CD Woes

[David Kaye]

Not exactly on-topic, but there are all kinds of sysadmins here, so I
thought I'd drop a line or two about CDs.

I backup stuff onto CDs all the time. My best programs, tools, data,
photos, and whatnot I back up every 6 to 12 months from the last good copy.
So, my good stuff can be 10th or 12th generation going back 10 or 12 years,
but it's all readable.

But then there's the other stuff, the backups I did once for customer
projects, etc. Whenever I had to handle customer data I always made 2 CD or
DVD backups of it in case during some operation I'd accidentally wipe a
disk. Only happened once, so I'm glad I had the backups.

So, I'm going through boxes of the one-time backups ready to scratch the
surface or break the CDs in two before trashing them. No need to make them
unreadable -- they're ALL unreadable! I was careful to put the CDs and DVDs
on the floor of my closet where they wouldn't be exposed to heat or light,
which damages the dye used in recordable CDs. Well, not even the special
"lasts a lifetime" gold-colored CDs survived. Mind you, these are CDs and
DVDs I recorded once just as temporary backups; the latest in this batch is
from 2007, so it's no great loss for me.

I guess this is a reminder for people who don't already know that recordable
CDs and DVDs don't age well. And yes, I took a sampling of the CDs and ran
them on 3 different players, 2 of which are known to read just about
anything. Can't track anything on any of them.




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[David Arnstein]

Thank you for confirming most of my prejudices regarding CD-Rs and
DVD-Rs.

More generally, I do not believe that archival storage methods are
available at a price that is within reach of ordinary individuals.

My solution is "live" backups:

* I have all of my data on one peecee, on internal disk drives.

* I back up all of this data to multiple, USB-connected disk drives.

The USB-connected drives are my backup media. I don't expect them to
function as archival storage. In particular, I rotate through them in
a repeating pattern, with one media change every two weeks. My theory
is that the act of writing to the backup media serves to verify their
continuing survival. The fact that I rotate through several media protects
me against even multiple hardware failures.

[b***@MIX.COM]

Post by David Arnstein
More generally, I do not believe that archival storage methods are
available at a price that is within reach of ordinary individuals.

Anybody tried M-DISC? I have not... US$20 for 100GB (plus perhaps
a compatible drive).

http://www.mdisc.com

Billy Y..

[Jeff Liebermann]

Post by b***@MIX.COM

Post by David Arnstein
More generally, I do not believe that archival storage methods are
available at a price that is within reach of ordinary individuals.

Anybody tried M-DISC? I have not... US$20 for 100GB (plus perhaps
a compatible drive)
http://www.mdisc.com
Billy Y..

I haven't tried those, but the Navy did and ran some rather brutal
tests:
<http://site.produplicator.com/downloads/Manuals/China_Lake_Full_Report.pdf>
Bottom line is:
None of the Millenniata media suffered any data degradation
at all. Every other brand tested showed large increases in
data errors after the stress period. Many of the discs were
so damaged that they could not be recognized as DVDs by the
disc analyzer.

I've had more CD/DVD drive failures than media failures so I guess I'm
the exception to the rules.

[Mike Stump]

Post by b***@MIX.COM

Post by David Arnstein
More generally, I do not believe that archival storage methods are
available at a price that is within reach of ordinary individuals.

Anybody tried M-DISC? I have not... US$20 for 100GB (plus perhaps
a compatible drive).

Counterpoint:

So, out of 100 disks, how many were tested as readable at the end of
their documented life span? What's that you say? 0? 0 out of 100,
is a horrible number. Wake me up when that number is 1 or more out
of 100.

[Julian Macassey]

Post by David Kaye
Not exactly on-topic, but there are all kinds of sysadmins here, so I
thought I'd drop a line or two about CDs.

snippo

Post by David Kaye
So, I'm going through boxes of the one-time backups ready to scratch the
surface or break the CDs in two before trashing them. No need to make them
unreadable -- they're ALL unreadable! I was careful to put the CDs and DVDs
on the floor of my closet where they wouldn't be exposed to heat or light,
which damages the dye used in recordable CDs. Well, not even the special
"lasts a lifetime" gold-colored CDs survived. Mind you, these are CDs and
DVDs I recorded once just as temporary backups; the latest in this batch is
from 2007, so it's no great loss for me.
I guess this is a reminder for people who don't already know that recordable
CDs and DVDs don't age well.

I'm sure there is some data storage sytem out there that can be put
in a vault and read in the future, but I don't know what it is.

The only data recoding medium I know of that lasts is punched paper
tape.

Punched paper tape probably doesn't have the archival lifetime of ink
on vellum.

Maybe we should put some monks to work on this archival problem.

[Tak Nakamoto]

"David Kaye" wrote:

"I guess this is a reminder for people who don't already know that
recordable
CDs and DVDs don't age well. And yes, I took a sampling of the CDs and ran
them on 3 different players, 2 of which are known to read just about
anything. Can't track anything on any of them."

------------

This post was a bit alarming to me. And since I'm taking a day to rest after
overexerting myself doing home repairs yesterday, I grabbed a sample of
CD-Rs that I burned in 2002 and tried to read them. I had five CDs handy of
that vintage and all of them read just fine. They were all name brand disks
and stored in individual envelopes in a home office environment. My CD-Rs
look good thus far.

I see that you tried reading your old disks on different players. Did you
burn those disks on several burners or did you use just one?

I found this article from 2012, in which the author tested 400 CDs burned
from '97 to '05 and was able to read all but 10 of them. The author thinks
that with more work he could read most of them too.

http://www.rlvision.com/blog/how-long-do-writable-cddvd-last-400-discs-put-to-the-test/


Tak Nakamoto

[David Kaye]

Post by Tak Nakamoto
I see that you tried reading your old disks on different players. Did you
burn those disks on several burners or did you use just one?

Two different units, neither of which I have anymore. I don't remember the
brands but they were top-notch OEMs such as Toshiba. The CDs were Sony and
Verbatim for the most part. The Verbatims had pre-applied labels which I
wrote on with Sharpies, so the Sharpie ink likely didn't penetrate below the
label itself.

Thanks for the link. I have a more recent USB unit which I'll also try as
soon as I find it.




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[David Kaye]

By the way, for my personal storage of data, programs I'm writing, music,
photos, etc., I use two USB 3TB HD drives. I copy to one and then back it
up to the other, so I have identical copies on each drive. My experience
with HDs has been that with the exception of a little surface failure,
generally the failures tend to be the motor or the stepper, usually the
stepper. With stepper problems it's usually possible to eventually read the
disk; it just takes forever and often unplugging and replugging the drive to
move the stepper back to home position.

So, I'm thinking seriously of ditching CDs and DVDs entirely and backing up
the temporary stuff to external SSD (64GB) or the larger HDs. I think I'll
get much better mileage from this method, and it'll be faster, too.




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[Jeff Liebermann]

On Wed, 23 Sep 2015 16:49:20 -0700, "David Kaye"

Post by David Kaye
So, I'm thinking seriously of ditching CDs and DVDs entirely and backing up
the temporary stuff to external SSD (64GB) or the larger HDs. I think I'll
get much better mileage from this method, and it'll be faster, too.

You may want to reconsider the SSD idea:
<http://www.pcworld.com/article/2921590/death-and-the-unplugged-ssd-how-much-you-really-need-to-worry-about-ssd-reliability.html>
I haven't seen any such failures, yet.

[David Kaye]

Post by Jeff Liebermann
<http://www.pcworld.com/article/2921590/death-and-the-unplugged-ssd-how-much-you-really-need-to-worry-about-ssd-reliability.html>
I haven't seen any such failures, yet.

Oh I agree. As I said I'll be using SSDs for temporary storage, that is
customer files that I need to transfer one place or another, in the same way
I used CDs and DVDs in the past. But for permanent storage I'm relying on
convential USB hard drives.

At first I was wary of the larger storage of 3TB drives. I had been quite
content with 200 to 500GB, thinking that the all the extra bytes still have
to fit in the 2 1/2 inch HD physical profile. So, obviously they've got to
make the sectors way smaller. How small is too small? Will a 3TB HD be as
reliable as a 500GB HD?




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[Jeff Liebermann]

On Thu, 24 Sep 2015 01:01:38 -0700, "David Kaye"

Post by David Kaye

Post by Jeff Liebermann
<http://www.pcworld.com/article/2921590/death-and-the-unplugged-ssd-how-much-you-really-need-to-worry-about-ssd-reliability.html>
I haven't seen any such failures, yet.

Oh I agree. As I said I'll be using SSDs for temporary storage, that is
customer files that I need to transfer one place or another, in the same way
I used CDs and DVDs in the past. But for permanent storage I'm relying on
convential USB hard drives.

You may have missed the point of the article. The problem is that
with no power applied and a warm SSD, the leakage currents increase
sufficiently to affect long term reliability. One article claimed
that it's possible to loose data in about a month, if power is not
applied. There are also a few high reliability SSD packagers, that
include a battery. I'm suppose to be giving a talk on SSD to the
local Linux user group next month and have accumulated a collection of
links on the topic. I'll post a few when I return to my office tonite
or tomorrow.

Incidentally, if you're thinking of hot swapping SSD drives:
"The mysteriously disappearing drive: Are power outages killing
your SSDs?"
<http://www.extremetech.com/computing/169124-the-mysteriously-disappearing-drive-are-power-outages-killing-your-ssds>

Post by David Kaye
At first I was wary of the larger storage of 3TB drives. I had been quite
content with 200 to 500GB, thinking that the all the extra bytes still have
to fit in the 2 1/2 inch HD physical profile. So, obviously they've got to
make the sectors way smaller. How small is too small? Will a 3TB HD be as
reliable as a 500GB HD?

I have no idea. Reading data off a hard disk drive has been somewhat
of a statistical exercise for at least 20 years. The days when you
can put an oscilloscope on the output of the head and actually see a
"1" or "0" are long gone. These days, the waveform looks like garbage
and the decision as to whether it's a "1" or "0" is an exercise in
decompression, error correction, and probability.

"How NOT to evaluate hard disk reliability: Backblaze vs world+dog"
<http://www.theregister.co.uk/2014/02/17/backblaze_how_not_to_evaluate_disk_reliability/>
There are quite a few good links and insights in this article on drive
reliability.
"Moral of the story: design for failure and buy the cheapest
components you can. :-)"
Obviously, you're not running a server farm and will not be beating
the drives to death. You're counting on the assumption that a lightly
used drive will last forever. That hasn't been my experience as I've
had DOA drives pulled out of old stock when trying to fix a RAID
array.


Drivel: Even pencil and paper are not reliable. More than one of my
customers refuse to inscribe their passwords in a speadsheet, text
file, or suitable program. They write them on the smallest piece of
paper they can find, using a pencil. The paper is then folded,
spindled, and mutilated until the scribbles are unreadable. When it
comes time to login to some account, it can't be read. When I demand
that they transcribble the pencil scratches into a spreadsheet, they
can't read their own handwriting, and just stop. The one customer
that actually did transcribble the scribble pad, managed to get the
upper/lower case letters all wrong. Last week, I had to use a
microscope and UV light in order to extract a password. I wouldn't
have mentioned this, except I have FOUR customers with exactly the
same bad habit. AAAAAAAAAAAAAAAAAAAAAAARGH!

[Jeff Liebermann]

Post by Jeff Liebermann
I'll post a few when I return to my office tonite
or tomorrow.

"Power Loss and Data Integrity in Military SSDs"
<http://www.aerodefensetech.com/component/content/article/adt/features/feature-articles/21172>

[John Slade]

Post by Tak Nakamoto
"I guess this is a reminder for people who don't already know that
recordable
CDs and DVDs don't age well. And yes, I took a sampling of the CDs and ran
them on 3 different players, 2 of which are known to read just about
anything. Can't track anything on any of them."
------------
This post was a bit alarming to me. And since I'm taking a day to rest after
overexerting myself doing home repairs yesterday, I grabbed a sample of
CD-Rs that I burned in 2002 and tried to read them. I had five CDs handy of
that vintage and all of them read just fine. They were all name brand disks
and stored in individual envelopes in a home office environment. My CD-Rs
look good thus far.
I found this article from 2012, in which the author tested 400 CDs burned
from '97 to '05 and was able to read all but 10 of them. The author thinks
that with more work he could read most of them too.
http://www.rlvision.com/blog/how-long-do-writable-cddvd-last-400-discs-put-to-the-test/

I find similar results with CDs and DVDs. I have CDs
that I burned in 2000 that still read fine. I stored them in
plastic shoe boxes and kept them in a dry place. I also found
that CDs stored in vinyl sleeves rather than paper seem to have
fewer problems. The CDs that I found that didn't work were the
CDs I didn't take care of, some of them were cheap and the top
surface just wore away. Some I would treat roughly and the top
surface got scratched. Others had tiny pinprick sized holes in
them but they read fine.

What probably helped my case was doing research. I got
info from professionals about what CDs were best for archival
purposes. But the best solution for backup for people on a
budget is to backup to enterprise class HDs then transfer to a
new drive every two or three years. Most of these HDs have five
year warranties and if used minimally to store backups they
should be fine for longer than three years. I just recommend
every few months powering up the drive for a few minutes. The
prices for enterprise drives have gone down greatly in the past
few years too.

John

[David Kaye]

What probably helped my case was doing research. I got info from
professionals about what CDs were best for archival purposes.

Okay, WHICH CDs are best for archival purposes? Obviously Verbatim and Sony
aren't, given that I've lost so many. And again, I stored them away from
heat and light in an area that never gets above 70 degrees even on warm
days.




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[John Slade]

Post by David Kaye

What probably helped my case was doing research. I got info from
professionals about what CDs were best for archival purposes.

Okay, WHICH CDs are best for archival purposes? Obviously Verbatim and Sony
aren't, given that I've lost so many. And again, I stored them away from
heat and light in an area that never gets above 70 degrees even on warm
days.

Actually I would recommend you use DVDs rather than CDs. I
haven't used CDs to store anything important since I switched to
DVDs. Here is a guide that may help you.

http://www.digitalfaq.com/reviews/dvd-media.htm

If you want CDs I have heard that Taiyo Yuden are good. I
haven't really done much thought about using CDs for archiving
anything as they are less durable than DVDs. I've used Verbatim
DVDs and Taiyo Yuden CDs without problems and the disks I burned
ten years ago read fine in both cases. You should also make sure
you keep the disks in a dry place. Many of my disks were stored
in a room where the temperature regularly reached 90 degrees so
I don't think heat is that much of an issue. Dramatic temp
changes over a short period is a lot more damaging at least
that's what I hear.

John

[David Kaye]

Actually I would recommend you use DVDs rather than CDs. I haven't
used CDs to store anything important since I switched to DVDs. Here is a
guide that may help you.

I used the term "CD" generically so that I wouldn't have to keep writing
"CDs and DVDs", but naturally you came back at me.

I'd rather not archive on DVDs or CDs because they're simply too small. I'd
prefer to store on something that's at least several hundred GB. That's
SSDs and HDs today.




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[Eli the Bearded]

Post by David Kaye
I'd rather not archive on DVDs or CDs because they're simply too small. I'd
prefer to store on something that's at least several hundred GB. That's
SSDs and HDs today.

Magneto-optical.

Uses a magnet to read, and a laser + magnet to write. Media looks like
old-school 3.5" floppies (until you look inside at least or you get the
high-capacity 5.25" ones which then look similar but much larger).

http://www.medgrade.com/browse.asp?Category=Drives:Magneto+Optical+Drives

My 128MB MO media -- now twenty years old -- are still read by modern
3.5" MO drives.

Elijah
------
expects no one else will be buying MO stuff

[d***@52.usenet.us.com]

Post by David Kaye
DVDs I recorded once just as temporary backups; the latest in this batch is
from 2007, so it's no great loss for me.

I have CDs written in the late 90's that are still readable.
I don't think I've ever had a CD failure.
I had one CD/DVD drive that failed in a maddening way, but I don't think
I've ever had media fail.
I just tossed a copy of an MSDN Windows2000 CD, but it still worked, last
time I tried, which was probably a year ago.
I purged all of my Redhat CDs back to AS 2.1, but they have all been used
several times over the years.