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You might want to check your CDRs!, One reason I don't backup to CDRs
TwoJ
post Feb 22 2004, 07:32
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Thought some people might find this interesting;

http://www.cdfreaks.com/news/7751

The original dutch article is here;

http://www.pc-active.nl/toonArtikel.asp?artikelID=508

To condense
QUOTE
thirty different CD-R brands, that were recorded twenty months ago. The results were quite shocking as a lot of the discs simply couldn't be read anymore
crying.gif

While no storage media is garenteed, I'm taking my chances with hard drives.
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Sid59
post Feb 22 2004, 07:39
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the article doesn't cite how those CD-Rs are stored. That could play a huge part into how the CD-R handles the '20 months'. Recently i had my hard drive die and i lost my collection of music. ALL of it is backed up on CD-R or DVD. The oldest CD-R i have date back to EARLY 1999 - around April. I used unmarked cheap media, Sony, Memorex, Fuji and ALL of THEM READ AND TRANSFER without a hitch. I recovered EVERY SINGLE file that i backed up. Not a problem. I store some cds in a CD Book and the rest on a spindle. The CD Book and spindle sit in my closet.
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MugFunky
post Feb 22 2004, 14:48
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maybe i'm not looking at the right pages, but where are the stats?

there's nothing in that article except to say "not even name brands survived our undisclosed methodology"

this article appears completely alarmist to me, and doesn't offer me any alternative to using CD-R (we've all seen hard disks happily carve the sectors off themselves before i'm sure). of course i've had good discs turn to coasters in a matter of 4 months before, but they are in a clear minority, and most probably more dependant on the equipment used to burn them.

of course, i might have missed a link somewhere (i brushed over the dutch article and didn't see anything that indicated a page of brands used and errors found, but i can't read dutch.)

hehe. was this a blind test? smile.gifsmile.gif

This post has been edited by MugFunky: Feb 22 2004, 14:50
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Pio2001
post Feb 22 2004, 16:02
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I didn't take the time to translate the article, but I understood that it was the summary of an article published in a magazine.

Here is the HA thread for dead CDRs : http://www.hydrogenaudio.org/forums/index....howtopic=17718&
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MugFunky
post Feb 23 2004, 07:17
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ah. good call. that makes it a tad more credible. wish there was a link to some results, but i guess to find out what did best/worst you have to buy the magazine tongue.gif
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kennedyb4
post Feb 24 2004, 02:42
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QUOTE (Sid59 @ Feb 22 2004, 01:39 AM)
the article doesn't cite how those CD-Rs are stored. That could play a huge part into how the CD-R handles the '20 months'. Recently i had my hard drive die and i lost my collection of music. ALL of it is backed up on CD-R or DVD. The oldest CD-R i have date back to EARLY 1999 - around April. I used unmarked cheap media, Sony, Memorex, Fuji and ALL of THEM READ AND TRANSFER without a hitch. I recovered EVERY SINGLE file that i backed up. Not a problem. I store some cds in a CD Book and the rest on a spindle. The CD Book and spindle sit in my closet.

I have a number of svcd and divx movies burned on various media.

Those burned on Kodak golds and silver/golds all work flawlessly.Some are 5 years old.

Those recorded on verbatims and memorex (Ritek?) cds have serious skipping problems and have crc checksum failures and are now useless. Some are less than 6 months old.

How much does this have to do with laser calibration?

I have always wanted a prog that would give me manual control of the laser power for various media.

PS - they are all stored in a cool dry location in the original cases. They come out to get played maybe twice or three times a year for favourites.

This post has been edited by kennedyb4: Feb 24 2004, 02:44
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CiTay
post Feb 24 2004, 03:29
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QUOTE (kennedyb4 @ Feb 24 2004, 02:42 AM)
I have always wanted a prog that would give me manual control of the laser power for various media.

You can do that with a Plextor and the "VariRec" function. Contrary to Plextor's claims though, c't found out that using it always increases jitter.
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bidz
post Feb 24 2004, 03:38
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Weird stuff. I Can't understand that media just "dies" after a few months.. I've burned thousands of CD-R's the last years, and hey.. all of them i have tested still works perfectly. Smart-Buy, Verbatim, Samsung, Trax-Data, Sony, BASF/Emtec, Imation, Mr. Platinum + more. I usually always buy the cheapest spindle i find smile.gif

I've only used Plextor burners though. Maybe they are "King Of Quality" afterall wink.gif

Oh yea, and i also just have the spindles laying around wherever i feel like it.. mostly on my desk, in a closet, in cd-cases, or whatever..

Maybe it's the temperature here in Norway. It ain't all that hot here, and the air is rather dry, heck if i know, or care smile.gif

This post has been edited by bidz: Feb 24 2004, 03:42


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ger@co
post Feb 24 2004, 04:30
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Here is a list of Taiyo Yuden claims.

QUOTE
Features:

*Up to 48X CD Recording speeds are supported
*"Super Cyanine" dye provides zero wave distortion
*Compatibility with all CD recorders and duplicators is assured
*BLER,E-12, and E-22 errors are the lowest in the industry
*Jitter and Deviation levels are the lowest in the industry
*Proprietary printable surface media provides professional looking graphics and text on the media surface
*Data integrity is guaranteed to 100 years
*Intensive quality assurance methods are in place during the manufacturing process, providing industry leading yield rates


I don't think that any of us will live long enough to validate the longevity of their discs. biggrin.gif

Later.

The original page can be viewed here.

This post has been edited by ger@co: Feb 24 2004, 04:34


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TwoJ
post Feb 24 2004, 06:08
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I did get the impression that the article was a bit alarmist, and 2 years is pretty short, considering that the vast majority of my 2 year & plus CDRs are perfectly readable.
Nevertheless I still believe it is a higher risk media than hard drives, plus I don't like the fact that you cannot alter the information, and at some point backing up 120GBs of data to 700 MB CDs becomes a tiresom event.

How do you guarentee data integrity? What happens if the file is unreadable will they magically give you the data back? No doubt they make good CDRs - what I would buy if I was doing backup - but that claim just seems riduculous.

Anyhow, I am still happy with backing up to HDs. I would hate to think the # of hours I would have to spend and the hundreds of CD needed to store that data, plus the time to check them, etc, etc.
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westgroveg
post Feb 24 2004, 06:54
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QUOTE
I don't like the fact that you cannot alter the information

This is one of most critical things, nothing can alter the data, no virus, not an OS bug or error, overwriting (users, programs even with read-only this can happen) or even hackers (RIAA wink.gif ) not to mention that HD's have mechanical parts which make it even more risky.

I think the CD-R format gets a bad name because of bad media brands, recorders, storage conditions, easy physical damage, CDA. Be cautious what you use but in my opinion it's still wise to make CD-R back-up of your data.

This post has been edited by westgroveg: Feb 24 2004, 08:52
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dreamliner77
post Feb 24 2004, 10:14
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I'm starting to come to the conclusion that the physical burner is more important than the media.

I've had a LG 8120B (12x) for the past 3.5 years and I have yet to have any discs it burned become unreadable. The only ones that show errors are the ones that have spent time in my car. I've used CMC, TY, RITEK, Mitsubishi and Maxell.

I just put in a Lite-On 52x and all seems good, except that CMC discs tend to get a few (3-20) errors on the very outside of the disc if I burn 40x+.


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Pio2001
post Feb 24 2004, 12:38
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QUOTE (ger@co @ Feb 24 2004, 04:30 AM)
QUOTE
Features:
Data integrity is guaranteed to 100 years


I don't think that any of us will live long enough to validate the longevity of their discs. biggrin.gif

Mitsui media claims Up to 100 years longevity, and many of us have burned for long enough to see them die.
http://www.mitsuigold.co.uk/web/cd-r_80_mi...mb_golden.phtml
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ger@co
post Feb 25 2004, 08:33
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Of course, we have. That was simply my lame attempt at humour. biggrin.gif

Later.


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rohangc
post Feb 25 2004, 09:05
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Here is a comprehensive guide (more than 50 pages!!!) to preservation of digital material (read CDs and DVDs) by NIST. Here is a one page summary of the guide itself. Most of it is not unknown to us and is just pure common sense. However it makes an interesting read. We may just be able to extend the life of those CD-Rs at least a little by following what's given here.

This post has been edited by rohangc: Feb 25 2004, 09:06
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Halcyon
post Feb 25 2004, 10:13
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This discussion crops up every now and then and I'm sad to say that collectively we are not much wiser with each discussion.

My personal summary of own experiences and relatively extensive research onto the subject (most publicly available media longevity studies, discussion with researchers, etc.)

- I have burns from 1994-1995 that still read flawlessly and measure really low with kProbe (I'm agry at myself for having thrown out the stuff from -91, because the material was useless. The scans would have been interesting).

- I have burns that are just 2 months old that are now dead, even though they initially measured nicely with kProbe (not the worst media, but not the best either)

- Even the "best" media can fail: Fuji has been (and still is) very prone to UV radiation. I've had Kodak Gold's peel themselves after two years. Some batches have problems with lamination and grease or oxidisation attacks them really fast, etc.

- Hence, at leats not all manufacturer claims are to be trusted when it comes to disc longevity.

- One can increase the probable lifespan of a disc by following some basic rules of thumb.

- Use only high quality manufacturer discs (TY and MCC are decent bets for many modern & new burners today. Extra protection on the label side doesn't hurt. e.g. Verbatim Crystal and Data Armor discs)
- Use only high quality burners and measure the burns. Discard burns with relative high amount of read errors in reading (even if they are still readable)
- Store in a stable and relatively cool (not fridge or anything as cold!), dry, dark place & away from noxious gages. Avoid changes in relative humidity/temp.
- handle with care, avoid scratches, avoid dirt & grease from hands. Don't force discs to high physical stress. Avoid contacts with fluids.
- when reading, use readers that are not broken or at the end of their lifespan. Consider using lower rotational speeds than what 48x / 52x speeds require. In most cases 12x-16x is plenty enough for reading and stresses discs and readers much less.
- don't use markers on the data area of disc (either side), definitely don't use stickers or print-on-labels (the adhesives of which hasn't been properly studied)
- Periodically test and re-back up your data to new discs. For highly important unique materials, store in two different places separately
- For extra high valued data, consider using a burning program that puts another layer of error correction data on the disc (you lose some data storage space, but you gain more reliability against random errors)

I might add that the the jury is out on DVD longevity as well. The situation is very much unknown. Some accelerated media aging preliminary studies don't paint a pretty picture.

I'm really waiting for dual layer dvd-burning systems with a mixed sense of joy and horror. I'm afraid the first batches of both burners and discs will be utterly useless of any kind of long term data archival.

regards,
Halcyon

PS I've been meaning to write an article about this for the past year and a half. However, every single time I think I've understood the subject enough, more interesting things come up or there are further delays in my test setup. I don't claim to be an expert on this subject (far from it, actually), but I know enough already to understand that the issue is not clear cut or simple.
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Lev
post Feb 25 2004, 10:32
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QUOTE
QUOTE
*Data integrity is guaranteed to 100 years

I don't think that any of us will live long enough to validate the longevity of their discs.

Oh, I will wink.gif

Having only bought dirt cheap media for testing purposes (or for throwing at mates - sometimes literally), and 'decent' for my actual use, I have no dead discs, in fact no discs with errors (ok, I dont check EVERY CD all the time, but I do play a huge variety of them), and some of them are now ~7 years old smile.gif


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britannica
post Feb 27 2004, 13:35
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QUOTE (Halcyon @ Feb 25 2004, 09:13 AM)
  - For extra high valued data, consider using a burning program that puts another layer of error correction data on the disc (you lose some data storage space, but you gain more reliability against random errors)



I'm using the OEM Nero 5.5 that came with my CDRW which does a verification pass...what burning programs give a better level of error correction ?
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Halcyon
post Feb 27 2004, 18:04
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I think there are several utilities, but I can't remember any of them off-hand smile.gif

A quick Google search revealed nothing, but I'm sure there is a "for sale" Windows program that generates an additional application level error correcting codes for your data and saves them on the cd along with your data.

It's useful in the sense that the disc / file format is completely standard (i.e. you can read it in any drive / OS supporting standard ISO cd-formats). If you want to get the extra error correction codes added reliability, by using the burning program to read the data off the disc. Of course, if the additional error correcting data part of the disc is destroyed beyond repair, then you lose that additional level of correction as well.

An alternative for Linux (under development) appears to be CDProtect at:

http://www.inf.tu-dresden.de/~hs3/software.html

Note, I have not tested these utilities to verify that they actually work. But the basic approach is sound.

Of course, there are additional "tape centric" / image based software that put one lump (or part of a stream) of data on your CD-R, but you will always need the burning program in question, to read the data off the disc properly. Well not always, as some use standard Unix/Linux utilities, but you get the point.

best regards,
Halcyon
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JeanLuc
post Feb 27 2004, 18:35
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QUOTE (Halcyon @ Feb 25 2004, 09:13 AM)
I'm really waiting for dual layer dvd-burning systems with a mixed sense of joy and horror. I'm afraid the first batches of both burners and discs will be utterly useless of any kind of long term data archival.

Hey, we haven't even reached the point where we can safely assume that single-layer DVD writing will lead to decent results without the need of much personal research for working burner/media combinations (see the media-hardware-related threads over at cdfreaks) ... so from my point of view, dual layer DVD comes way too early, as well as 16x DVD burning ... blink.gif

There are exactly two pieces of DVD media (TY +R & Ricoh +RW, that is) that meet my expectations with my LiteOn 411S regarding PI/PO values and thus headroom for future media degradation ...


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kennedyb4
post Feb 28 2004, 04:02
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QUOTE (CiTay @ Feb 23 2004, 09:29 PM)
QUOTE (kennedyb4 @ Feb 24 2004, 02:42 AM)
I have always wanted a prog that would give me manual control of the laser power for various media.

You can do that with a Plextor and the "VariRec" function. Contrary to Plextor's claims though, c't found out that using it always increases jitter.

If it jitters,does that mean the risk of smaller errors occuring on playback? Would that be something a person could live with?

I would way rather have that from an aging burner than certain death of the disk.
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Halcyon
post Mar 8 2004, 10:15
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QUOTE (JeanLuc)
Hey, we haven't even reached the point where we can safely assume that single-layer DVD writing will lead to decent results without the need of much personal research for working burner/media combinations


I completely agree. See my posts at cdrlabs forum smile.gif

QUOTE
There are exactly two pieces of DVD media (TY +R & Ricoh +RW, that is) that meet my expectations with my LiteOn 411S regarding PI/PO values and thus headroom for future media degradation ...


You might want to be careful with those kProbe scans and trusting those Pi/Po values: error rates in one configuration (drive/firmware/cpu speed) for one reading (reading speed/certain amount of material burned/kProbe settings) are not always the same for another configuration.

However, if you pick a reliable enough burner and measure the LOW LEVEL data from the disc (not pi/po errors), then you can actually deduce something useful out of the test for long term readability and initial write quality.

It is already known that one can make very misleading results (too good or too bad) and as such they should not be the final (or only) measure of burner/media compatibility and probably future readability.

Another possibility is using various drives, with various software and cross-referencing these with known low level measurements from both the drives (both burners and readers low level performance) AND the media (scans from a professional low level quality analyzer).

However, the latter is still to be tried out by the hobbyist community. Unfortunately a blind faith in kProbe PI/PO scans seems to have taken over many (not claiming you are) and we should be careful about propagating this myth any further.

regards,
Halcyon
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