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When you refer to "MO," are you referring to Magneto-Optical?
I've never had the privilege of using MO drives, but from what I've heard,
they're impervious to UV light or magnetic fields. You need both laser light
and magnetics to create a write to the disk. Supposedly this made it a
fault-tolerant backup solution with a very high archival quality, which is
why some shops used it as opposed to tape.
In fact, my old roommate used to work for a company in the Orlando area (now
defunct) that made large cabinet-sized MO drive arrays. The embedded system
for the SCSI/network-attached chassis ran Linux.
/mario
On Friday 10 September 2004 09:19, Bryan J. Smith wrote:
> 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).
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