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Think its safe to trust your precious memories on DVD Recordable Discs?
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bellario
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21. May 2006 @ 01:36 |
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Dear All,
This is part of my effort to bring the issues of DVD recordable disc degradation/deterioration to the knowledge of everyone in the world.
I have started off the effort in April of 2005 and it has been almost a year now. Since that date, I have amassed a considerable amount of information, from results of my own testing, to reports of DVD recordable disc failures by other end users, research studies by independent laboratories, foreign magazines, press and media. All of the information could be found in the following Central Database:
http://forums.hardwarezone.com/showthread.php?t=991675
There is so much information in it that you could practically call it a database. I will post references/links here in this thread whenever I update the database with new information.
Sadly, the majority of the DVD recordable discs on the market are not very reliable or durable. The lifespan or longevity of these discs after burning is typically 2-3 years. In fact, this problem is so critical that it has warranted research studies by the National Institute of Standards and Technology and the Library of Congress. NIST has been working with the industry and the user community to develop a standard methodology for determining archival quality grade discs. Due to this effort by the NIST and the Library of Congress, some manufacturers have released Archival Grade DVD Recordable Discs recently, though such discs are still unproven.
Hence, please think twice before entrusting any important data to DVD recordable discs, and do have secondary backups if possible. For more information, please read the above-mentioned database.
The dominant cause of disc failures in Singapore is high humidity, though many other facts can also affect the longevity of dvd recordable discs.
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guyrus
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22. May 2006 @ 00:05 |
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hey bellario, this debate and experimentation has been going on for a few years now.Originally the manufacturers told us all that 100 years was the go and now they have backflipped and 2-3 years you need to re burn those precious memories.I think in time as this industry is still in its infantcy they will fix this minor issue but once fixed i;m sure the cost of the discs will increase as well.
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bellario
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25. May 2006 @ 09:47 |
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Disc test results which were previously lost have been restored on pages 62, 63, 64.
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bellario
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25. May 2006 @ 19:08 |
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Memorex, a manufacturer of DVD recordable discs, has openly admitted that DVD recordable discs are far more sensitive to humidity than CD-R discs in environmental tests, in its whitepaper on lifetime expectations on optical discs, dated March 2006. This means that DVD recordable discs have a much shorter lifespan compared to CD-R discs.
To know more, please refer to Page 65, post #964 or click on the following link:
[url]http://forums.hardwarezone.com/showpost.php?p=18747116&postcount=...
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bellario
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26. May 2006 @ 21:01 |
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Please pass on the above message to your friends and relatives to let them know that if humidity problems are not handled properly, they could lose their data.
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guyrus
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26. May 2006 @ 23:11 |
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thats probably true but cant be the only reason, for the limites life span
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bellario
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9. June 2006 @ 23:26 |
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Page 65 and Contents Page updated with new information.
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Senior Member
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10. June 2006 @ 03:06 |
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Very interesting read, an awful lot of info there, I do appreciate you posting this. Thanks.
Outside of a few DVD going bad, primarily from the less quality minded manufacturers, I haven't had a problem after 3 years, but this is still within the envelope of acceptability as far as the manufacturers state, what will the next three years bring??
This message has been edited since posting. Last time this message was edited on 10. June 2006 @ 03:08
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guyrus
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10. June 2006 @ 12:06 |
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the nxt 3 years will probably be a test to see if they can stand the ravages of time............then its any ones guess
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bellario
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12. June 2006 @ 03:49 |
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PDF e-books on DVD Longevity / Lifetime / Degradation are now available for offline reading.
[1] Really Disappointed with DVD Discs Media
Filename: ebook.zip
Filesize: 124 MB
Version: 11 June 2006
Last Page of e-book: 66
md5sum: 35933fe5c7de68576f53fd41bdbcfd68
Download Link:
http://s5.quicksharing.com/v/5678953/ebook.zip.html
[2] Experimental Data on DVD Longevity
Filename: ebook.zip
Filesize: 9 MB
Version: 10 June 2006
Last Page of e-book: 13
md5sum: 45de8c4fb00fce89c7870adf86a884f8
Download Link:
http://s7.quicksharing.com/v/9697463/ebook.zip.html
[3] The Unofficial HWZ Surviving DVD Media Durability Scan Thread
Filename: ebook.zip
Filesize: 36 MB
Version: 11 June 2006
Last Page of e-book: 12
md5sum: 046cf448bb82ee92cff1c2641567eb95
Download Link:
http://s3.quicksharing.com/v/2936697/ebook.zip.html
***Please verify the md5sum of the file that you have downloaded to ensure that you have downloaded the correct file.
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bellario
Suspended due to non-functional email address
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15. June 2006 @ 21:13 |
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PDF e-books on DVD Longevity / Lifetime / Degradation are now available for offline reading.
Please note that there are some broken links in the previous versions (10 & 11 June 2006) of e-books. These broken links have been fixed in the current version (15 June 2006). All hyperlinks in PDF files should work now.
The filesizes are so much smaller now and should take less time to download. The current version of e-books also features full color graphics.
[1] Really Disappointed with DVD Discs Media
Filename: ebookv2.zip
Filesize: 46 MB
Version: 15 June 2006
Last Page of e-book: 66
md5 checksum: c00a736c524499d1f8fb70c20229fde6
Download Link:
http://s9.quicksharing.com/v/5379432/ebookv2.zip.html
[2] Experimental Data on DVD Longevity @ cdfreaks
Filename: ebookv2.zip
Filesize: 2.55 MB
Version: 15 June 2006
Last Page of e-book: 13
md5 checksum: 55957ac5fb56084f28b14e3134766bd6
Download Link:
http://s2.gimehost.com/v/5434801/ebookv2.zip.html
[3] The Unofficial HWZ Surviving DVD Media Durability Scan Thread
Filename: ebookv2.zip
Filesize: 10 MB
Version: 15 June 2006
Last Page of e-book: 12
md5 checksum: 14652c226020be65d3f41e46ac9033e2
Download Link:
http://s9.quicksharing.com/v/4618437/1ebookv2.zip.html
***Please verify the md5 checksum of the file that you have downloaded to ensure that you have downloaded the correct file.
There are some minor issues in viewing the latest version (15 June 2006) of the e-books with Adobe Reader 6.0 and 7.0.
In some PDF files, Adobe Reader will report "A drawing error occurred.".
You may want to try the FREE Foxit PDF Reader 1.3. I have tested it and there should not be any problems in viewing the PDF files.
To download the Foxit PDF Reader, click on the following link:
http://www.foxitsoftware.com/download.htm
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AfterDawn Addict
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15. June 2006 @ 21:22 |
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i agree use tape..
Burned CDs Last 5 years Max -- Use Tape?
Posted by CmdrTaco on Tuesday January 10, @11:16AM
from the been-there-before dept.
Data Storage
Lam1969 writes "Computerworld has interviewed Kurt Gerecke, an IBM storage expert and physicist who claims burned CDs only have a two to five-year lifespan, depending on the quality of the CD. From the article: "The problem is material degradation. Optical discs commonly used for burning, such as CD-R and CD-RW, have a recording surface consisting of a layer of dye that can be modified by heat to store data. The degradation process can result in the data 'shifting' on the surface and thus becoming unreadable to the laser beam." Gerecke recommends magnetic tapes to store pictures, videos and songs."
Storage expert warns of short life span for burned CDs
And don't count on hard disk drives for long-term storage, either
News Story by John Blau
JANUARY 10, 2006 (COMPUTERWORLD) - Although opinions vary on how to preserve data on digital storage media, such as optical CDs and DVDs, Kurt Gerecke, a physicist and storage expert at IBM Deutschland GmbH, takes this view: If you want to avoid having to burn new CDs every few years, use magnetic tapes to store all your pictures, videos and songs for a lifetime.
"Unlike pressed original CDs, burned CDs have a relatively short life span of between two to five years, depending on the quality of the CD," Gerecke said in an interview this week. "There are a few things you can do to extend the life of a burned CD, like keeping the disc in a cool, dark space, but not a whole lot more."
The problem is material degradation. Optical discs commonly used for burning, such as CD-R and CD-RW, have a recording surface consisting of a layer of dye that can be modified by heat to store data. The degradation process can result in the data "shifting" on the surface and thus becoming unreadable to the laser beam.
"Many of the cheap burnable CDs available at discount stores have a life span of around two years," Gerecke said. "Some of the better-quality discs offer a longer life span, of a maximum of five years."
Distinguishing high-quality burnable CDs from low-quality discs is difficult, he said, because few vendors use life span as a selling point.
Hard-drive disks also have their limitations, according to Gerecke. The problem with hard drives, he said, is not so much the disk itself as it is the disk bearing, which has a positioning function similar to a ball bearing. "If the hard drive uses an inexpensive disk bearing, that bearing will wear out faster than a more expensive one," he said. His recommendation: a hard-drive disk with 7,200 revolutions per minute.
To overcome the preservation limitations of burnable CDs, Gerecke suggests using magnetic tapes, which, he claims, can have a life span of 30 to 100 years, depending on their quality. "Even if magnetic tapes are also subject to degradation, they're still the superior storage media," he said.
But he's quick to point out that no storage medium lasts forever and, consequently, consumers and business alike need to have a plan for migrating to new storage technologies.
"Companies, in particular, need to be constantly looking at new storage technologies and have an archiving strategy that allows them to automatically migrate to new technologies," he said. "Otherwise, they're going to wind up in a dead end. And for those sitting on terabytes of crucial data, that could be a colossal problem."
http://computerworld.com/hardwaretopics/storage/story/0,10801,107...
Knowing your data will be there when you go back to it days, months, or even years later--well, that's a bit harder. Not all discs are created equal, as Fred Byers, information technology specialist at the National Institute of Standards and Technology, can attest.
Byers is part of a team heading up an independent study of DVD media quality. Based on the first wave of testing results, the situation is murky at best.
"We've found the quality varies, depending upon the type of dye used to make the write-once discs and [on the] the manufacturer," reports Byers. Even discs from the same manufacturer, with the same brand, can test differently, Byers adds. "But there was more of a significant difference when you compared discs between manufacturers," he explains.
DVD Media Quality: The First Tests
In the first phase of testing, completed late last year, NIST focused on the most popular media: write-once, single-layer DVD-R and +R discs. Rewritable discs will be tested in the second phase, slated to start this fall. An interesting footnote to the study's methodology: NIST uses media purchased off store shelves and via Web sites; and while researchers are tracking the media by brand, they are not tracking the specific factory source of the media tested. For example, a given manufacturer's discs could originate from different production lines, which could account for a variation in disc quality by the same manufacturer.
Hearing that there's a difference between the generic, unbranded 100-spindle value-pack of media purchased online and the branded offerings you might find on a Best Buy store shelf is not surprising. After all, as David Bunzel, president of the Optical Storage Technology Association, points out: "With a generic product, there's no consumer recourse. It's buyer beware."
If a disc isn't properly manufactured, the consequences can be dire. At best, the disc will fail immediately during the burn process; this is a best-case scenario because then you know from the start that the disc is faulty. At worst, you may get an abundance of errors during the burn process. These errors won't interrupt the burning process, and since write-once and rewritable DVD media have built-in error correction to compensate for scratches and other abnormalities on the disc (as do their CD cousins), any errors will be virtually invisible to you. You'll only know they're there if you use a disc diagnostics program, such as those offered by Ahead Software or Plextor. Nor will these errors affect the playback of the disc--initially.
Down the road, however, such invisible-to-the-eye errors can reduce the effectiveness of a DVD's built-in error correction so that if some other issue develops on your disc, such as a scratch, you could end up with an unreadable disc when you go back to it months or years later.
But what would cause such a wide disparity in media quality between branded discs from the same vendor?
"We don't know why it's different--it could be a different dye, it could be a different manufacturing process," notes Byers. "Manufacturers are constantly trying to improve their dye formulas--in theory improving the disc."
Nonetheless, at the same time, competitive forces are driving manufacturers to find ways to economize on production costs. And cost-cutting measures can result in discs that don't perform as well as those generated during an earlier production run, either in terms of failing outright or not burning at the maximum possible speed on a given DVD drive. "It varies over time, as the output changes," Byers says.
Brand Disparity
As for the disparity between brands that NIST found, the distinguishing factors come down to quality control and the dyes used in disc production. Declining to name names, Byers points out that "some manufacturers make their own discs, and some purchase them from someplace else--which opens you to variations in the manufacturing plant, or changes in the source [of that media]."
Vendors like Maxell and Verbatim manufacture discs on their own production lines, as do Asian manufacturers CMC Magnetics, RiData, Taiyo Yuden, and others; other name brands contract with a third-party manufacturer to produce discs to their own specs; and still others just buy third-party-produced media wholesale, without imposing their own set of quality controls on the media production.
The intricacies of disc production and quality control aren't the only variables that seem to affect media. More surprising is the number of discs that seem to have a propensity for specific hardware.
"One thing we've found in compatibility testing [of DVD-R and +R media] is that it's a relationship between a specific brand of media and the manufacturer of the hardware," observes Byers. "There was no one drive that played every single type of compatible media, and there was no one media brand that played perfectly in every drive."
And, he adds, sounding as frustrated as any consumer might, "You can't say there's a clear, delineated set of reasons as to why."
A Grading System?
One of the most common questions I hear is, "What's a good brand of media to buy?" DVD and CD media are so commonplace nowadays that it's easy to forget the complexities that go into producing them. And if anything in that production process is off, it could, in time, affect the integrity of the data you've burned to a disc.
"It's very tough to answer that kind of question, because there are so many variables," says Byers. "You don't get 100 percent yield when you manufacture these discs. We can talk about the materials that produce a good disc, but it also has to do with the manufacturing process. So, just to say the materials to look for doesn't necessarily relate to it being a better disc." The same is true vice versa.
So how can you know that the media you're using will last you for the duration, so those archived photos will still be there when you go back to a disc 20 years from now--or more?
For the moment, you can't. All DVD and CD vendors make vague claims about disc life expectancy being somewhere between 60 and 100 years--when the discs are treated with care and stored properly.
But NIST's Byers is seeking to change that. At an OSTA meeting in San Francisco this week, Byers is proposing an industry-wide grading system to indicate disc quality.
Byers is motivated by the desire to see a uniform mechanism in place to guide institutions and individuals who'll be storing data, music, videos, and images for long periods of time. "They need to be confident in their purchasing, so they can plan for their strategies in storing their information," Byers says. "Long-term storage has different meanings: For some, 30 years might be enough. For others, 50 or 75 years might be archive, or long-term, quality."
Longevity
Under Byers's proposal, a series of tests would be developed to determine whether a DVD would last for a given number of years. "If you were to purchase a disc in a store with a grade that indicates it has passed a test to last X number of years, it removes a lot of uncertainty for the consumer, and it can save some expense in premature migration [to a new storage technology], or loss of data because they waited too long [and the disc was no longer playable]," he says.
Although some archivists--both individual and professional--are concerned about whether today's digital storage mediums will be readable 50 or 100 years from now, Byers believes the bigger concern for users will be when to migrate their data to the next technology, "before the existing technology is obsolete."
The Disc Rot Myth
Media obsolescence isn't the only thing people fear after committing a personal library's worth of data to CDs and DVDs. But some worries--namely, fear of disc rot--are not fully warranted.
Like a bad seed, the myth of disc rot self-perpetuates, cropping up every now and again as a sudden and mortal threat to your copious collection of prerecorded and self-created discs.
The myth was once rooted in fact. It is true that back in the 1980s, with the first generation of prerecorded audio CDs, the edges of the discs were not always sealed properly, which allowed moisture to get into the disc. Replicated, prerecorded discs use aluminum for the reflective layer; when moisture came into contact with the aluminum on prerecorded discs, explains Byers, it in turn oxidized, causing the aluminum to become dull. "That's where the term 'rot' started," he says.
But that problem was quickly identified and overcome. "The manufacturers learned what was going on, so now the edges of discs are sealed with a lacquer," according to Byers. Though the problem is typically associated with CDs, Byers notes that the potential for interaction with oxygen is the same with both CD-ROMs and DVD-ROMs.
The so-called rot issue does not apply to recordable discs. For one thing, recordable optical media do not use aluminum; instead, they use silver, and very rarely gold, or a silver-gold alloy, for the reflective layer. "If the silver comes into contact with sulfates [i.e., pollution, or high humidity], it could affect the silver, but the likelihood of that is less than the likelihood of moisture coming into contact with the aluminum on prerecorded discs," says Byers.
Enduring Myth
The term rot has persisted, however inaccurately, as a means of identifying a plethora of problems with optical discs. "If you get a faulty disc and see a problem that you can visually see, you call it rot, but it could be the way the disc was manufactured," says Byers. "Or if it was subjected to extreme moisture and that moisture came into contact with the aluminum, it could be that the reflectivity has changed. It's not really rot, it's oxidation of aluminum. It should be a rare event on a disc, unless it's defective."
Beyond the realm of defective discs, improper handling can cause otherwise good discs to go bad. Since there's little protection between the label side of a CD and the data layer itself, "scratches on the label side can scratch the metal, and that will ruin the data," says Byers. It's not an issue for DVDs, though, since the dye layer is sandwiched between two plastic layers.
Byers observed a similar problem occurring with press-on labels: "For long-term storage, we recommend not using press-on labels on CDs; when these start to dry up, they can peel the metal right up, damaging data."
Have you experienced oddities with CDs and DVDs--whether you've recorded them yourself, or purchased them years ago? If so, tell us your story--including what kind of disc it was, when the problem first surfaced (and during what activity), how old the disc was.
http://www.pcworld.com/news/article/0,aid,116473,00.asp
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AfterDawn Addict
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15. June 2006 @ 21:24 |
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also more info in pdf
http://mediasupply.com/home/WSJ-Portals.pdf
more info here
Optical disks might not last as long as you would expect?or hope
http://www.gcn.com/print/23_5/25166-1.html
Breaking point
By Joab Jackson, GCN Staff
Story Tools: Print this | Email this | Purchase a Reprint | Link to this page
Optical disks might not last as long as you would expect?or hope
Don?t be mistaken: Optical disks won?t last forever.
Many users think the disks are indestructible, but they are wrong, said Fred Byers, an IT specialist at the National Institute of Standards and Technology.
As the government saves more and more records in electronic format, long-term archiving becomes a puzzle. Paper has lasted for centuries. Can optical disks really last for the 100-year life span envisioned for them?
The good news from NIST is that certain types of optical disks might last that long or even double that?but only if handled with care.
But disk life expectancy depends on many factors, some controllable by users, others not, Byers noted in a disk care guide, NIST Special Publication 500-252.
To test a CD?s endurance, NIST?s Byers ages the disk rapidly in a special environmental chamber.
To test a CD?s endurance, NIST?s Byers ages the disk rapidly in a special environmental chamber.
Image: J. Adam Fenster
The National Archives and Records Administration requested the report, asking NIST to come up with care and handling instructions for optical media. The goal was to imitate a report about magnetic tape care created by the now-defunct National Media Laboratory. Byers said he spent about a year testing disks and working on the guide.
Although many agencies have no archiving policy, they nonetheless are saving a lot of data on optical disks. ?There are a lot of questions about the implications of that,? Byers said.
Recordable CDs and DVDs can be as reliable as magnetic tape for backup, he said, and they read much faster because they use random access, whereas users must search files stored on tape sequentially.
The useful life span of optical disks varies with temperature, humidity and day-to-day use. Data degradation at first can go unnoticed because of the error-correcting abilities of disk readers.
NIST has found that recordable disks seem to last much longer than rewritable disks, Byers said, and even longer than manufactured disks such as CDs for installing commercial software.
General industry guidelines now estimate office-burned copies of CDs and DVDs could remain readable for 100 to 200 years.
A disk burner records information by laser-heating a dye inside the disk. Over time the dye fades, rendering the information difficult to read. The disk?s reflective layer, which sends information back to a photosensor during reading, is also subject to degradation.
Byers gets an up-close look at how the surface of a disk is holding up to the torture tests in a NIST lab.
Byers gets an up-close look at how the surface of a disk is holding up to the torture tests in a NIST lab.
The reflective layer is usually of thin gold, silver or silver alloy. Gold does not corrode, though gold-coated disks are expensive. Silver corrodes when exposed to air pollutants such as sulfur. Most silver-coated disks use alloys to inhibit corrosion.
Rewritable CDs and DVDs have a shorter life span of about 25 years, so Byers said he does not recommend them for archiving. A rewritable disk?s metal-alloy data layer is less stable than that in write-once disks. And rewritable disks are affected by light, so they also have a limited number of reads?a number that?s still uncertain.
Surprisingly, premanufactured CD-ROMs and DVD-ROMs may not last as long as recordable disks, Byers said. Surprisingly, premanufactured CD-ROMs and DVD-ROMs may not last as long as recordable disks, Byers said.
Most industry estimates place the life span of professionally produced optical disks somewhere between 20 and 100 years. But the weakness of the ROM disks stems largely from their aluminum reflective layer, Byers said.
When exposed to humidity and atmospheric oxygen through scratches, cracks or delaminated areas in the label, the aluminum breaks down.
Byers warned that all the life spans are rough estimates. A hurried burn or a change in manufacturing technique could cause premature failure.
He advised agencies to consider the longevity of their current storage media and always be developing migration strategies to a new one.
?These days, the rate of change in technology is so much faster,? Byers said. ?I?m convinced there will be a new storage technology within 10 years.?
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bellario
Suspended due to non-functional email address
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26. August 2006 @ 07:29 |
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It's been a while since I last updated this thread. Pushing this up.
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Senior Member
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26. August 2006 @ 11:45 |
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After reading all this I used to backup all my home movies about one time in two years I now will start backing up every year I hope they will make better disc just for this or is there any out there now?
RBROCK
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