hard drive reliability for archival purposes

[Stephen Jones]

I work in a library where a lot of material has been stored to cds. The
director wants to find a medium with greater longevity and I have suggested
using hard drives; materials could be saved on duplicate hard drives and the
hard drives stored. In this regard:

1. He would like to see third party assessments of hard drive reliability
in general.

2. He would also like information on whether the platters themselves
deteriorate physically over time.

Any help will be greatly appreciated.

Stephen Jones

 

[Pinko_Commie]

I work in a library where a lot of material has been stored to cds. The
director wants to find a medium with greater longevity and I have suggested
using hard drives; materials could be saved on duplicate hard drives and the
hard drives stored. In this regard:

1. He would like to see third party assessments of hard drive reliability
in general.

2. He would also like information on whether the platters themselves
deteriorate physically over time.

Any help will be greatly appreciated.

If you want long term storage i suggest you look into SDLT's or similar.
Quantum claim that their SDLT media has a 30 year archival life.

I don't doubt that hard drives would work, but i couldn't vouch for the
archival life of them, there is alot more to go wrong with them.

 

[J.Clarke]

I work in a library where a lot of material has been stored to cds.
The director wants to find a medium with greater longevity

Why doesn't he look for the Holy Grail while he's about it. You aren't
going to find field-recordable media much more stable than good-grade
CDs. Magneto-optical may nose them out very slightly but no pure
magnetic media will be as stable.

and I have
suggested using hard drives; materials could be saved on duplicate
hard drives and the hard drives stored. In this regard:

1. He would like to see third party assessments of hard drive
reliability in general.

2. He would also like information on whether the platters themselves
deteriorate physically over time.

They don't deteriorate chemically or mechanically but over time if it's
not rewritten periodically the magnetic field loses intensity,
eventually becoming too weak for the heads to read. This is a fairly
slow process with modern drives, but they can't be trusted to hold the
data for the hundred years or so that a CD will hold.

Any help will be greatly appreciated.

Is there a specific problem you are trying to address?

 

[Arno Wagner]

I work in a library where a lot of material has been stored to cds. The
director wants to find a medium with greater longevity and I have suggested
using hard drives; materials could be saved on duplicate hard drives and the
hard drives stored. In this regard:

1. He would like to see third party assessments of hard drive reliability
in general.

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.

2. He would also like information on whether the platters themselves
deteriorate physically over time.

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

Any help will be greatly appreciated

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

 

[Simon]

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.

Bullshit on that shelf life claim.

They dont. But the bearings and the electronics do

Bullshit the electronics does when not being used.

and you might not have a computer left they work in.

MUCH more likely to be a problem with MOD.

Look at MOD. 3.5" MOD for this. That is presently the
only storage solution designed for long-term storage.

More bullshit.

Nothing else is suitable for long-term storage at the moment.

You dont even know that that is as far as drives
able to read the media in the future are concerned.

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.

You have absolutely no way of knowing if that is true or not yet.

In spades with the drives required to read the media.

What is more important is that the drive
manufacturers commit to their drives at
least reading the previous media generation.

For now. It remains to be seen how long that will be
true for as CDR and DVD take over most of their market.

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.

So your claim about 30+ years is obviously a lie.

Yet still all current 3.5" MO drives read and write them.

For now. It remains to be seen how long that will be
true for as CDR and DVD take over most of their market.

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.

Or maybe its just another example
of the odder ways the Japs do things.

Fujitsu have abandoned the 3.5" IDE hard drive market,
presumably because they werent making much money out of it.

Just as likely to happen with MOD too.

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.

 

[Mark Seeley]

You have absolutely no way of knowing if that is true or not yet.

You can never actually test this without waiting, but the shelf life will be
determined by performing Accelerated Life Testing on the media. It's not
going to be very accurate, but should provide a rough minimum on how long
it'll last. However, even then, these values are usually for archival
conditons. You'd need ideally fairly steady temperatures, not too hot/cold,
dark, etc. Fir example, CDs and DVDs will degrade very quickly in sunlight.
Also the cases you put them in often react over time with the material of
the CD/DVD. It'd need to be placed carefully in an acid free mount for
better results. Also with CDs, certain ones are better than others - for
example, Kodak released Kodak Gold CDs, and they were archival rated at a
long time more than the competitors - Gold is unreactive, and they worked on
making the plastic as long lasting as possible. A bad scratch, however, can
be fatal to it. Similarly, dropping a HDD will no doubt kill it, and
leaving it for a long time (as mentioned on a previous post) can cause the
motor or bearings to cease. Anything with moving parts is likely to be a
poor choice for long term storage.

Best bed, I'd say, is to find a couple of DIFFERENT types of archival media
and use BOTH. Make sure all data is duplicated on both. Maybe every 5
years, make sure all the data is transferred to another two types of media -
this should be enough to make sure you don't have compatibility problems.
In the UK there was a huge national project called the Domesday Project -
all the data was recorded on two virtually indestructable Videodiscs. The
problem was that the machines all died before they used the data, and they
had big problems recovering the data.

http://www.ananova.com/news/story/sm_719356.html

So in short, i'd stick with more than one set of media, and transfer them to
new media every few years - thus not giving the media time to degrade to the
point where data is lost. (note: Also store the two sets of data in
different locations - fire will destroy pretty much anything).

Mark

 

[Arno Wagner]

You can never actually test this without waiting, but the shelf life will be
determined by performing Accelerated Life Testing on the media. It's not
going to be very accurate, but should provide a rough minimum on how long
it'll last. However, even then, these values are usually for archival
conditons. You'd need ideally fairly steady temperatures, not too hot/cold,
dark, etc. Fir example, CDs and DVDs will degrade very quickly in sunlight.
Also the cases you put them in often react over time with the material of
the CD/DVD. It'd need to be placed carefully in an acid free mount for
better results. Also with CDs, certain ones are better than others - for
example, Kodak released Kodak Gold CDs, and they were archival rated at a
long time more than the competitors - Gold is unreactive, and they worked on
making the plastic as long lasting as possible. A bad scratch, however, can
be fatal to it. Similarly, dropping a HDD will no doubt kill it, and
leaving it for a long time (as mentioned on a previous post) can cause the
motor or bearings to cease. Anything with moving parts is likely to be a
poor choice for long term storage.

That is what I am talking about. Actually the Philips people think
that MOD will keep > 80 years under not so demanding conditions (MODs have
a closed cartridge), but with that lifetime the acelerated ageing
model gets shaky, so they say 30+ years.

[...]

Arno

 

[Rod Speed]

You can never actually test this without waiting,
Precisely.

but the shelf life will be determined by performing
Accelerated Life Testing on the media.

Which proves very little about the actual life that will actually be seen.

It's not going to be very accurate, but should
provide a rough minimum on how long it'll last.

Very rough. Not good enough to be able to support
his claim. There is no way of knowing if the media
will actually meet and exceed the claim yet.

However, even then, these values are usually
for archival conditons. You'd need ideally fairly
steady temperatures, not too hot/cold, dark, etc.

You'd actually need some evidence that with some of the media
alternatives that that really matters that much on the stability.

Fir example, CDs and DVDs will degrade very quickly in sunlight.

Sure, but thats trivially fixable.

Also the cases you put them in often react
over time with the material of the CD/DVD.

Not when there is no contact.

It'd need to be placed carefully in an acid free mount for better results.

Utterly mangled. That acid free is only relevant for paper.

Also with CDs, certain ones are better than others - for example,
Kodak released Kodak Gold CDs, and they were archival rated
at a long time more than the competitors - Gold is unreactive,

Pity about the rest of the CD that cant be gold.

and they worked on making the plastic as long lasting as possible.

And it remains to be seen if they succeeded there.

A bad scratch, however, can be fatal to it.

Sure, but thats trivially fixable too by just having multiple
copys, some of which are never actually used, just archives.

Similarly, dropping a HDD will no doubt kill it,

Sometimes it does, sometimes it doesnt. And its trivial to
mount the drive so it will survive being dropped anyway.

and leaving it for a long time (as mentioned on a previous
post) can cause the motor or bearings to cease.

seize, actually |-)

Anything with moving parts is likely to
be a poor choice for long term storage.

Its much more complicated than that.

Best bed, I'd say, is to find a couple of DIFFERENT
types of archival media and use BOTH.

It looked like thats what he was saying, tho he didnt say it very clearly.

Make sure all data is duplicated on both.

And reduce the risk with CDs by writing multiple
copys to different manufacturer's blanks as well.
They're so cheap that it makes no sense not to now.

Maybe every 5 years, make sure all the data is transferred
to another two types of media - this should be enough to
make sure you don't have compatibility problems.

And should help with media formats becoming
obsolete so that even if the media does last,
there's still drives around that can read it.

In the UK there was a huge national project called the Domesday
Project - all the data was recorded on two virtually indestructable
Videodiscs. The problem was that the machines all died before
they used the data, and they had big problems recovering the data.

http://www.ananova.com/news/story/sm_719356.html

And thats much more likely to be a problem with obscure
niche market products like MOD, and not with CDs which
should have drives that can read them for a long time yet.

So in short, i'd stick with more than one set of media,

Yeah, me too. And more than one copy of the CDs too.

and transfer them to new media every few
years - thus not giving the media time to
degrade to the point where data is lost.

That 5 years is likely a bit too cautious with CDs particularly.

(note: Also store the two sets of data in different
locations - fire will destroy pretty much anything).

Presumably an operation like that would understand that already.

 

[Arno Wagner]

On Wed, 5 Nov 2003 11:46:36 -0500

Why doesn't he look for the Holy Grail while he's about it. You aren't
going to find field-recordable media much more stable than good-grade
CDs. Magneto-optical may nose them out very slightly but no pure
magnetic media will be as stable.

MOD is not a magnetic medium. It is heated optically to around 300C and
then written magnetically. Reading is purely optical without the heating.
There is no magnetic field involved in the data storage itself. This
is done by pahe-change triggered by an external magnetic field.

From my experience I have numerous CD-Rs that failed after days,
weeks, months or years. I have been using MODs for 6 years now
and still have not lost a single byte.

Still CD-R is a cheap mass-market product wit carying tolerances
and no clear long-term stability.

They don't deteriorate chemically or mechanically but over time if it's
not rewritten periodically the magnetic field loses intensity,
eventually becoming too weak for the heads to read. This is a fairly
slow process with modern drives, but they can't be trusted to hold the
data for the hundred years or so that a CD will hold.

It is true that they loose magnetic field strength. Hovewer the
drive cannot rewrite the (also magnetic) servo information.
If a HDD has demagneticised enough it is dead. No rewriting
will help. For floppy disks your argument was true, but they
did not have servo information on the disks.

Arno

 

[Mark Seeley]

The media are rated for 30+ years. Contrary to

Which proves very little about the actual life that will actually be seen.


Very rough. Not good enough to be able to support
his claim. There is no way of knowing if the media
will actually meet and exceed the claim yet.


You'd actually need some evidence that with some of the media
alternatives that that really matters that much on the stability.


Sure, but thats trivially fixable.


Not when there is no contact.
results.

Utterly mangled. That acid free is only relevant for paper.


Pity about the rest of the CD that cant be gold.


And it remains to be seen if they succeeded there.


Sure, but thats trivially fixable too by just having multiple
copys, some of which are never actually used, just archives.


Sometimes it does, sometimes it doesnt. And its trivial to
mount the drive so it will survive being dropped anyway.


seize, actually |-)


Its much more complicated than that.


It looked like thats what he was saying, tho he didnt say it very clearly.


And reduce the risk with CDs by writing multiple
copys to different manufacturer's blanks as well.
They're so cheap that it makes no sense not to now.


And should help with media formats becoming
obsolete so that even if the media does last,
there's still drives around that can read it.



And thats much more likely to be a problem with obscure
niche market products like MOD, and not with CDs which
should have drives that can read them for a long time yet.


Yeah, me too. And more than one copy of the CDs too.


That 5 years is likely a bit too cautious with CDs particularly.


Presumably an operation like that would understand that already.

So it looks like generally we're in agreement, which is a good sign.
Regarding the acid free, I had been led to believe that the acidity in some
of the cases could react so as to damage the CD - apologies if I'm wrong on
that.

seize - umm, that's the one!!! (or cease to work correctly!!!! Maybe
that's what I was thinking in my mind... or is that just digging? Worth a
try!!)

Another couple of points to note - it is true that handling the CD/DVD can
cause it damage over time. In fact, when they degrade, this tends to occur
at the outer edge of the disc first. Many recommend when writing backups to
not fill the disc fully, so as to leave an unused ring at the outer edge (it
writes from the centre outwards) - again info on this is limited, but many
have had better results by doing this.

Also, be very careful how the CDs are labelled... sticky labels are a no-no
(you don't know what the glue is and what damage it'll do, and they
unbalance the CDs...) ALSO be careful with permanent pens - they are solvent
based, and the solvents can in time soak into the disc and affect it.

Probably things you knew, but still worth mentioning. And Rod, indeed I
would agree that given the cost of media now, using different manufacturers
for many copies is advisable. For others to note, this doesn't mean
different makes (many are made in the same factory - eg Traxdata is now
owned by Ritek - buy either, and you get disks from the same factory. Kodak
(usually) makes their own.

Presumably an operation like that would understand that already.

Hehe - that's what I keep telling myself! Company says they've had their
machine stolen...
Question: Do you have a backup?
Answer: Yes.
Question: What media is it on?
Answer: DVD.
Question: Where's the DVD?
Answer: In the machine that was stolen.
Statement: Muppet!

But yes, I would expect most here know about that )

Mark

 

[Rod Speed]

So it looks like generally we're in agreement, which is a good sign.

You one of those wimps, boy ? |-)

Regarding the acid free, I had been led to believe
that the acidity in some of the cases could react so
as to damage the CD - apologies if I'm wrong on that.

I'm not aware of any acid question with plastics.

Maybe you meant acid in the paper sleeve or something.

I wouldnt use paper sleeves of any kind with
archived CDs, I'd use jewel cases instead.

seize - umm, that's the one!!! (or cease to work correctly!!!!
Maybe that's what I was thinking in my mind...

Yeah, oddly appropriate in some ways |-)

or is that just digging? Worth a try!!)

Another couple of points to note - it is true that handling the
CD/DVD can cause it damage over time. In fact, when they
degrade, this tends to occur at the outer edge of the disc first.

I find that hard to believe.

Many recommend when writing backups to not fill the disc
fully, so as to leave an unused ring at the outer edge (it
writes from the centre outwards) - again info on this is
limited, but many have had better results by doing this.

I'd want some proper rigorous stats on that before I'd believe it.

Also, be very careful how the CDs are labelled... sticky
labels are a no-no (you don't know what the glue is and
what damage it'll do, and they unbalance the CDs...)

Yeah, never use them at all myself. Asking for trouble.

ALSO be careful with permanent pens - they are solvent based,
and the solvents can in time soak into the disc and affect it.

Easily avoided.

Probably things you knew, but still worth mentioning. And
Rod, indeed I would agree that given the cost of media now,
using different manufacturers for many copies is advisable.
For others to note, this doesn't mean different makes (many
are made in the same factory - eg Traxdata is now owned
by Ritek - buy either, and you get disks from the same factory.
Agreed.

Kodak (usually) makes their own.

Not sure they do anymore. Havent used them myself
for a long time now after they got out of the golds.

Hehe - that's what I keep telling myself!
Company says they've had their machine stolen...
Question: Do you have a backup?
Answer: Yes.
Question: What media is it on?
Answer: DVD.
Question: Where's the DVD?
Answer: In the machine that was stolen.
Statement: Muppet!

But yes, I would expect most here know about that )

His operation appears to be rather more than just another business tho.

 

[Fabien LE LEZ]

Another couple of points to note - it is true that handling the CD/DVD can
cause it damage over time. In fact, when they degrade, this tends to occur
at the outer edge of the disc first. Many recommend when writing backups to
not fill the disc fully, so as to leave an unused ring at the outer edge (it
writes from the centre outwards)

A better way if you accept not to put 700 MB of data may be to fill
the remaining space with PAR2 files. If you want to write 600 MB of
data on a 700 MB media (whatever the media is), add 100 MB worth of
PAR2 files, and you'll be able to recover all the data even if any 100
MB of the media is unreadable. Cf <http://parchive.sourceforge.net/>.

 

[Fabien LE LEZ]

Question: Do you have a backup?
Answer: Yes.
Question: What media is it on?
Answer: DVD.
Question: Where's the DVD?
Answer: In the machine that was stolen.

Wow... I've heard of people that store all their backups in the same
room as the machines, but this one beats them all ;-)

 

[Fabien LE LEZ]

I find that hard to believe.

Well, when I have trouble reading an oldish CD-R, the last MBs are
usually the unreadable ones. But I don't know whether it's because of
uneven degradation, or just because older writers didn't burn the last
MBs properly.

 

[Rod Speed]

Well, when I have trouble reading an oldish CD-R, the last MBs are
usually the unreadable ones. But I don't know whether it's because of
uneven degradation, or just because older writers didn't burn the last
MBs properly.

Havent see anything like that myself.

But then I dont normally get unreadable CDs, even with the first ones I burnt.

And thats going back quite a few years now.

 

[ted msn]

If you want long term storage i suggest you look into SDLT's or similar.
Quantum claim that their SDLT media has a 30 year archival life.

I don't doubt that hard drives would work, but i couldn't vouch for the
archival life of them, there is alot more to go wrong with them.

Just an off the wall thought and depends on the type and volume of data and
how much you wish to spend. Two media types have a proven long term
lifetime.
..

..

..

..

..

..

..

Paper and film !

Both are human readable. The read method has not changed in a long time now
(the mark 1 eyeball). Both can be machine readable to a geater or lesser
extent depends upon the data type.

But I would go along with the general view that more than one type of media
is chosen to avoid the common mode failure, so do not forget that CDs, DVD,
MOD, HHD are ALL "electronic" and will be subject to great change over the
next 10, 20, 50, 100.... years.

I have several books published in the late 1800s and I can still get info
from them. I have heard that there are even older books that can still be
read by the mark 1 eye ball .



regards

ted

 

[Pinko_Commie]

Paper and film !

heh heh, nice, a cyber-luddite ;-)

Both are human readable. The read method has not changed in a long time now
(the mark 1 eyeball). Both can be machine readable to a geater or lesser
extent depends upon the data type.

But I would go along with the general view that more than one type of media
is chosen to avoid the common mode failure, so do not forget that CDs, DVD,
MOD, HHD are ALL "electronic" and will be subject to great change over the
next 10, 20, 50, 100.... years.

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

 

[Al Dykes]

If you want long term storage i suggest you look into SDLT's or similar.
Quantum claim that their SDLT media has a 30 year archival life.

I don't doubt that hard drives would work, but i couldn't vouch for the
archival life of them, there is alot more to go wrong with them.

Magneto Optical (MO) disks are the gold standard for archival storage.
Fujitsu is a big player in this field, you can start reading here;

http://www.fujitsu.ca/products/storage/modisk/

You can contact the manufaturer of the media for information about
lifetimes under optimal storage conditions, etc. ISTR that PC
Magazine had an article about this technology a couple of months ago.
This stuff has been around for at least 15 years.

MO is in such massive use that it's a safe to say that you will have
years of advance notice before it's phased out.

IMHO the media is the easy part. You also need to keep the version of
the application that matches the data runnable, years from now. You
also need multiple copies of everything in multiple locations.

 

[J.Clarke]

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.

FWIW, I don't see Pinko Commie's post on my server, so I'll comment
here. Prerecorded CDs and DVDs store data in a physical manner with
pits on the disk--they'll last as long as the plastic of which they're
made holds up if they don't get scratched deep enough to cut into the
data area. But recordables of either the R or the RW variety store the
data chemically in a layer that changes its color or transparency when
exposed to certain frequencies of light at certain intensities. Rs
change phase permanently, RWs can be switched back and forth between two
phases. So -R and -RW only hold their data as long as that chemical
layer remains stable. There are a variety of chemistries uses, some
last longer than others.

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.

As to buying a CD-ROM drive in 100 years, you might be surprised--there
are a _lot_ of CDs out there and other than making them smaller there's
not a whole lot to be gained by newer technology, so CDs will likely be
around in the market for a long time, and drives that can play them even
longer. Bear in mind that you can still buy turntables that can play
records produced in 1900 and Best Buy has them on the shelf that can
play records produced in 1926.

 

[Neil Maxwell]

Another couple of points to note - it is true that handling the CD/DVD can
cause it damage over time. In fact, when they degrade, this tends to occur
at the outer edge of the disc first. Many recommend when writing backups to
not fill the disc fully, so as to leave an unused ring at the outer edge (it
writes from the centre outwards) - again info on this is limited, but many
have had better results by doing this.

I've done a lot of data gathering on failing CDRs in the last few
months, and the marginal ones are always worse at the edge than near
the center. Data transfer rates drop dramatically as you get near the
edges, and then fail completely. I've only got a few dozen data
points so far, but I'm convinced. All these CDs worked fine when they
were first burned.

Also, be very careful how the CDs are labelled... sticky labels are a no-no
(you don't know what the glue is and what damage it'll do, and they
unbalance the CDs...) ALSO be careful with permanent pens - they are solvent
based, and the solvents can in time soak into the disc and affect it.

There was a brand of labels recalled back in the early days of CDRs
(2x writers period) because of this problem. Don't remember the name,
but it'll be in the archives. I haven't seen any difference in my
tests between failure rates of labeled vs. unlabeled disks, but all my
labels were one particular brand, so that doesn't extrapolate to other
brands and other glue formulas.

As for marker solvent, I'd have to believe that 95% of the solvent
would have evaporated shortly after writing, and the other 5% would
have diffused out over the next 24 hours or so, mostly away from the
disk, leaving trace amounts in the ink. Just a guess on the numbers
and rates, but I have a good bit of practical experience on solvent
and oil diffusion.

Someone mentioned Kodak gold; I've got some Kodak gold and silver
disks that are failing and were burned over the last 3-5 years. The
only disks I haven't seen dramatic failures on are TY, and I only
started using them 2-3 years ago. I'm not planning on them lasting
another 3 years without problems, but I'll be pleasantly surprised if
they do.


Neil Maxwell - I don't speak for my employer