Up To 10% of CD-Rs Fail Within a Few Years 317
Whatever you think about the likelihood that a new kind of DVDs could last for 1,000 years, this note from reader crazyeyes should give you pause about expecting current CD-Rs to be reliably readable for decades. TechARP found a failure rate near 10% for CD-Rs recorded 7 to 9 years ago, after storage in ideal conditions. On some, one or more individual files could not be recovered; others were not reliably readable on two separate drives. "In the past, hard disk drives were small (in capacity) and costly. To make up for the lack of affordable storage, many turned to CD-Rs. As it became common to store backups and personal pictures, videos, etc. on CD-Rs, the lifespan of these discs became a concern. According to manufacturers, CD-Rs should last for decades. Some even quoted an upper limit of 120 years based on accelerated aging tests! That sure is a long time, isn't it? But will CD-Rs really last that long?"
According to... (Score:5, Insightful)
According to manufacturers, CD-Rs should last for decades.
According to their marketing dept., rather.
Re:According to... (Score:5, Funny)
Well you of course have to use an error correcting code. people who don't do that then blame the manufacturer's got what they deserved. For example, personally I get 120 years out of my CDs by encoding 699Megabytes of errorcorretion. this leaves me with 1 byte of data. but it last 120 years.
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What are you talking about? AFAICT (quick google and wikiread) the only type of error correction you get on CD-Rs is inherent in the format of the disk, so it doesn't cost you any storage space (for data anyway). If you start adding extra layers of ECC (e.g duplicate all files and keep a hash table)then your not dealing with anything CD specific anyway.
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Re:According to... (Score:4, Insightful)
So you run 1000+ CD & DVDs through a "checker" once a year just to see if they're still working? Or do you just not have a lot of stuff to back up? :)
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50,000 year retention time (Score:5, Funny)
Re:According to... (Score:5, Informative)
Re:According to... (Score:5, Insightful)
I would suggest as the cost per unit fell through the floor, so did any regard for quality control as well as the consumers lack of motiviation to drive all the way back to the store and get a replacement.
re: recording speeds also probably matter (Score:5, Interesting)
Back in the earlier days of CDR, a "high speed recorder" was recording at a whopping 4x or so. As drive recording speeds increased, the CDRs rated for those higher speeds had to become more responsive to the laser hitting it for a shorter period of time. How do you accomplish that? One big way was spreading the dye out in a thinner layer. That's likely to have a negative effect on longevity.
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Re:According to... (Score:4, Informative)
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I had a strange experience the other week like this. I went back to some old CD-Rs, which would have ranged from about 7-10 years in age. Some were among the very first CDs I ever burned, on my old 2x drive, back in the days when the disks themselves cost £1.50 a pop here in the UK. The very oldest were actually fine. The slightly more recent ones (at the 7 year end of the range) were far more of a mixed bag. Around 1/3rd of them could be read only partially, or not at all. I'm pretty sure that the lo
Re:According to... (Score:5, Interesting)
About 4 years later we lost a drive array and wanted to restore from the CD backup. I set one of my people to offloading the CDs to a new set of drives. Meanwhile I went to our offsite backup and copied the relevant data back to the server in a few hours. Days later my employee comes back to me and says that "most" of the CDs are coasters and the data is gone. It turns out that about 1/3rd of the CDrs either didn't burn properly in the first place, or had failed in the 2-6 years they were on a shelf.
The lesson was a simple one. The offsite backup server was faster, easier and more reliable than the CDRs. Of course, management blamed the (long since) fired employee that burned most of them. They also paid 5k$ for a brand new Mass burner / labeler, and used up nearly a week of production time getting it working and tested.
A year later the clients all moved to USB thumb drives and or FTP transfer for the data, making the fancy mass burner obsolete.
Re:According to... (Score:5, Informative)
If you have not tested your backup system, you do not have a backup system.
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Two observations:
1) You've been lucky. Others have not faired as well (and some of those others have tried very hard to only buy quality media)
2) CDs and even DVDs are too small.
Who wants to copy 222 DVDs to fill up just one terabyte drive? Who's got the time to sit there shuffling disks? I store backups on external hard disks. They cost roughly double what you'd spend on quality media and while it takes hours to copy across a terabyte of data you don't have to babysit it.
Video only still belongs on DVD bec
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The thing is, it's a lot easier (and probably cheaper) to buy two 1.5TB SATA drives and just back up from one to the other every now and then, instead of burning 1500/4.7 discs once a month. I've moved to a completely hard-drive based backup solution, where I have every piece of important data on two separate hard drives. (Incremental) backups take 5 minutes instead of half a month, and all I need to store is two 3.5" hard drives... far better than hundreds of optical discs...
As for optical media failures:
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isn't that part of the problem with optical media? Every trip from storage to the reader is an opportunity for damage to occur. At least a hard drive's disk is kept safely in a metal box away from humans.
Sure, that is a problem but processes can be put in place to keep the risk of damage low, it isn't very difficult to handle optical media correctly and carefully. One solution would be to just use DVD-RAM discs which can be bought in protective catridges which prevent the disc surface from being touched an
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CD rot is the result of bacteria getting inside the disc to eat the silver oxide or glue. And that's a result of the edge of the disc being damaged such that they can crawl inside. As long as the edge is remains undamaged/saled you'll be okay. Ditto if you keep your CDs in a dry place (i.e. not your wet basement) because bacteria don't like dry zones.
VHS tapes have a similar problem where exposure to humdity makes the magnetic media literally fall off. So you need to keep them someplace dry.
Re:According to... (Score:4, Informative)
It's not that simple. A number of brands are rebranded other brands. Taiyo Yuden is usually considered the best of the best.
For example, HP discs used to be Taiyo Yuden. But they have switched to something else now.
Depends on the brand (Score:5, Interesting)
I've experienced this myself lately with a bunch of disks that were now useless. It was cheaper off brand disks that failed. The irony is at the time I got them, they were the ONLY disks I could get to work on my CD player.
So far I've had no failure with CD-R's from Sony, TDK etc... Which were the disks my CD player simply would NOT play.
Re:Depends on the brand (Score:5, Informative)
By brand, you mean "manufacturer". Most big names, such as Sony, etc., don't make their own disks, but buy them from an external factory and place their own labels on them. The various manufacturers have different chemicals and dyes embedded in their discs, and its that chemical composition that determines the longevity.
Usually the brand will buy discs exclusively from one factory, but some of the off-brands (such as house-branded Office Depot or no-name discs at Micro Center) could be sourced from anywhere, and their quality will vary widely.
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Re:Depends on the brand (Score:4, Interesting)
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I have CD-R's from a variety of brands that have failed in the first few years. The discs from my burner back in '99 are dead, I tried those a year or so ago into the trash they went. Personally I'm not sure if it's a problem with the discs in some cases, or the newer drives not following the proper standards. I also have DVD-R's that no longer read, and DVD-RW's
In some cases, I find that the new multi-drives will fail to properly read burned CDRs(much like the days of yesteryear when burning was hitting
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Yes, older Plextor drives are great for reading discs that other readers have problems with. I work at a company specializing in forensic software for optical media and we recommend the older Plextors to our customers and we always have a stockpile at our office. The older Plextor drives were built with much better optics and other components compared to the cheap stuff drives are made of today which is a major reason they read discs better. However, current Plextor drives are all rebadged drives from ot
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I recommend to always update your BIOS. From what I know, this gives the BIOS infos on how to read more recent discs (they are apparently not all equal, which makes sense).
I have to see it help though. Some readers are just shit. (Like my Samsung for DVD-RAMs [firmware crashes. hard.])
i have entire 1993 CD-R spindle (Score:5, Interesting)
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I'm a little confused on the year. Does the collection start at '93 or '95?
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There's error correction on CDs, the problem is that a 'bad' burner could produce a disk which is correctable to the proper data, but later on as some material degrades, will become unreadable, as opposed to simply requiring some error correction.
There used to be some brands that the firmware would show stats of that, however there haven't for a number of years, barring a few firmware hacks. (Amusing having to hack the firmware to get information that used to be semi-common.)
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What a bad burner does? Burn a bad bit?
The problem is that things in the physical world are rarely binary. Sure, an "on" might be the laser bounces back and an "off" is where the laser passes through. But what's the quality of the holes made and what to their boundaries look like. I'm guessing that the light reflected back is never 100% and the light that goes through is never 0%, but rather there are fuzzy boundaries. If the laser that does the burning doesn't do a good job on the boundaries between 1'
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Re:i have entire 1993 CD-R spindle (Score:5, Informative)
The earlier burners were expensive and better quality so it's probably more of a burner issue than a disk issue in this case.
Not likely, burners do not affect the aging of disks. It is the dye on the Aluminum that ages and eventually kills the disk - typically a result of oxidization. Cheaper disks use cheaper dyes. The brand name disks are more expensive because they use dyes that are patented - and therefor more expensive to license. The plastic coating that protects the dye from oxidization is also likely to be different on the more expensive disks.
Personally, I've only noticed flaws in the cheap disks - the brand name disks appear to age well. But the cheap disks are still very useful. I use then when distributing files to friends and family - this way I do not have to worry about getting them back.
Re:i have entire 1993 CD-R spindle (Score:5, Interesting)
The 10% failure rate reported was from 1 person's experience copying old discs back to a hard drive. No mention was made of the CD hardware used or at what speed they were recorded at.
Follow the Orange Book (Score:4, Insightful)
120yers, lets start with archive rated CD-R, and use a decent recorder with a tray. Then write according to the orange book specifications.
Were those disks verified? (Score:5, Interesting)
I've had CD-Rs and DVD-Rs that I burned over a decade ago still read fine. However, those disks were verified burns where I immmediately read back the data with Nero to make sure they were ok.
There was a time when I didn't do verified burns. Those disks have a ridiculously high failure rate, but I'm betting they were bad burns in the first place. With most media I get close to a 10% failure rate on verifying the burns.
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4-16x for CDs (would like a lower speed, but the drive does not support it) and 2-4x for DVDs depending on how many DVDs I am recording at once. If I need to record just one CD/DVD, I will record it at the lower speed, if my friend asked me to record a lot of DVD, I will use the faster speed.
I think I should buy an old CDRW drive that can record CDs at 1-2x, they would probably last longer. Or I can record that music to a cassette.
Not sure that hard drives are any better... (Score:5, Insightful)
In the past, hard disk drives were small (in capacity) and costly. To make up for the lack of affordable storage, many turned to CD-Rs.
Though I'm not convinced many consumer hard drives have shelf lives on the same order as the optical media that some of us are backing up to. Add to that the fact that hard drive interfaces do change fairly often (some of us still have systems in the transitional period between IDE and SATA), and you could have potentially more irritating problems if you were to back up to hard drives instead.
I suspect for paranoid user it may be more cost effective to backup multiple times to CD-R rather than to a hard drive. And on top of that, if one CD of your backup set goes, you are only out 700 MB or so. If you have a series of backups on a single 100+ GB hard drive, and it fails, you may be out everything that was on that drive.
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Though I'm not convinced many consumer hard drives have shelf lives on the same order as the optical media that some of us are backing up to.
Actually, kept in a cool dry place most hard drives will last pretty well. They only have durable SMT components on them these days. The only thing you've really got to worry too much about (Assuming you keep them away from moisture) is the bearing lube*. I suggest buying drives from different manufacturers if you're worried about that.
* I don't know if this has ever actually happened to a hard disk, but the lubricant used on the headlight switch of my 300ZX was corrosive after the passage of years, leading
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Fortunately, Nissan doesn't make hard drives(*).
Of course, the grease in the bearings can dry out, but that really doesn't seem to be much of a problem: It's a silicone-based substance, and it's wrapped up pretty tightly away from the ambient environment. There just isn't much for it to do except sit around and be stable... Old drives used oilite (sintered bronze) ball bearings almost as a rule, while newer ones often use fluid dynamic bearings -- and in either case, that aspect is fairly stable.
I've rec
Re:Not sure that hard drives are any better... (Score:4, Informative)
"Fairly often"? On what timescale?
In the consumer market: We had ATA for something like twenty years. And now we have SATA, with no replacement in sight.
Before that, we (consumers) had MFM and RLL.
And that, sir, is the complete history of PC hard drive interfaces.
So, again: "Fairly often"?
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In the consumer market: We had ATA for something like twenty years. And now we have SATA, with no replacement in sight.
Before that, we (consumers) had MFM and RLL.
Unless, of course, you were a Mac user. In which case you used SCSI for some time, before switching to IDE.
And now most people are using SATA.
Assuming, of course, that they are using a system that is only a few years old (or less). There are still plenty of systems in operation using IDE, as much as the drive manufacturers might not want to believe it.
And of course, if you are backing up your files, then the duration for which you want to keep those files may vary. If someone wants to keep those ol
Re:Not sure that hard drives are any better... (Score:5, Insightful)
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I don't see USB going out anytime soon
It wasn't that long ago we thought the same about the parallel port. I suspect I'm not the only person here who used a Zip drive through a parallel port interface "back in the day".
does anyone really connect their printer via parallel port anymore?
Well, junior, we used to connect more than just that through parallel. And not everyone likes to replace printers that still work; I have a parallel port laserjet that I still use from time to time because it is the cheapest way to print available to me at home.
"Archiving" a single medium isn't necessary (Score:4, Interesting)
HD storage is incredibly cheap and like others have pointed out, we've only had 3 major interface changes in the past 20 years.
I can't read anything from my first personal 10 MB HD, either, but that never mattered. Each upgrade, transferring that to a new set of drives was trivial. I still have emails I wrote 10 years ago, not because I can read the drives. Those drives have little to no utility to me as a storage medium. I have that data because it was a 250MB HD and that takes up less space on my NAS than a single 1080p movie trailer.
In five year's time, I'm not going to be interested in reading the HDs I have now because they'll have long been transferred to the 50TB NAS type solution I'll have then.
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In five year's time, I'm not going to be interested in reading the HDs I have now because they'll have long been transferred to the 50TB NAS type solution I'll have then.
And what if your NAS fails? Or is it fully redundant RAID-1? Or are you backing up to something else?
Hard drives have advantages over optical media (Score:3, Interesting)
Backups are not archives. Backups are a copy of working state, such that you can restore working state if it is lost or corrupted, partially or totally.
Optical media is poorly suited to backups, for a number of reasons. Optical media backups are:
Old news (Score:4, Informative)
And water is wet (Score:2, Interesting)
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dvdisaster anyone? (Score:5, Informative)
dvdisaster [dvdisaster.net] is what I use now...both on CDs and DVDs (it also supports dual-layer)
think of it as a way to embed par2 (parity) onto a disc (it requires an ISO image that you create in your favorite authoring software, then after it's done embedding the parity in it, you can burn it)
alternately, you can create a separate recovery data which you can store on backup tapes or hard drives or on another disc, etc.
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think of it as a way to embed par2 (parity) onto a disc
I'm not trying to be smart, but why not just burn disks full of par2 files? I'm asking because that is exactly what I currently do. It has the added advantage of letting you span disks with data that is larger than the size of one disk. Just make a disk image of whatever size, and then act like you're going to post it on usenet except burn to disk instead.
Not surprising (Score:2)
After all it seems the only reliable storage is flash memory, preferably SLC
Buy Quality Blanks!!! (Score:5, Insightful)
"Studies" like this are useless if they don't include information from the codes off the CD's (not the label on the box!) as to who the manufacturer is.
Get the Taiyo Yuden and MAM-A Gold blanks and you won't have issues like this.
Also please read the Wikipedia article on CD-ROMs, and expecially the references. You WILL end up with better burns if you do.
Re:Buy Quality Blanks!!! (Score:4, Informative)
Mam-a is not what it used to be.
Buy Taiyo Yuden or Falcon.
Re:Buy Quality Blanks!!! (Score:5, Interesting)
The "codes" on a CD-R that indicate the manufactuer are pretty much meaningless. Why? Because they are often the code assigned to the manufacturer of the stamper.
Stampers are hard to make and require a cleanroom, lots of chemicals and skilled people. After you have a stamper, you put it into a machine and any idiot can turn out CD-Rs. So plenty of manufacturers with the cleanroom facilities and the knowledgeable staff sell stampers. So you have some place like Ritek that will sell anyone stampers. Now Wong's Cheaper Discs buys up some stampers from Ritek and starts turning out discs.
Since Wong's Cheaper Discs are a few cents less than anyone else's that week, Memorex and lots of other folks buy up discs from Wong's. Sadly for Ritek, all the discs from Wong's have the manufacturer code from Ritek. Now someone from Ritek might be able to tell you that these discs were not actually made by Ritek, but it is going to take someone familiar with their processes to tell you that. It is not obvious.
So the manufacturer codes on discs are pretty useless. About the only thing you can do is buy discs from reputable manufacturers where you actually know who the manufacturer is.
Re:Buy Quality Blanks!!! (Score:4, Interesting)
I want to disagree with you, cdrguru, but with your low UID and telling username, I find myself unable to.
Instead, I'd like to ask you a question:
I had understood that, for the past many years, most CDs (whether recordable or not) were injection-molded, not stamped. Do you have any evidence or anecdotes to suggest that the primary manufacturing process for recordable media these days still involves stamping?
Re:Buy Quality Blanks!!! (Score:4, Interesting)
Yes there is not a 1:1 correspondence between the code and the actual manufacturer.
BUT for people who follow the industry the codes can still be used to identify the real manufacturer, and in many cases can be used to identify people who are forging manufacturer IDs. Lots of people like to put TY02 on discs that never saw any part of Japan.
And in any case they are FAR more meaningful than the label on the box.
My experiences with CD-Rs - some good, some not (Score:5, Interesting)
For the disks that I could not get 100% reads on from the Toshiba drive, I tried them in several other computers using a variety of programs. Mostly I was not able to get results as good as EAC on the Toshiba drive. I tried two Mac Mini's using Max and an old Mac G3 using cdparanoia from the command line, and got lots of failures. Then I tried Max on my MacBook and they all read perfectly. Go figure.
I theorize that one reason the disks had errors was that they were labeled using a Sharpie. According to the NIST report on CD-R failures (nvl.nist.gov/pub/nistpubs/jres/109/5/j95sla.pdf), this is a really, really bad idea. Since I read that report, I've been adamant about using only water-based markers on CDs and DVDs.
Re:My experiences with CD-Rs - some good, some not (Score:4, Informative)
Storage under "ideal conditions"... (Score:2)
And, while I'm asking questions, has anyone ever experimented with submerging disks in (water | mineral oil | etc) to see if that would reduce long-term degradation? If we're talking 5 years or more I wouldn't mind drying/cleaning them to get my data.
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cool dry place w/ no sunlight / UV. get a large CD storage folder (they usually have em for holding 500 or so disks and leave it in a drawer.
see here : http://www.supermediastore.com/cd-dvd-wallet-wallets-cd-holders-cd-storages-organizer-epv-520.html
520 Disc Capacity CD DVD Wallet Case offers Koskin/Black Leather-Like Quality CD/DVD Portfolio, Organizer, Case, Wallet, Holder with Sturdy Handle, Comfort Shoulder Strap, Removable/Refillable Binder Style Inserts with Easy On/Off Switch. Perfect for professiona
CD-Rs Design is Flawed. DVD-R More Reliable. (Score:5, Interesting)
CD-Rs design is very flawed in that the recording layer is near the surface as opposed to being well protected in the middle, as it is in DVD-Rs.
I've had numerous CD-Rs that were well cared for get flaky after a year or so; data is usually still there, but requires use of various recovery tools.
DVD-Rs have been very reliable in comparison - never had a problem.
With that said, what I do for archival data is use two different brands of DVD-R *plus*, when possible, save two, sometimes even three, duplicate copies of the data on the same DVD-R. That way I have two to as many as six copies of the data, often including dups on the same DVD-R allowing for faster, more convenient recovery.
Ron
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As long as we're presenting anecdotal evidence....
A decade or so ago, I used to burn my disks on a Plextor PX-820. Every single disk that I've tried, no matter what the manufacture, has read just fine on modern systems.
Please allow me to suggest that your currently-unreadable burns were bad to begin with. Please further allow me to suggest that a bad burner back in the day is still a bad burner today, and that any media you have from Way Back When is sure to reflect this fact.
the best archival medium I've used thus far (Score:3, Funny)
...is the venerable 5.25" floppy disk, circa pre-1985. My Apple // disks from that time are still readable. It takes rather a long time to back up my 1TB WD "Green" HD onto the Apple //GS I have networked to my main machine, but hey, backups are important! :)
Punched cards or punched tape (Score:3, Funny)
Punched cards or punched tape using something stronger than ordinary paper is very good for long-term storage. In ideal conditions it can last millennia.
If that's not good enough, non-organic inks on cave walls and cut indentations in stone can last even longer if protected.
OT: "It's been 4 minutes since you last successfully posted a comment" WTF? When did /. start limiting you to 1 comment every 4 minutes?
how to get good burn quality (Score:5, Informative)
I burn thousands of CDs and DVDs per week and here are some tips
- use pro grade media from Taiyo Yuden (Made in Japan) or Falcon (Made in UAE). Verbatim still makes some good media but you have to know what to look for (Datalife Plus) because they also buy cheap media and rebrand it.
- burn cd-r at 16 or 24x. 32x is ok for short-term use. Even the best discs will fail if you burn at maximum speed.
- burn dvd-r at 8x
- if you must burn dvd-r at 16x, test your quality regularly for signs of failure.
how to test the quality:
- Plextor made good drives bundled with Plextools testing software but they are no longer making their own drives. For a replacement to Plextools, see Opti Drive Control at cdspeed2000.com
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Yep, slower burn speed can make a difference. One of those details few people are aware of.
For DVD-Rs, I limit burning to 4X. Probably overly conservative; 8X, as you suggest, is likely fine too.
Ron
Note the "idal conditions"... (Score:2)
I have had CD-Rs fail within weeks after perfect verifies. You should expect a lot less than the given times in "normal conditions".
4 CD, Raid 5. (Score:5, Informative)
I used-to make 2 CDs of every ISO, until I figured out how best to utilize PAR2.
PAR2 calculates parity information on a set of files, and writes out a file which can be used in the event that any of the files is damaged. This is quite similar to RAID-5, but PAR2 is more robust, and works on any files, not just equally sized hard drives.
Though it's no help on DVDs, CDs work GREAT with PAR2, because of their two different methods of recording. Mode 1, as all regular files are stored, reduces the amount of space available by about 12.5%, using that space for additional error correction data. Audio CDs, and Video CDs, where a single bit error isn't nearly as critical, are recorded in Mode 2, with substantially reduced error correction, but about 100MBs more usable space available.
PAR2 is similarly resilient to errors, so it can safely be used with Mode 2. This allows much more space for the parity information, and the opportunity to be safe against, and correct, respectively more damage to a disk.
Specifically, I recomend a 4-disk parity set. You fill 3 CDs full of data, and tell PAR2 to calculate 37% recovery data on those files. The first 33.334% allows you to RECOVER THE DATA FROM ONE COMPLETELY LOST CD, no matter which of the 3 it is. That still leaves you with a margin of 3.667%, so those two CDs you DO have, can have a few bad sectors as well, and all the data from the lost CD, as well as undamaged versions of the files on the two lightly damaged CDs can be recovered. Alternatively, if you DON'T lose an entire CD, all three (4 actually) CDs can have numerous bad sectors, in any distribution, up to a total of 37% of all the discs, and pristine data can still be recovered.
The method to do all this is quite simple. Just run the par2create command, telling it to create 37% recovery information. Then take the resulting BASENAME.Par2+??????? file, and create a CUE file, describing a CD with a single track across the whole CD, with the PAR2 file as the supposed audio data. eg.:
Now, any CD recording software that understands CUE files will happily record this to disc. On Unix systems, you can choose cdrecord, or cdrdao.
Now, like regular audio CDs and Video CDs, you can't just use or copy this data off the disc like a normal file on a CD. There are programs for converting VCDs into regular files, something like dat2mpeg, but I prefer a more generalized tool that can do the job:
mplayer vcd://2 -dumpstream -dumpfile par2.bin
You'll note that checksums of the file and the data on disk don't quite match... This is because, in mode2, data MUST be padded to the block size. PAR2 files are fine with it, and the padding is silently discarded.
Something like DD_RESCUE to copy the (normal) files off the other CDs, in the event of damage, is probably necessary as well. Then, once you've got 3CDs worth of data (eg. 700MB CDs x 3 = 2100MBytes) you can run par2recover and all with be repaired, like magic.
The only footnote being that calculating the parity information isn't fast, so this method is probably slower than just recording 2 copies of every CD. Also, if you lose more than 37% of the data across all the discs, the error-free originals can't be recovered. However, I consider it more reliable than duplicate discs, if only because the odds of an error on the same sector of two discs (or one disc lost, and the backup with a few errors), seems more likely than 37% of the discs being damaged beyond hope. And as an added bonus, you save 1/3rd on your CD-R purchases.
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Erm, that isn't Mode 2 records, that's audio data padded to 2352 byte blocks.
Mode 2 sectors have a sync header plus a (minutes/seconds/sector No/Mode No) for each block and have 2336 bytes for each block. White book (video CD) sectors have an additional XA header and a 4 byte checksum with a final data rate of 2324 bytes per sector (Mode 2/Form 2 sectors).
I had a different problem (Score:3, Interesting)
I go and reinstall windows on my dad's machine. I use an nLited burnt CD I made(HP made CD) and it won't even boot. Tried a linux recovery CD(same maker of CD), would not boot. Somehow, out of the 6 tries I was able to get the XP install CD to boot. It did. Failed about halfway, asking for the file "ASMS", which didn't exist(but a folder did).
So, bad Cd? I fire up a virtual machine, and install XP in the machine and it works flawlessly.
I go back to my dad's machine & eventually try my legit store-bought XP install CD, and it continued to install. I burn a CD of my dad's backed up data(again, an HP cd), and it reads just fine on my machine I burned it from, won't read at all on my dad's system.
Wow, I'm lucky.
Physical damage trumps all other considerations (Score:3, Interesting)
But no one really made it clear how physically fragile the damn things were, especially in comparison to pressed silver CDs. I kept my backups in a booklet-style binder. Yes, I know that's considered less than ideal, but these discs weren't burned solely for archival purposes -- I needed to be able to page through them efficiently. Most of them were taken out and used every so often -- say, four times a year on average, sometimes more -- and never knowingly abused.
Over time, the foil on quite a few of them started to flake off. Unbranded Taiyo Yudens, which are so often acclaimed, seem to be the most vulnerable -- I've had quite a few that developed holes in the foil, especially near the edge. It's a shame, because the discs read beautifully otherwise, and seem to ace most media tests. But the foil seems all too easy to damage.
(I've also lost a handful of Mitsui Silvers that way, whereas Mitsui Golds seem to have a more robust armoring on top, as do some of the 2nd tier discs I've tried -- Sony, Maxell, TDK, Memorex. Meanwhile, I've seen no evident physical damage to my DVD-Rs so far; fingers crossed.)
Use CD-RWs instead. (Score:3, Interesting)
So the quality got better! (Score:4, Informative)
(Throw a coin. If it's heads, read the P.S. first. Lucky you.)
I remember a large-scale test with pretty much all CD-Rs and CD-RWs on the market back in (around) 2000 (I think).
They used a climate chamber with all the effects of nature, amplified so much, that they could simulate 10 years of normal daylight, humidity, etc.
The blue and green materials died first. (I think blue was much worse than green, but only for some models.) After an average of 3-4 years! The original golden material survived better, but not much.
Only CD-RWs could even come close to 20 years, because they had to be manufactured better, and use other materials.
I also remember that our very first CD-Rs, burned on a huge rented SCSI burner, at 13 DM a piece, were unreadable right when we took them out of the archive one year later. Which was still better than those 50% who never survived the first burning at all.
Everyone around me always tells me that his old CD-Rs still work, and things like that. And they do not take me seriously when I tell them of the low life-span.
But usually, they do not even take them out to try them. And if they do, they look at the directory index, and think that means that all data is OK. And even than sometimes fails.
Also, they rarely can find CD-Rs, old enough to prove me right on the spot.
But if you take those discs, transfer everything and all its data to the hard disk, and then look at what you get, usually what you're left with, looks like a shattered mirror or the output of a random number generator.
P.S.: Sorry, just watched the Watchmen again (is that a pun?), and inadvertently wrote the whole comment in Rohrschach's journal voice.
Archival hard drives? (Score:3, Interesting)
I've often wondered if there'd be a market for hard drives especially designed for long-term archiving.
They'd be slow-spinning, with slow transfer rates, and hold less data per square centimeter of disk surface, for the extra magnetic integrity. Some archivists wouldn't mind if they were very large, too, or even very heavy. They could be shelved in a "slow cloud" backup warehouse. They'd be "set and forget" - used once to record the data, then shelved and hopefully never used again, and only when a slow data restoration would be no hardship.
Surely there's a niche market for an odd device with specs that emphasize duration of storage, rather than the usual "faster, smaller" attributes. Until those long-awaited chalcedony drives arrive, it seems there's a niche opportunity here for a low-volume, high-margin manufacturer.
Buy Quality Media (Score:4, Interesting)
is what it takes to get the maximum lifespan from your archives. This means not buying the cheapest shit you can for your important data. Instead the only one who meets the entire specification is Verbatim media. Sure it's not the cheapest when it comes to media but in the long run, it's certainly cheaper then buying whatever happens to be on sale at best buy and if your data is important, then spend the extra money for quality media, which is exactly what Verbatim is.
In my normal useage, I now only buy Verbatim for anything that I need to ensure is archived for any length of time. Otherwise for a quick and dirty backup, I'm now using an external drive then burned to Verbatim media for longterm storage. For those cheap and rapidly changing ISO images, the cheap disks are sufficient (things like FC/Ubunta/Kubunta and other Linux Distro's) In fact, I've found that buying Verbatim Rewritable media has become the cheapest solution for the many test images I burn due to the quality of the material. I'm still operating on my first batch of 10 Verbatim DVD/RW disks (now pushing 5 yrs) because they've lasted through so many rewrite cycles. I've also used cheap disks and the damn things have gone to crap in just a few months.
100% failure sounds right for Verbatim (Score:4, Interesting)
Long time storage is a problem (Score:3, Interesting)
That CDs/DVDs won't last forever was a given. That we relied on them is simply due to us considering the promised 10 years "long". Other media last longer. But is there something that will last forever?
Let's be honest here. Imagine our civilisation fails for some reason. And in a millenium or two, archeologists want to find out how we lived. What will they find? Well, of course they will find a lot of plastic bags and maybe a few cans, a couple glass bottles and some foundations of houses and churches. But anything we wrote? Any data we collected? Art? Anything at all that shows we were literate?
Aside of grave stones?
It's amazing that in almost 10 millenia of culture we didn't manage to invent anything but stone tablets to record information "forever". Nothing else will survive. Digital data fails before a century. Current paper won't survive for more than a few centuries, even if stored properly.
It's a curious mind experiment to ponder what would the average archeologist think of us if he finds some of our artifacts with no further data. Considering how most artefacts that make no immediate sense are classified as "religious" or "cultural", my guess is that we'll be considered a lot more religious than we really are, and that Pepsi is our god, and the Pepsi cultists were in heated battle with those that worship the Mountain Dew.
Where are the quality disks gone to ??? (Score:4, Interesting)
As DJ I used to store all my vinyl on CD as backup. I've once used my cd's for over a year in hard-dj-labor and most of them did survive although I might add:
From personal experience... (Score:3, Informative)
Everything I was trying to open recently was about 7 years old, and about half the discs wouldn't even read, or would throw errors when I tried to actually copy anything off them.
It also opened up the issue of file formats...what the hell am I going to do with an Aldus Pagemaker file from 2001? Nothing in Adobe CS3 had any idea what to do with it. I think that's what that extension was, anyway. Archiving photos and videos is pretty safe as far as file formats go. A BMP is crappy and gigantic next to a TIFF or PNG, but you can still open it.
Proprietary layout formats though...they get old faster than cheese in a hot car.
Re: (Score:2)
In many cases, yes. Why wouldn't I want to see the photos from today in thirty years?
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I do agree that archiving all digital photos is silly, the delete key exists for a reason.
I'm guilty of this. Thing is, I'm not being anal... actually the opposite - I'm lazy and hard drives are cheap. It would take days to go through all of my old pictures... or I can just wait for my current drive to die and buy the latest quadrillion-teramegabyte drive that's on the market at the time.
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Did you mean "will you be able to look at the JEPGs, TIFFs, or whatever formats you use now?" -- that question would have been more reasonable, although I don't believe they'll go away any time soon, especially with publicly documented specifications on them. Hell, look in ImageMagick (or to a lesser extent, GIMP), it contains support for several formats long obsolete since the 1980s, but support is maintained within them.
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If the photos are in that format, yes. In the worst case I can use an x86 emulator for whatever architecture we use at that time, run windows and view my JPGs.
Given the popularity of x86, I'm sure there will be plenty of emulators.
Re:doubtful (Score:5, Funny)
I would say take the Rosetta Stone approach.
Good advice. I save three word 97 copies of all my documents. One in English, one in classical Greek, and one in in hieroglyphics.
Re:doubtful (Score:5, Funny)
I save mine in Arial, Times New Roman and Wingdings.
Is this sufficient?
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No, you need a copy in Comic Sans as well so that the people who try to decode it in the future have a wide corpus of works with which to compare it.
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Just look at top of the line storage 30 years ago.
Chances are that if you haven't looked at it in 30 years, it wasn't all that important.
I mean, would the ability to read my Apple ][e disks be nostalgic? Yeah. Nostalgic enough that I've felt the need to track down a machine to read them since I got rid of it in the early 90s? No. Everything that was important enough got transferred over when I got a new machine.
Re:doubtful (Score:5, Funny)
30 years ago I punched my programs on "archival quality" punch cards. They weren't like regular cardboard cards, they had a higher rag content that would assure they'd retain their shape longer with less chance of bending.
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I used to think the same thing. Then I started doing an inventory of my data. Scrapping the ISOs, movies, music (which for me actually will fit on one DVD), games, and all the rest, I need two DVDs to do a backup of the data that I have a real need to keep: e-mail, personal documents, and photos that I've taken, plus a few extra files like encryption keys. It totals up to about 7GB -- easily backed up on a regular basis. Once Windows 7 hits RTM and I can get a final installation of it in place off of Te
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magnetic material can be digitally refreshed without consuming additional resources
CD/DVD-RW? I have used both. DVD-RAM isn't as popular, but is used essentially exactly like magnetic media.