[CentOS] DVD writer problem

[Bryan J. Smith]

Oh man, where should I begin?  I'm going to top-post, because there's
just a lot of things to know.  I really need to make a HOWTO (as people
on the DVDRTools have been asking).

I could really "go in deep" on all the record/rewrite formats, because
they are pretty different.  For right now, let's assume you are using
DVD-R.

In a nutshell, there are 3 major types of drive firmwares:  
 - Matsushita (DVD Consortium)
 - Pioneer (DVD Consortium)
 - Sony/Philips (DVD+RW Consortium)

Even though there are dual-format and even multi-format burners these
days, there are different types of firmware supported by different types
of drives.

Pioneer firmware pretty much works with any of the following "linear,
character-by-character record" programs:
 1.  cdrecord-ProDVD (Jorg's official DVD recording program, non-GPL)
 2.  dvdrecord (a fork of an earlier CDRecord release, GPL)
 3.  cdrecord+DVDpatch (CDRecord 2.0 + DVD drive support strings)

Matsushita drives are a little different, typically only work with #1,
maybe #3.  #3 typically comes with most newer distros (much to Jorg's
dislike, because the package is still called "cdrecord").

Most other DVD Consortium drives seem to be either Matsushita or Pioneer
firmware-based, some are actually both.  E.g., the LG GSA-4000 series
actually support both, and _all_ DVD formats (DVD-RAM/R/RW+R+RW).

Sony/Philips firmware is a bit different, designed around the features
(and limitations) non-DVD Consortium DVD+RW format.  So while newer
drives support dual-format, they don't support all the modes.  It seems
only Jorg's cdrecord-proDVD is capable of driving them.

*BUT* you don't have to use a "linear, character-by-character record"
program.  Yes, the most "consumer compatible" way to record a DVD-R is
to do so in "disc-at-once" (DAO) mode so the laser is never turned off
from beginning to end (it's also mutually exclusive with burn-proof),
which is something that Sony/Philips firmware don't support (at least
not until more recently).

Hence why the "dvd+rwtools" tools were created.  In a nutshell they
allow direct block access to the disc, instead of using a linear record.
The reasons for this have to do with the fact that DVD+RW (which DVD+R
is based on) drives weren't designed single-groove recording like DVD-R
drives (note, DVD-RW works completely different than DVD-R), because
there are inherit limitations and disadvantages with "linear, character-
by-character record" (the only real positive if legacy consumer player
compatibility).

So if you're recording DVD+R on a Sony/Philips drive, you want to use
"dvd+rwtools."  If you're recording DVD-R on a Pioneer/Matsushita drive,
you want to use either cdrecord-ProDVD or cdrecord+DVDpatch.  If you're
swapping the two (DVD-R on S/P, DVD+R on P/M), they you might be able to
use newer versions of the programs and it will work, it depends.

There's a lot of history in the formats, and the drives were designed
from different viewpoints.

Pioneer, clearly for consumer player compatibility (DVD-R, DVD-RW more
of an "afterthought" and not very well designed).  Matsushita, clearly
as an optical data archiving drive (DVD-RAM is the ultimate in
reliability and longevity, but very, very slow and not consumer player
compatible).  Sony/Philips, clearly a high-performance MO drive, and
attempted to beat Pioneer to market on a lot of things (but never did
prior to dual-layer).

-- Bryan

More info (not to enough depth, hence why I need to put out a HOWTO) ...

CD-R and DVD-R are single-groove, like a vinyl record and -ROM media.
The laser runs down a single, linear track, beginning to end -- a
revolution actually move the head outwards.

CD-RW, DVD-RAM, DVD-RW and DVD+RW are a MO discs, with sectors,
cylinders, etc...  When it does a single revolution, it comes back to
the same place it started, so it must "step up" to the next cylinder to
emulate the same.  That's why CD-RW, DVD-RAM, DVD-RW and DVD+RW are not
as "compatible" with players, which expect a "single groove."

The difference with MO it's also why you should use character-by-
character "record" for the "single-groove" media and a "rewrite"
approach, and not MO (either the kernel packet driver -- e.g., DVD-RAM
-- or dvd+rwtools -- e.g., DVD+RW/+R) for the block MO media.

MO also has a horrendous error rate, about 10^9 (1 per 1GB!).  The only
standard MO format (there are plenty of non-standard ones) that tries to
improve that is DVD-RAM.  It uses a verify after write and a media that
can be re-written 100,000 times, instead of only about 1,000.  But DVD-
RAM is not very player compatible at all -- only a few Panasonic and
Toshiba devices.

So for both longevity as well as consumer player compatibility, avoid
anything MO-based.

Long story short on DVD+R, Sony/Philips originally couldn't get DVD-R to
work on its drives, because of the design of its firmware and laser.
They promised a new record format in DVD+R.  Unfortunately, they even
ran into issues, and didn't get it out until the 3rd generation of DVD
+RW (2nd generation in the US -- the original 3GB DVD-R+W was Japan-
only), which also led to a lawsuit against HP and others (as their
DVD100i drives were marketed to support DVD+R).

I'm sure Sony/Philips wish they could turn back the clock as their
promised endeavors to beat Matsushita/Panasonic to market have pretty
much been the opposite (sands dual-layer, something Sony/Philips did
beat them to), but what is done is done.

In the end, DVD+R is really an pie-slice MO bastard, and not a single-
groove like DVD-R.  Adding the lack of a DAO mode, at least in older
drives, and DVD-R is the more compatible format.  Unfortunately the
Sony/Philips firmware was never designed for DVD-R and DAO, so you'll
typically have issues with record programs for it -- which requires you
to use dvd+rwtools.  I highly recommend you _avoid_ DVD+R (I know people
are going to differ with me on this).

Now Sony _was_ the first company to introduce a dual-format drive.  And
they seem to have improved the firmware as of late 2003-2004 (just about
the same time as Sony/Philips finally got DVD+RW/+R interoperability
improved between licensees as well as their own consumer players!), and
Jorg's cdrecord-ProDVD can drive many Sony/Philips drives now.  But DVD
+RW was really designed for data usage, not consumer players, hence why
it took awhile (despite what Sony/Philips ads say about the "most
compatible consumer format").

There's been a lot of shots fired on the DVD Consortium v. DVD+RW
Consortium front.  I try to avoid it.  I've been using DVD-RAM since
'98, and adopted DVD-R in 2000 on-ward.  Sony/Philips promised a lot,
but they let a lot of consumers down on anything except the fact that
DVD+RW is the fastest.  Of course, I could get into the whole CAV v. CLV
issue, which isn't really much of an issue on a "single groove" CD-
R/DVD-R (because the timing and pits are always the same, linear
relativity), but wreaks havoc with compatibility in a MO format (because
it's in a pie-slice like arrangement, which will vary in spacing,
etc...).

[ E.g., I retroactively call CAV CD-RW formats as CD+RW, because they
are very, very different and can even cause "damage" to drives than CLV
CD-RW.  Same deal, DVD-RAM and DVD-RW are CLV, DVD+RW are CAV.  There
are physical format differences between a CLV MO and a CAV MO. ]



On Sat, 2005-06-04 at 02:08 -0700, Mark Jarvis wrote:
> I have an NEC DVD-RW ND2500A (that's not the label I bought it under, 
> but that's what it really is.) It's supposed to read/write CDs, DVDs, 
>   DVD+Rs, and DVD-Rs. I'm basically dual booting between XP and CentOS 4.
> Following the recipe in "The Linux Cookbook", I tried to copy a DVD using:
>     dd if=/dev/hdd of=/tmp/diskfile.iso
> 	then
>     cdrecord dev=/dev/hdd fs=32m -sao -v -eject -dummy /tmp/diskfile.iso
> 	to test and
>     cdrecord dev=/dev/hdd fs=32m -sao -v -eject /tmp/diskfile.iso
> 	to actually record.
> I had a lot of trouble getting a good read of the whole original DVD--it 
> kept getting an I/O error at 94-95% of the way through. After multiple 
> cleanings and 20-40 attempts, I finally got the whole thing copied with 
> no reported errors. It then took me a couple of tries to get the 
> cdrecord options right and to run as root to get the requisite priority. 
> The "-dummy" run ran with no errors that I noticed--there was an LOT of 
> output--and "-dummy" didn't work. It wrote to the blank DVD anyway. I 
> then did a run without the "-dummy". Although the original will play on 
> both my PC and the DVD player hooked to the TV, the two copied DVDs 
> (DVD+Rs) are coasters. DURN!
> Any solutions, suggestions, pointers to articles I should read, etc. 
> will be appreciated.
> BTW, I've never quite gotten around to playing DVDs or my music files 
> (mp3 and Real Player .rmj files) from Linux. I'd appreciate being 
> pointed in the direction to start.



-- 
Bryan J. Smith                                     b.j.smith at ieee.org 
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