hard drive reliability for archival purposes

  • Thread starter Thread starter Stephen Jones
  • Start date Start date
CD's and DVD's aren't electronic as such, they store the data in a physical
manner (pits on disc) but try going down to PC World and buying a CD-ROM
drive in 100 years :-)
Click to expand...

The bottom line is, refresh your data every few years!
Anyway, if you had 100 CDs a few years ago, today you can transfer the
data to 15 DVDs, and in a little you'll be able to transfer them to
one or two discs.
Refreshing data can be a hassle, but in return you save space.
 
That's not entirely true. The CDs I referred to in an earlier post in
this thread were the Kodak Gold Ultima's... these contain an actual
gold reflective layer,
Click to expand...

Which is irrelevant. They can have gold, platinum, or gold-pressed
latinum and the data will still be held in the chemical layer.
unlike(as you say) some which look Gold and
are not. The Kodak Gold Ultima's I do not believe are made (since
2002?) but under test have shown excellent results for archival
storage. Similarly, the Kodak Ultima's contain a real Silver layer,
with added Gold - this acts to make the silver less reactive and thus
improves their lifetime.
Click to expand...

Doesn't matter what the reflective layer is made out of, it's the dye
layer that holds the data, and Kodak Gold Ultimas, like all "gold" CDs,
holds the data in a layer of phthalocyanine dye.

The little dinky laser in a CD burner does not have enough power to burn
pits in a gold mirror.
 
There's also a misconception that CDs that have a gold color store the
data in a layer of gold metal--they do not, they store it in a chemical
layer that has a yellow cast and so looks gold against the reflective
layer.
Click to expand...

That's not entirely true. The CDs I referred to in an earlier post in this
thread were the Kodak Gold Ultima's... these contain an actual gold
reflective layer, unlike (as you say) some which look Gold and are not. The
Kodak Gold Ultima's I do not believe are made (since 2002?) but under test
have shown excellent results for archival storage. Similarly, the Kodak
Ultima's contain a real Silver layer, with added Gold - this acts to make
the silver less reactive and thus improves their lifetime.

Mark
 
Arno said:
HDDs are very reliable per usage hour. They suck at reliability per
age hour. Not a good idea. You might loose a disk after some years
in storage completely, as they are only designed for a shelf-life
of 5 years.


They dont. But the bearings and the electronics do and you might not
have a computer left they work in.


Look at MOD. 3.5" MOD for this. That is presently the only storage
solution designed for long-term storage. Nothing else is suitable for
long-term storage at the moment. This still constantly surptises me,
but that is just how it is. The obnly other option for long
term storage is to copy the data every few years and to keep
several copies.

The media are rated for 30+ years. Contrary to CD-R they actually
reach and exceed that number. What is more important is that the
drive manufacturers commit to their drives at least reading the
previous media generation. Media come in 2.3GB, 1.3GB, 640/540MB,
230MB and 128MB sizes (the smaller the older). You cannot get 128MB
media today. they must be something like 15 years old by now. Yet
still all current 3.5" MO drives read and write them.

In many places in Europe they are used to store digital X-rays (have
to be kept available for 20 years). They are also widely used in Japan,
I am told. Maybe the Japanese just take a longer term view on data
storage.

Another benefit is that the media are relativevely cheap (not
compared to low-end unreliable consumer grade trash like cd-r,
of course), while drives are more expensive.

You can get MOD libraries, where a feeder mechanism feeds few
drives from a large MO disk storage.

Some more info here:

http://www.fcpa.fujitsu.com/products/mo-drives/

For the larger 5.25" drives:

http://www.storagebysony.com/OEM/categories/categorymain.asp?id=5#

Some price quotes, including MOD jukeboxes:

http://www.mysimon.com/4007-3213_8-0.html

I am sure that Fujitsu, HP, Sony, Compaq (I think),...

will give you more detailed Information, when you explain
your needs to them.

Arno
Click to expand...


Hello, Arno:

Recall, however, that DVD-RAM rivals MOD in reliability. In addition to
being offered in significantly higher capacities (up to 9.4GB,
double-sided cartridge) than the former medium, it enjoys certain other
advantages, mentioned on this Pioneer Web page:

DVD Technical Guide -Chapter 7 DVD-RAM- [7.1 Background of the DVD-RAM
Specification/7.2 2.6 GB DVD-RAM Specifications]
<http://www.pioneer.co.jp/crdl/tech/dvd/7-e.html>

DVD-RAM may be seen as a "successor" (of sorts) to MOD; Panasonic
(DVD-RAM's "champion"), at least, seems to feel that way. ;-)


Cordially,
John Turco <[email protected]>
 
Doesn't matter what the reflective layer is made out of, it's the dye
layer that holds the data, and Kodak Gold Ultimas, like all "gold" CDs,
holds the data in a layer of phthalocyanine dye.
Click to expand...

Apologies - didn't realise that.

Mark
 
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