[SLUG] Re: pseudo block device piping to smb or nfs -- MO = { CD-RW, DVD-RW, DVD+RW, etc... }

From: Bryan J. Smith (b.j.smith@ieee.org)
Date: Fri Sep 10 2004 - 12:14:58 EDT


On Fri, 2004-09-10 at 10:25, Mario Lombardo wrote:
> When you refer to "MO," are you referring to Magneto-Optical?

Is that not what I called it in a previous post?
(I post some much verbage, I don't blame you for missing it)

> 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.

If you use CD-RW, DVD-RW or DVD+RW, you _are_ using MO.

It's "raw" MO. Error rates are rediculously high -- 1 per billion
(10^9) -- that's 1 every 1GB! Magnetic and WORM are only 1 per 10
trillion (10^13, 1 per 10TB).

DVD+R is also a bastardized MO, not WORM like DVD-R, because
Sony/Philips couldn't get WORM to work for DVD-R in their first 3
generations of drives. Heck, they couldn't even get DVD+R to work in
the first 2 generations. Lawsuits are currently pending over this.

> 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.

That's "modified" MO. Before Panasonic PD-CD/DVD-RAM, they were _all_
proprietary.

Panasonic suggested DVD-RAM as the official DVD consortium MO format for
optical archiving and "early adopters" that were not consumers. It was
then up to Pioneer, Sony, Philips and others to come up with a less
reliable, more consumer-compatible format.

Sony/Philips split off because they thought they could build a better MO
with full CD-R/RW WORM support. All they ended up doing is creating a
drive that, until about 2 years ago, could not even do DVD-R. DVD+R is
not as compatible, despite the marketing BS.

Their 3G "replacement" for DVD-RAM didn't hit until after DVD-RAM
already moved to 4.7GB, and Pioneer came out with the first DVD-R(G)
drives. So they were limited to Japan.

> 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.

Yes, I know who they are. They were right off of University drive (not
even a half-mile from UCF). They also wrote drivers.

-- 
     Linux Enthusiasts call me anti-Linux.
   Windows Enthusisats call me anti-Microsoft.
 They both must be correct because I have over a
decade of experience with both in mission critical
environments, resulting in a bigotry dedicated to
 mitigating risk and focusing on technologies ...
           not products or vendors
--------------------------------------------------
Bryan J. Smith, E.I.         b.j.smith at ieee.org

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