Re: Somewhat OT: Data backup using Blu Ray

On Sat, 29 Nov 2008 18:32:13 -0800 (PST), mpm <mpmillard@xxxxxxx> wrote:


Possibly, but a couple years ago Sony demo'd a new type of optical
drive (like a CD, only the media is encased), which cuts the disc with
multiple lasers. The capacity was enormous. Like 21TB. At the
time, they promised a R/W version, but I don't know if it's
commercially available. It will take time for this to enter the
consumer arena. Then conventional magnetic-technology hardrives go
the way of the dinosaur.

Yeah, and nearly ten years ago it was the optical cube. A one inch
square device that could store several Terabytes of data by using two
lasers. Entire 1GB pages could be written and read in milliseconds. It
never came to pass, but they did manage to write ten GB to a roll of
clear shipping tape once (a cross section of it).

That one never happened either, and it had no moving parts (other than
MEMS), which means it should have been even easier, and result in a more
reliable device. It did not happen..

The disc based device may well happen, but it will be years off, and
data integrity will have to be spot on or the hard drive will linger for
another two decades.
The fact that the read surface of an optical disc can be scratched.
leading to data loss, is a disqualifying factor right there alone.

There is a reason that hard drives have come as far as they have. That
reason is data integrity. Despite what the dopey *** BobW says, they
are second to NONE! Been that way for decades, and it will be that way
for a long time to come. It isn't about data capacity, it is about
reliable storage integrity, and these FULLY ENCLOSED devices will always
have an upper hand in that area.

Even though optical is non contact, burned media is not actually
"burned". It is a plastic layer which merely gets impinged upon by the
laser. No actual "pit" is actually made. This plastic layer can lose
that definition, even on write once disc media.

As far as Sony's new technology goes, we have always known that
holographic storage technology is what it would take to get higher
capacity on optical, but the same drawbacks still linger. Those
drawbacks are deal breakers in oh so many scenarios. The main one being
true write on the fly capacity. Most discs need to be authored in
"sessions" which means a complete datagram gets written. They are not
friendly with single file write scenarios... at all...
.

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