Storage media lifetimes

This subject has been bounced around on here a number of times and the
consensus has been that we really don't know the practical life for
files stored on digital media.

The latest issue of "Computer World" (Jan 10, 2006) has a good article
on the life or storage media or rather the lack there of.
http://www.computerworld.com/blogs/n...om=story_picks
I don't know if you can get to it without being registered or not, but
the gist of the article is the storage life of "burned" optical media
is far, far shorter than has been expected or claimed.

Of course Hard drives make poor archival media as well. In the end
the best media for corporations was still considered to be magnetic
tape, but it takes special storage conditions and areas where it is
well protected to be considered long lived, but it is much longer than
most optical even if far more prone to failure from external sources.
Tape needs to be periodically re tensioned, stored on edge, and
protected from contaminants, magnetic fields, and heat. Their
requirements to get the maximum life out of tape pretty much puts it
beyond the scope of the individual or small business. OTOH, tape
still has the potential for the longest life of any archival media
other than the original film and paper documents.

Optical disks need to be stored on edge, in the dark, and kept away
from heat. They should not be written on, nor should they have paper
labels stuck on them. which makes it difficult to remember what's on
which one. When you have a 1000 or so this might get to be a problem.
When you think of the G-forces on a 50X disk I can't imagine putting a
paper label on one.

The upshot of the article, as has been said many times here, is no
media last forever. The surprise was the relatively short lifetimes
given for CDs (3 to 5 years) and even tape at 20 to 30 years "under
ideal treatment and conditions". This all leads to the requirement
for a periodic data migration and adds new meaning to the idea of
digitizing the "old family slides".

I've been testing some old CDs for quality and what I've found so far
shows those of 5 years old to be in good shape (with no detectable
degradation) and I've certainly not taken any special precautions
with them. Many are also the inexpensive ones that are listed as
having short lifetimes. The only failures, which were expected were
of the R/W CDs as they are notorious for not being reliable.

The problem with testing a lot of CDs this old is the time required as
they are slowwww.... compared to today's CDs and DVDs. Then take the
old 2X DVDs that are full. You turn the computer loose and go do
something else.

Now I need to go out to the shop and bring in a hundred or so CDs that
are the oldest on hand to see how well they have faired.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

On Tue, 10 Jan 2006 23:34:44 -0500, Roger wrote:

The latest issue of "Computer World" (Jan 10, 2006) has a good article
on the life or storage media or rather the lack there of.
http://www.computerworld.com/blogs/n...om=story_picks

Roger,

you think it's a good article, but it may be a bad article,
thriving on fear and lying.

I don't know if you can get to it without being registered or not, but

I could.

the gist of the article is the storage life of "burned" optical media
is far, far shorter than has been expected or claimed.

If the article says the truth, which it probably doesn't.

To give an example, the article says that writing on a CD or
sticking a label on it reduces the retention time. However, this
is untrue in most cases. The exception is only that you use a
sticker with a glue that dissolves the CD or DVD. How a pen
would do that is beyond my physical and chemical knowledge.

The article states such things, but doesn't even cite any
evidence.

Hans-Georg

--
No mail, please.

Roger,

you think it's a good article, but it may be a bad article,
thriving on fear and lying.


Perhaps, but I'm not so sure. I've had multiple CD-Rs go bad over the
years since I've had a burner and I don't place a lot of faith in
recordable DVDs either, my most recent catastrophe being when I burned
about a 1000 digital pictures to a DVD-R. When I went to read the disc
two weeks later, my computer (and 3 others I tried it in) claimed it
was unreadable and/or damaged. Fortunately, I still had all the photos
on my hard drive. Much is dependent on the brand of recordable CD or
DVD you buy as well. I've had entire spindles that aren't worth a
damn. I've also had two hard drives meltdown in the last 12 years.
This is perhaps the one thing that's kept me from moving all my old
film negatives over to a digital storage medium, I just don't know what
to trust yet. I guess the only way I'd be able to rest easy for the
time being is continue keeping 3 or 4 copies of my digital photos in
various places, i.e. friends houses, safety deposit box, buried in the
backyard. ;-)

writes:
Perhaps, but I'm not so sure. I've had multiple CD-Rs go bad over the
years since I've had a burner and I don't place a lot of faith in
recordable DVDs either, my most recent catastrophe being when I burned
about a 1000 digital pictures to a DVD-R. When I went to read the disc
two weeks later, my computer (and 3 others I tried it in) claimed it
was unreadable and/or damaged.

That sounds like a write failure, rather than the disk going bad
sometime after it was written. Was the DVD-R readable the minute
after you wrote it, but unreadable two weeks later?

On Wed, 11 Jan 2006 11:54:41 +0100, Hans-Georg Michna
wrote:

On Tue, 10 Jan 2006 23:34:44 -0500, Roger wrote:

The latest issue of "Computer World" (Jan 10, 2006) has a good article
on the life or storage media or rather the lack there of.
http://www.computerworld.com/blogs/n...om=story_picks

Roger,

you think it's a good article, but it may be a bad article,
thriving on fear and lying.


Which is why I said I was going back through my CDs and DVDs checking
quality.

I did find one with some failures, BUT it was a rewritable CD and
those are noted for not being reliable.

I have gone back to the oldest I could find (so far) which is 1998
with no failures or even bad blocks. (so far)

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com


I don't know if you can get to it without being registered or not, but

I could.

the gist of the article is the storage life of "burned" optical media
is far, far shorter than has been expected or claimed.

If the article says the truth, which it probably doesn't.

To give an example, the article says that writing on a CD or
sticking a label on it reduces the retention time. However, this
is untrue in most cases. The exception is only that you use a
sticker with a glue that dissolves the CD or DVD. How a pen
would do that is beyond my physical and chemical knowledge.

The article states such things, but doesn't even cite any
evidence.

Hans-Georg

As for CD-Rs going bad, I've had some go bad several months after
initially being readable, others (mostly CD-RWs, which I don't use
anymore) have been bad from the moment of burning. The DVD-R in
question was initially readable after burning. That's one of first
things I do anymore after burning to make sure the data made it to the
disc okay. Two weeks later I put it in my computer and the disc was
unreadable. This also happened to be the spindle where several of the
discs were giving me read problems after initially being readable, so I
****-canned the whole lot (TDK, bought at Costco).

On 11 Jan 2006 17:51:10 -0800, wrote:


Roger,

you think it's a good article, but it may be a bad article,
thriving on fear and lying.


Perhaps, but I'm not so sure. I've had multiple CD-Rs go bad over the
years since I've had a burner and I don't place a lot of faith in
recordable DVDs either, my most recent catastrophe being when I burned
about a 1000 digital pictures to a DVD-R. When I went to read the disc
two weeks later, my computer (and 3 others I tried it in) claimed it

Did you run a verification on the disk after burning it? This really
sounds like a burn error. Every time I burn one I run a verification
and I have virtually thousands of CDs and DVDs. Any disk with ANY
read errors is thrown out and redone.

was unreadable and/or damaged. Fortunately, I still had all the photos
on my hard drive. Much is dependent on the brand of recordable CD or
DVD you buy as well. I've had entire spindles that aren't worth a
damn. I've also had two hard drives meltdown in the last 12 years.

Having now scanned past 30,000 or so negatives (near as I can tell) I
have only had one spindle of CDs that had several bad. I did have
some old DVDs that one of my drives didn't like and wouldn't write to
them. They worked fine in the other drives. They are still readable
on all 4 current drives/machines

I've gone back as far as 1998 which is the oldest CDs I have (I think)
and running a block level file check have not found one bad one...yet.
Some of those have been around and have a lot of scratches on the
face. Wipe 'em off and they read "and test" fine.Other than keeping
most of them in jewel cases I've not gone to any particular effort to
protect them. Some end up in piles, for a week or two before being put
back on a spindle.

This is perhaps the one thing that's kept me from moving all my old
film negatives over to a digital storage medium, I just don't know what
to trust yet. I guess the only way I'd be able to rest easy for the
time being is continue keeping 3 or 4 copies of my digital photos in
various places, i.e. friends houses, safety deposit box, buried in the
backyard. ;-)

The biggest things about scanning the old family slides (and
negatives) is to be sure and keep the slides and negatives, develop a
good naming convention, and a scheduled data migration program with
periodic checks on data verification in addition to keeping multiple
copies. That is a lot of work.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

wrote:
Roger,

you think it's a good article, but it may be a bad article,
thriving on fear and lying.


Perhaps, but I'm not so sure. I've had multiple CD-Rs go bad over the
years since I've had a burner and I don't place a lot of faith in
recordable DVDs either, my most recent catastrophe being when I burned
about a 1000 digital pictures to a DVD-R. When I went to read the disc
two weeks later, my computer (and 3 others I tried it in) claimed it
was unreadable and/or damaged. Fortunately, I still had all the photos
on my hard drive. Much is dependent on the brand of recordable CD or
DVD you buy as well. I've had entire spindles that aren't worth a
damn. I've also had two hard drives meltdown in the last 12 years.
This is perhaps the one thing that's kept me from moving all my old
film negatives over to a digital storage medium, I just don't know what
to trust yet. I guess the only way I'd be able to rest easy for the
time being is continue keeping 3 or 4 copies of my digital photos in
various places, i.e. friends houses, safety deposit box, buried in the
backyard. ;-)


My experience with CD's has been such that I would prefer to write the
data to an old cassette tape recorder. Sigh.

On the other hand, I have some 20 year old floppies that can still be
read, and many that can't.... I am spreading my data across me hard
drives, and will copy it to each new one as I buy them. This has worked
pretty well, so far. For long term, I really don't care, since I am
unlikely to be around more than another 20 years.

On 11 Jan 2006 17:51:10 -0800, wrote:

Perhaps, but I'm not so sure. I've had multiple CD-Rs go bad over the
years since I've had a burner and I don't place a lot of faith in
recordable DVDs either, my most recent catastrophe being when I burned
about a 1000 digital pictures to a DVD-R. When I went to read the disc
two weeks later, my computer (and 3 others I tried it in) claimed it
was unreadable and/or damaged.

Who was the manufacturer of the media?

You have to use first class media, otherwise you will surely
have such failures.

First choice is Maxell, followed by Verbatim (after careful
testing).

Hans-Georg

--
No mail, please.

wrote in message
oups.com...
SNIP
The DVD-R in question was initially readable after burning.

That would only tell you that the data could be read, with an unknown
amount of error correction(!)

Although an immediate verification failure would be a significant
warning towards media incompatibility, if you want to get a bit more
assurance you'll need a better tool than simply rereading the file.

On recorders that report it, the amount of error detection and
correction can be obtained with a software tool. The relative amount,
and severity, of the errors detected will indicate the suitability of
the media for the specific recorder at a specific writing speed. It
will then over time indicate the deterioration rate, and provide a
warning for imminent (even if not show-stopping yet at the moment)
disasters.

For a simple test application you could use
http://www.cdspeed2000.com/go.php3?link=download.html
Variations in read speed are a first indication of trouble ahead, and
reports of C1/C2 errors give better/quantifiable clues.

"Plextor" recorders (don't know if that applies to all models) come
with a PlexTools Pro application that allows to do more in depth
testing. They also list compatibility of media with their drive models
at
http://www.plextor.be/technicalservices/technology/cdrmedia.asp?choice=Supported%20media
..

That will allow to have an initial, and ultimately a final warning,
tool before having to resort to data recovery tools such as e.g.
http://www.smart-projects.net/isobuster/ and
http://www.infinadyne.com/cddvd_diagnostic.html.

Bart