On Fri, 2004-09-10 at 07:44, Paddy wrote:
> Bryan;
> Are any of DVD-RAM drives mature enough that you would want to purchase
> one at this time or would you rather wait until the software offers more
> features and the bugs are worked out.
Your joking, right? DVD-RAM is the most mature MO technology ever. It
solves a lot of issues, with an open standard. And it's laser
_reads_everything_.
Please understand the release of the DVD consortium standards:
1994: 3.96GB DVD-R(Authoring) WORM
1997: 2.6GB DVD-RAM (Professional Archiving) MO
1999: 4.7GB DVD-R(G[eneral]) WORM
2000: 4.7GB DVD-RW (Consumer Archiving) MO
Pioneer DVD-R(A) was first as it was a very compatible WORM (record)
technology for authoring, at a very high price point (originally entry
5-figures). That came down later, but it was an "early adopter" WORM --
like leading-edge professionals.
Panasonic DVD-RAM was next, based on their existing Phase-Dual CD
(PD-CD) technology. MO (CD-RW, DVD-RW, DVD+RW) has a _massive_ error
rate -- 1000x worse than magnetic or WORM -- about 1 in 10^9 (1 error
per GB). That means a CD-RW averages 1 error every 2 CDs, and 5 errors
every (later on) DVD-RW or DVD+RW. PD solves this by using various
approaches -- pre-sectored/pre-formatted MO (DVD-RAM looks like it has
clear chads ;-), verify-after-write, etc... (it's _more_ than just the
cartridge, which is _optional_). Therefore the shelf-life is about
30-years for DVD-RAM with 100,000 rewrites, versus about 3 years and
only 1,000 rewrite (which can be made where the allocation table is ;-)
for other MOs -- let alone the errors that occur on first write! The
downside is that DVD-RAM is _not_ consumer compatible -- it is a format
for professional archiving, but the drives started at only $500 back in
1998.
Because DVD-RAM uses the same firmware as PD-CD, and embedded Linux was
a heavily used optical archiving platform, PD-CD drivers for Linux were
developed. As such, DVD-RAM support (direct block device) in Linux
worked from Day 1.
Panasonic followed DVD-R(A) with DVD-R(G) about 5 years later, which was
the General format and availability of DVD-R. DVD-R(G) does not allow
certain sectors to be written where the symmetric keys for VOB encrypted
files are encrypted with the public CSS key for various players. Drives
were also 3 figures to start.
About the same time, Panasonic launched the 2nd Gen DVD-RAM with the
full 4.7GB/side capacity. Performance increased, but DVD-RAM is _slow_
by its very write-after-verify design (even the latest gen is only 3x --
which comes out to 1.6x actual).
In 2000, Pioneer launched its consumer DVD-RW drive, which introduced a
simple MO format. Like DVD+RW (which I won't get into here -- long
story), it has none of the reliability of DVD-RAM. But it is far more
consumer player compatible.
By 2001, Panasonic started shipping its 3rd Generation drive with 1x
DVD-R(G) and 4.7GB DVD-RAM. In 2002 they released one that did
DVD-R/RW/RAM, with firmware compatible with both DVD-RW and DVD-RAM.
The key to adding a DVD-RW laser meant it could now do CD-R/RW as well
(DVD-RAM lasers do not offer compatibility with writing CD-R/RW).
In 2003, the DVD-R+R/RW+RW/RAM "SuperDrives" were released. Last year I
purchased a $75 LG GSA-4081B 4/8/2/4/3x DVD-R+R/RW+RW/RAM drive and
earlier this year a $65 LG GSA-4082B 8/8/4/4/3x DVD-R+R/RW+RW/RAM. The
sucker works with _both_ Jorg's ProDVD as well as the CDRTools DVD patch
(in Fedora Core 1/2). The DVD-RAM packet write function has been in the
kernel since 1.3 -- stock since 2.0.
These are in addition to my existing 2.6GB 1Gen (SCSI) and DVD-R/RAM
3Gen (ATA) which only have Panasonic DVD-RAM firmware (no DVD-RW
compatibility/firmware).
-- Bryan
P.S. My main reason for adopting DVD-RAM back in 1998 was because it
was the "universal reader." Even my old 2.6GB/side drive, now over 6
years old, will read even DVD+R/RW. DVD-RAM is like having AB blood,
the "universal receiver." And now with the latest "SuperDrives," it is
also like having O blood too, the "universal donor."
The laser just reads everything too. I've had copy protected audio CDs
that my DVD-RAM drives will extract digital from (albeit at only 0.5x or
slower, but they do).
-- Bryan J. Smith b.j.smith@ieee.org ------------------------------------------------------------------ "Communities don't have rights. Only individuals in the community have rights. ... That idea of community rights is firmly rooted in the 'Communist Manifesto.'" -- Michael Badnarik----------------------------------------------------------------------- This list is provided as an unmoderated internet service by Networked Knowledge Systems (NKS). Views and opinions expressed in messages posted are those of the author and do not necessarily reflect the official policy or position of NKS or any of its employees.
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