Can you forward me that e-mail? I don't think it went to the list. I'm also interested in DVD formats.
peace, core
-----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.0 (GNU/Linux)
iD8DBQFCP+ZbGAuLrxOyeJMRAtI7AKDmO/Rcm/DX9lShmYkM81hFP3cE3ACfSSSC VLTj4pzKaVy51f8FJplpsMk= =Ki+Y -----END PGP SIGNATURE-----
_______________________________________________
This list appears to have mailman configured as to NOT put the rlug's list address in a reply. Is there any specific reason for this? In the LVLUG we have set "Where are replies to list messages directed?" to go to "The List" so yuo don't have to add the list address in every reply.
Here is the post I sent which was from one of our members:
--------------------------------------------------------------------------
DVD+R and DVD-R are radically different mediums.
DVD+R is still an MO (magneto-optical) variant media introduced after Philips failed to get DVD+RW lasers to record DVD-R WORM (Write-Once, Read-Many).
Pressed ROM and WORM are single grove, MO is pie-slice (like a magnetic disc).
There is also an issue between Constant-Linear-Velocity (CLV) and Constant-Angular-Velocity (CAV) when it comes to pie-slice layout (long story).
If you don't know what you are doing, especially with CLV MO media in a CAV MO write, you can not only shorten the life of your recorder/re-writer, but readers as well (including several of my systems in the past).
These technical details are little known.
But if you stick with WORM media (which works the same for both CLV and CAV -- one long groove) like CD-R and DVD-R, you'll never have issues.
The whole DVD+RW drive history (beginning with the 3GB Japaneses-only release) through the 1st-Gen false advertising of DVD+R compatibility has been marred with lawsuits.
Sony/Philips has always introduced technical issues with their CAV MO media and drives (again, long story).
Pioneer has continually beaten them to market on availability and reliability, despite Sony/Philips' speed over-hype.
And Sony/Philips' advertisements that DVD+R/+RW is the "most compatible" format is blantant false advertising (based on shaky non-US sales of total drives and assumed same-vendor compatibility).
DVD-R (technically this is DVD-R(G) for General) is most consumer player compatible when recorded in "Disc-At-Once" (DAO) mode.
Unfortunately DAO is incompatible with Burn-Proof technologies, so most computer DVD-R/RW drives use "Session-At-Once" (SAO) or "Track-At-Once" (TAO).
SAO works for all data and most consumer uses being that it writes a single session, but still allows Burn-Proof.
Many newer drives can do both DVD-R/RW and DVD+R/+RW, although firmware still plays a big part.
Sony/Philips consortium drives are natively MO-only DVD+R/+RW, so even if they do DVD-R, they can't do DAO.
Pioneer drives tend to be a little slower, but do the full DVD-R spec, including DAO, as well as MO formats such as DVD-RW, DVD+RW and the DVD+R variant.
Ironically some of the cheapest drives ($60 -- e.g., LG GSA-416x series) are a hybrid Matsushita-Pioneer logic-laser also known as "SuperDrives" or "MultiDVD."
In addition to DVD-R/RW and DVD+R/+RW, they also do either Type 1/2 (more costly drives for loader mechanism) or just Type 2 (no cartridge, but $60 drives) DVD-RAM.
Despite countless and poorly written articles, DVD-RAM does not get its 100x longevity/reduced error-rate over standard MO from its Type 1 Cartridge option , but from its pre-formatted media, verify-after-read and other laser-media enhancements that are also in the Type 2 cartridgeless.
You can tell a DVD-RAM disc because it has its pre-formatted CLV "dashes" spiraled out over the media.
DVD-RAM was the first end-user DVD format introduced (1997 only $500 - I know, I had several in use) because it was an optical archiving standard still in widespread use.
Based on Masushita's existing PD-CD firmware, it worked in Linux on Day 1 (no special tricks - mount just like a regular disk - add UDF filesystem support if you wanted, or just use Ext2).
MO has a horrendous error-rate, 1 in 10**9 -- that's 1 byte every 2 CD-RW and 5 bytes on a *single* DVD-RW or DVD+RW.
And those errors are *not* reported until you attempt to read them later.
Rewrites of standard MO are also only 1,000 which quickly becomes an issue for standard FAT formats (hence why UDF filesystem is recommended).
DVD-RAM using pre-formatted media allows 100,000 rewrites and has a 30 year shelf-life (especially with the cartridge option that protects from the environment better).
It also uses verify-after-write to catch any errors as they are written, althoughthe performance hit is major.
For most consumers, DVD-R WORM sufficies. It has a much lower error rate than MO, and media longevity is 15+ years. Consumer device compatibility doesn't get any better, especially in DAO. At the same time, SAO works for data DVD-R just as well as CD-R.
If you have long-term archiving needs, especially if changes may need to be made, DVD-RAM is what you want.
But performance and compatibility outside data (and even in non-DVD consortium drives like Sony/Philips licensees) will be poor.
At $60, I like my 5th Gen DVD-RAM drives like the LG GSA-4162.
I can record CD-R and DVD-R with the stock cdrtools-2.0dvd.
I can rewrite DVD-RAM with the stock kernel, and DVD+RW with a patch.
I'm still rewriting to 7+ year-old DVD-RAM discs.
Can's say the same for CD+RW or 1st gen DVD+RW discs after a few years.
----------------------------------------------------------------------------
Doug P
_______________________________________________ RLUG mailing list [email protected] http://lists.rlug.org/mailman/listinfo/rlug
