Burned CDs Last 5 years Max -- Use Tape?

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."

If you say so...

Magnetic tape? Ok

Anyone know where I can download an MP3 jukebox for my Vic 20?

Re:If you say so...

Anyone know where I can download an MP3 jukebox for my Vic 20?

No, but there was a program listed in Zzap! 64 once that let you play audio tapes using your Commodore 64. Type in the program, press play on tape, turn your TV's volume up, and listen to something with slightly more signal than noise.

Conflicts with other studies

Haven't other studies confirmed much longer lifetimes in the past for CD-R? After all, we've had CD burners for longer than 2-5 years. Is this only a surprise because absolutely nobody has ever gone back and tried to read an old disc? Somehow I'm still doubtful of his conclusions.

Re:Conflicts with other studies

I've had burned CDs die very quickly as well though. Therefore the only solution is to upload your music onto P2P netwroks to save the back up copy fair use entitles you to.

Re:Conflicts with other studies

Yes, studies sponsored by the CD media consortium. Wonder who sponsored this latest study?

Umm, the tape backup consortium?

5 years max?

I have CDs that have lasted 10 years with no errors. Obviously 5 years is not the maximum life. Perhaps the maximum EXPECTED life.

Depends how you define lifetime

Keep in mind that CDs have a ton of error-correction coding on them. You could lose probably 20%-30% of the bits and still have a working CD. I suspect by "lifetime" the guy means when dye layer starts to deteriorate. Error correction can get you past that point, but you end up with a CD that reads fine one month, then "suddenly" develops dozens of bad sectors.

Most serious photographers I know re-burn their archives every one or two years.

Re:5 years max?

What does that mean? By 'maximum expected life' you surely mean the expected life of the medium, that is, the mean of the lifetimes of a good sample set of CDs. When a lifetime is quoted, e.g. for lightbulbs, the manufacturer doesn't guarantee that the product will fail when its expected lifetime expires!

CD-Rs with a 100 year warranty

We've known that CD-Rs will degrade for a long time. Hispace [hispace.com] have recently launched a new range of CD-Rs aimed at digital photographers. These disks use 24 caret gold to help add stability to the disks. As a result, they come with a 100 year warranty.

Your porn will be around for decades after all!!

Or my money back?

Great. I lose hundreds of precious photos. They give me a buck.

I can attest to that...

The wedding photographer for my wedding gave me a DVD of the video + photos. After about two years the DVDs were so degraded that I could not a single DVD player would recognize them. And that's with light usage... Now I keep important DVD as images on an external hard disk.

Re:I can attest to that...

I have had many problems with DVDs. I've had media that degrade quickly, and also writers that cause discs to degrade quickly. Every disc I wrote in late 2003 is bad. They started going bad after only a few months (in some cases, days).

I switched both burners and media and now have no problems. However, I still do a 100% verify, and don't totally trust DVD-R. For stuff I *really* want backed up, I put a PAR2 set on the disc, and I burn both DVD and at least one CD copy for offsite.

BTW I found that some really crappy DVD-ROM drives will read almost anything. All of those hundreds of bad discs that I have? I bought a shitty CompUSA DVD-ROM drive for $35, and it will read them all, even though NO other drive I own will read them (I tried Sony, 2 NEC, 1 Pioneer and 1 Lite-On DVD-R drives, plus Teac, Pioneer DVD-ROM drives). I have NO reasonable theory why this is, but the damn thing just reads anything. I'm glad of it too. I discovered this when I realized that my shitty $40 mintek set-top DVD player would play the discs and "better" players choked, so I decided to try a crappy DVD-ROM drive. So I can now make new copies of the messed-up discs.

Re:I can attest to that...

Usually the reason why crappy DVD-Video players play back things that don't play in other players isn't because the pickup is better, but because the decoder is more tolerant of non-standard discs. Some discs that play on PCs and these cheap players just won't play on the better ones because the disc itself is not made to the proper DVD spec. Most often I've seen either improperly encoded video or missing AUDIO_TS folders. Next to that is not having the files organized properly on the disc, or the wrong file system (ISO vs UDF)

Nothing lasts forever

When I first asked this question of how long CDs will last, I was told about 70 years.
I was also told that to lengthen a CDs shelf life, always store them vertically in a cool dry place, and clean them from the inside ring to the outer edge in a straight line.

I found an article from the Optical Storage Technology Association and they say it depends on the initial CD quality and handling.
According to this article, unrecorded CDRs last about 5-10 years, manufacturers claim recorded CDRs 50-200 years and recorded CDRWs 20-100 years.

More info: http://www.osta.org/technology/cdqa13.htm [osta.org]

Re:Nothing lasts forever

Also do not touch the coated side of the disc. Cleaning the read-side isn't generally going to degrade it in any way, even if it's scratched those can be buffed out of the clear plastic. The problem is the other side of the disc. The colored/laminated side is the material that gets written to. It's not protected with a thick plastic coating like a real pressed CD. Touching, mashing, or exposing that laminated side to pretty much anything out of the ordinary will shorten the life of the disc.

Some things that degrade CDs

• Using them as coasters
• DRM
• Leaving them on the dashboard of your car
• Contact with corrosives (orange juice, Bill O'Reilly, etc.)
• Using them as shuriken

after 5 years

I just recently tested ~120 cds from about 1999-2002.

Attempting to read them with a DVD drive failed many discs.

But reading with a CD drive I was able to read all of them (after some cleaning) except two (most files were readable) that were scratched.

It seem there is some difference between DVD and CD drives.

Most CDs were burned with 2-8x speed, I almost never use >16x today.

Instead of tape why not drives for long term?

Isn't the cost point close enough yet to just use hard drives instead for long term storage and not be too bad?

You can pick up OEM 250GB hard drives for around $100. Toss in a $50 USB case or a SATA case and you're looking at $1.67 a GB storage. Plus you're not limited to 4.5GB file size.

Sure drives fail but you won't be spinning them that often. I'm begining to think it may be worth it for the long term. Then use the USB drive or SATA as needed and if need be burn a disk.

Re:Museum Archives

Those are records. I don't know about you, but I don't have an LP-ROM drive.

Screw that - I'm going back to stone tablets

The article says to use magnetic tape because the CDs degrade.

So does tape. Unless you're the BOfH, in which case you have a tape safe. But you can't use that to store tapes - its not climate controlled, and you've got too many bodies hidden in it anyway ... but ever tried to read a 10-year-od tape on a new machine? I gave up - it was easier to connect to a serial port and just dump the whole database over the course of a week, its that bad. Then another day for updates. Todays USB and Firewire will be the next generation's serial ports.

So, use a hard drive?

Leave it sitting on a shelf too long and you get "stiction" - so that's no good either. And have you even TRIED to access a 10-year-old drive in todays machines? The bois tries to auto-config, and the machine won't boot.

Zip disks? Hahahah click of death hahahah (I've got several zip drives that are "unzipped")

Paper printouts? Well, those are good for a few decades, but not exactly portable ... anyone care to figure out how many acres of trees a hex dump of a 200-gig drive will take?

Nope, stone tablets - to hit anyone over the head with who thinks that there's any real long-term solution other than to just re-copy to the latest format and pray.

Re:Screw that - I'm going back to stone tablets

Gonna do some math here.

We'll assume that one can reliably retrieve data from a sheet of paper at 200 dpi.

At 200 Dpi, with reasonable page margins of 0.5" per side, you have 1500x2000 (2.86M) potential dots. Assume one bit per dot. That's approximately 0.36MB per page per side. Add one line of dots per side for alignment.

Since a page is evenly divisible by 5000 bytes, lets start there. 75 5000 byte blocks per page; each 5000 bytes will include:
64 bit address (8-bytes)
64 bit CRC (8-bytes)
Data (4984 bytes)

Additionally, since paper is (currently) a read-only media, we can preprocess the data using squashfs, thus assume that 4984 bytes is actually holding approximately 4k to 8k of data after compression and filesystem overhead.

(4k to 8k)*75==(300 to 600kB) per page, per side.

Thus, it would take roughly 175,000 pages, printed both sides, to equal a 200Gb hard drive. At 6ppm, which is pretty standard for a cheap laser printer, that would take 20 days to back up, not accounting for paper jams, toner or sleep.

Re:Screw that - I'm going back to stone tablets

Just to add some weight to the equation, 100,000 pages of paper (a pallet) weighs roughly a ton (all those years at Xerox were good for something;-). So your "back-up" would weigh in at right around 3,500 pounds, or the weight of a Run of the Mill Sedan (RMS). As we all know, RMS is also the abbreviation commonly used when prolestizing about Gnu. Gnu is an anagram for "Gun."

So, the moral of the story- it'll take a ton of work, but it's worth a shot.

Re:Photography's loss

1. depressingly high failure rate of hard disks

I find hard discs insanely more reliable than they used to be. I was building PCs in the 80's and I experienced the wonder of buying a full 20-count box of Seagate hard discs, and have EVERY DAMN ONE OF THEM FAIL IN 3 MONTHS.

I currently have 8 Maxtors and Hitachis of between 160 and 250 GB spinning in 3 machines at home. Most are > 2 years old. No problems. My older 40 and 80 GB machines have been given to friends to use in their older machines. They haven't had any failures either. I can't remember the last time I had a hard drive fail.

If your case is such that your hard drives are hot to the touch, don't blame the drive for failing. I think that's what causes most of the failures.

Re:Ziplock bags don't breathe,...

Another comment:

This is a quote from the story: "His recommendation: a hard-drive disk with 7,200 revolutions per minute." That's a way to have secure storage?

That's a recommendation? It's quite obvious that the author of the referenced story, John Blau, has no technical knowledge.

Another quote: "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."

I suppose that article was written by a public relations person and was published because someone was paid. Magnetic tapes are NOT reliable, in my experience.

Re:I guess it depends on how you treat them

Closer than the article, but still missing a crucial distinction. -R and -RW are very different. -R is pretty much as you say - the ink/dye/CHEMICAL layer that's written to is burned; this layer is not the reflective layer.

In -RW media, the write layer is a metallic layer that isn't "burned" but merely heated differentially to create regions of either more-crystalline or more-amorphous metal when cooled; these regions have different refractive characteristics, and can thus be distinguished by laser. This is why it's rewritable - the melting>glassy / melting>crystalline process is reversible.

http://www.usbyte.com/common/Re-writable_CD.htm [usbyte.com]

...contains a succinct but detailed explanation as good as any I've seen (many other sources confuse refractivity with reflectivity, and don't clearly explain that the write layer and the reflective layer in a -RW medium are indeed different layers).

So, to blather on only a little bit longer (too late?), to respond to the immediate contention in this subthread, the reflective layer is in NO case the very same layer as the data is written to. But, in practice, the top coating containing the reflective layer on any -R medium is so bloody thin as to make no difference. If it becomes separated from the surface of the disc, you're hosed. If you want to see how thin this layer is, stick a CD-R in a microwave for a few seconds, till it flashes, and observe the resulting flakes.

Back to the bigger question, the paragraph in this crappy article that says "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" is needlessliy confusing things by including "CD-RW" in the statement - to conflate a REVERSIBLE phase-change/metal layer-writing process with a PERMANENT burn/dye layer write process is stupid and confusing to anyone who doesn't know better. Whose fault it was to include that, I dunno.

This still leaves the question open as to whether the sorta-stable phase-change alloy ages in substantially the same or else a very different way than the permanently altered -R ink/dye layer, and whether any such difference affects the useful lifespan. I've NEVER seen this specific question rigorously answered. I'd love to hear from anyone who has links or direct info.