes pre-formatted UDF, but you can format any fs you like:
# mke2fs /dev/hdc
You're not talking about the kernel's packet writing? That would work
with the same steps as above for DVD+RW, and with any filesystem.
Now that DVD+RW support has been added yes, same deal.
DVD-RAM had it back in 1998, before it was expanded to support
non-PD/DVD-RAM.
The problem there is that the performance of Linux udf precludes any
practically usable application (even when ignoring reliability issues).
You seem to keep missing the fact that DVD-RAM isn't so "generic" in MO
nature.
Perhaps it works in the case of very few very big files, but as far as
eg the files in $HOME are concerned, it's not usable. Well that was my
result of an initial speed test on kernel 2.4.~18 anyway. And it wasn't
that easy, documentation was and is non-existant.
With DVD+RW or CD-RW, yes.
DVD-RAM is different.
You lost me here. MO is magneto-optical?, but what are the connotations
of it, ie what other info is "MO" supposed to communicate to me?
CD+RW, DVD-RW and DVD+RW are simple MO implementations.
DVD+R is a MO hybrid, not WORM like CD-R and DVD-R.
DVD-RAM is a reliability enhanced MO.
Do you have any pointers, or even a quick summary?
I'm writing a FAQ/HOWTO myself.
WORM is once-writable here? But there is a DVD+R? I don't understand
you here.
Single-grove WORM, that's CD-R and DVD-R.
From the laser's standpoint, it runs from end-point to end-point, like a
record.
Pie-slice MO does not. That's why CD-RW MO is recorded in "CD-R WORM
emulation mode."
And why it doesn't work with many older drives.
DVD+R has the same problem as CD-RW did.
I'd never use erasable media for long-term, that's why I said "rolling
backups". They'll be good for a few months. Every so often it goes
onto non-erasable media.
But DVD+R is still MO, so just like DVD+RW, you have to worry about
initial write errors.
The *only* commodity MO that does a verify-after-write is DVD-RAM.
And DVD+R WORM?
Doesn't exist.
It is an emulated WORM, using a modified DVD+RW MO disc for a cheaper
price point.
I don't know anyone who gets a silver disk pressed just for a backup,
but then I don't work in the military. For the 4 DVD-+R(W) formats (and
No, there are 3 types:
- Pressed ROM, single-groove
- Recorded WORM, single-groove
- Packet Written MO, pie-slice
From the standpoint of laser movement, the first two are physically the
same.
The latter is completely different.
Or didn't you understand why many CD-ROM drives would read CD-Rs, but
not CD-RWs?
WORM is physically organized like ROM.
MO is not.
--
Bryan J. Smith mailto:address@hidden
Currently Mobile
- Re: [Dvdrtools-users] DVD+R/+RW support, (continued)
Re: [Dvdrtools-users] DVD+R/+RW support, Volker Kuhlmann, 2005/03/24
Re: [Dvdrtools-users] DVD+R/+RW support, Bryan J . Smith, 2005/03/24
Re: [Dvdrtools-users] DVD+R/+RW support,
Bryan J . Smith <=
Re: [Dvdrtools-users] DVD+R/+RW support, Bryan J . Smith, 2005/03/25
Re: [Dvdrtools-users] DVD+R/+RW support, Bryan J . Smith, 2005/03/25