Guide to Digital Preservation from NIST

Little Hamster writes "The scientists working on the Digital Preservation Program at the National Institute of Standards and Technology (NIST) has released an excellent 50 page guide on care and handling of CDs and DVDs for long term storage. It talks about the effects of light, moisture, radiation, scratches, marking, adhesive labels, and even playback on the discs. For those slashdotters who is not familiar with the physical made up of these optical discs, there is a very nice chapter explaining all the background. And if you only want to know how to care for your precious data, there is a one page summary. And yes, they agreed that glued-on labels are harmful."

Comments

Post it notes?

[SlideGuitar]

I wonder if post it notes are bad?

Felt markers for labeling CDs

[sidney]

Use a black felt pen. If you do it right you get to label the CD and defeat copy protection at the same time

Re:Felt markers for labeling CDs

[fm6]

I read somewhere that felt markers with water-based inks were safer than those that used other solvents. Question is, how to tell what kind of ink is in your market?

Re:Felt markers for labeling CDs

[operagost]

That's a good question. Is a Sharpie safe? They're about the only commonly found markers that seem to work. Frankly, anything water-based is worthless- they wipe off.

The recommendation to stay away from any marker that uses solvents is somewhat silly for the reason you hinted at - water is also a solvent.

Re:Felt markers for labeling CDs

[pod]

Unless it says otherwise, assume it's solvent-based. Or you can just smell it.

Oh come on...

[devnullish]

Or come off it! Yes, osme of the tips are interesting, but if some idiot (who reads Slashdot and/or would visit a web site regarding something like this) actually needs to be told glued on labels are bad - well I guess idiots are like rabbits, they like to profusely populate ;) I'm not criticizing the article (nor am I trolling), I just truly wonder why someone would need to be told some of the things mentioned. I guess common sense is like a geek, it does profusely populate.

Re:Oh come on...

[Anonymous Coward]

Not everyone can be as smart and as gifted as you.

I dont trust any format.

[MrRTFM]

I've had floppies, CDs, DATs, Zip disks and even tapes go corrupt over time.

If it wasnt for multiple backups I'd have been stuffed, so for my personal stuff (and work) I keep everything on the hard disk. Luckily the size doubles every few years, so as long as the size of the data doesnt outgrow the size of the drives, I'll be fine.

It wouldn't hurt to get all your old disks and tapes and (un?) back them up onto a spare hard drive before its too late.

Re:I dont trust any format.

[devnullish]

Well, I'd argue that. Punch cards don't corrupt althoguh I found MANY ways to screw them up (and some were creative too! Try target practive with a paperclip bow and arrow trying to get the arrow through the punch holes ;))

Re:I dont trust any format.

[AaronLuz]

Absolutely.

To store data indefinitely:

1. Store data in digital format.
2. Create perfect digital copy.
3. Repeat.

Why even bother trying to save CDs for 50 years?

Re:I dont trust any format.

[gweihir]

Have a look at MOD. I use them now for 6 years for backup and long-term storage. Never lost a single byte.

For other media I have made the same experience as you.

Re:I dont trust any format.

[whovian]

Punch cards don't corrupt

You haven't heard about the state of Florida voting results in the last US Presidental election, have you?

Re:I dont trust any format.

[ManxStef]

From the sounds of things you *do* trust a format: your hard disk! What would happen if that died? D'you have and redundancy on this such as RAID-1? If so, what'd happen if you got a virus that wiped everything? Tape/CDR/DVDR archival backups?

Spare disks sometimes count but only if the documents are never going to change and the disk is archived, otherwise there'll always be a "newer version" and it'll most likely be on your primary disk (which may be a point of failure).

Not trying to be pendantic but hard disks are not infallible, I've had plenty die in my time.

Re:I dont trust any format.

[Jeff DeMaagd]

Indeed, hard drives often don't last as long as removable media. If the hard drive fails, it isn't as if you can remove the media and just put the platters in another drive. Well, it is possible but I hear it is pretty expensive to do this and risky too.

The key I guess is to keep a spare drive in a second system and backup routinely and replace the drive as a routine. That may not allow for rolling back to a particular date (virus, discovery of otherwise corrupt files, etc), like the standard tape backup cycle often allows.

Re:I dont trust any format.

[tuffy]

A spare external hard drive for backing up data isn't a bad choice for home use. They're large enough now, and can be fast enough when using USB2.0/Firewire to make the process largely painless. And, most importantly, they can be kept turned off most of the time - which prevents accidental or malicious destruction of data. Of course, then one has to consider the possibility of fire or some other disaster taking out your house as well as your drives. In those cases, one has to weight the risks against the cost of protecting against them and the value of your data.

But I consider an external drive or two to be good enough, at least for the stuff I have.

Re:I dont trust any format.

[RenaissanceGeek]

Punch cards don't corrupt!?!

Tell that to the organizations that stored their punchcard archives on site, in the basement, and had them EATEN by termites!

Any storage media that we use that can be considered "food" (any hydrocarbon-based substance, including the plastic that CD's are made from is vulnerable to attack by fungus) has to be considered temporary storage. (and salt mines have a nasty tendancy to be geologically unstable: we know much of what we do about the Celts by finding trapped Celt salt miners sealed underground)

Re:I dont trust any format.

[Simonetta]

I keep everything on the hard disk. Luckily the size doubles every few years,...

I agree with using the hard disk as best backup. The size is small for the amount of data held and the access time to huge numbers of files is only thousandths of a second.

Hard disks have also inherent disadvantages. They are extrememly fragile, they must be screwed into the PC and be connected by confusing cables before use, the cost-per-megabyte is still eight times greater than removable optical disks like CD-R and DVD-R, and they can lose all of their data at once if the index gets corrupted.

I recommend that everyone take all their life documents, financial data, family photos, and career documentation and put all this data in encrypted form on inexpensive CD-Rs and DVDs. Place one in the glove box of your car. Send one to trusted family members or parents. Put one in a safe-deposit box either at your local bank or in a different country. Put the de-encryption passwords in your legal will, so your estate executors can get access to your information on the encrypted disks.

If for some reason you are forced to be living under an assumed identity, have another complete identity ready on a CD-R in your car or suitcase/backpack. You don't want to be in a situation where you find the police or the Migra waiting for you to come home and you're having all of your alternate identity papers inside the house. Make sure that the resolution of the scans of your alternate ID papers is good enough to recreate credible documents. With current 2400 DPI scanners selling for $100-$150 US, that shouldn't be a problem.

If something happens to the original papers or photos, then your records won't be lost. I've had friends lose their jobs and had all their personal papers and photos destroyed by callous landlords or vandals. I've seen (after living in California) people lose all their family records, life documents, and photos after fires, earthquakes, mudslides, floods, you-name-it.

We finally have low-cost tools to back up and recreate our lives. It would be a pity not to use them.

Re:I dont trust any format.

[Endive4Ever]

You forgot to mention that we all need to keep spare alternative-alternative identities on hand, too, in case they catch up with us and snatch our identities and our alternative identities at the same time.

They're watching, and it's important to keep ahead of them.

*twitch*

Re:I dont trust any format.

[markmoss]

Normally punch cards are punched with machines that actually cut the chad right out of the card and push it into a waste bend. You don't get hanging chad with that. You might drop the card deck, lose cards, etc., but as long as you keep them in order, and don't bend, burn, or get them wet this kind will read back properly every time.

That's if you keep the card reader working right - at the college computer center where I worked in 1972, a repairman had to come in and basically rebuild the card reader once a week, or it would start chewing up the cards and spitting the mangled pieces out on the floor. I'm guessing that was a few hundred thousand cards read between repair calls. At 80 bytes per card, it was a fair amount of data in those days, but not much by modern standards. This was an NCR card reader. I think IBM makes much better ones - but you'd still need a lot of punch and reader maintenance and a truckload of cards to back up a 10Gig hard drive. If you really want to use punched media for long term data storage, paper tape might be a better bet. It's more compact, it stays in order by itself, and the machines are simpler and therefore more reliable. And you can use mylar tape instead of paper, if it will last longer.

The other kind of punchcard, used in election systems, is pre-punched to leave each chad hanging by 4 threads of paper. The voters are supposed to push the chad out with a hand-tool. In 1972, the local electric company (or something like that) was using cards like this that the meter readers punched by hand as they read the meters. That computer center had a contract to process this data, but we hated those cards. Even though the users were trained (unlike voters) in how to be sure the chad was punched clean out and not left stuck to the card, you got little bits of paper fiber coming loose and clogging up the machinery. You also got chads that hadn't been punched breaking loose or swinging sometimes, so if you ran the deck through again it would read a few more holes, with maybe one or two of the old holes covered up now.

So there were three issues in Florida. One was that quite simply this was a system with an acknowledged read-error rate around 2% even under the best circumstances. In a recount you'd get a different count every time you ran the cards through again. This had been known for decades, but no one cared until they got an election so close that it mattered.

Second, voters were not trained in using the hand-punch sticks, and the flexible backing that is supposed to support the card while you punch it may have been worn-out or misaligned in some cases so they couldn't get a clean punch on the first try. Someone who understood the system would have checked the backside of the card and pulled off any hanging chad, but with a bunch of octogenarians that have never even programmed their VCR...

Third, Palm Beach in particular had a badly designed ballot. They should have known this, because in 1996 a similar butterfly ballot apparently cost Dole 19,000 votes. It wasn't enough to change the results of that election, and the Dems that run Palm Beach didn't learn anything from it because only Repubs were hurt. (I generally love it when the Demoncrats shoot themselves in the foot, but not when they make a joke out of the most fundamental underpinnings of our republic...)

See Ask Tog's article on this.

Re:I dont trust any format.

[Doppler00]

Make sure that the resolution of the scans of your alternate ID papers is good enough to recreate credible documents. With current 2400 DPI scanners selling for $100-$150 US, that shouldn't be a problem.

2400 DPI? You wouldn't actually scan an 8.5x11" paper at that would you? Unless you want to save a 500MB file for each document.

Re:I dont trust any format.

[Gumber]

What do you do about disaster recovery?

Re:I dont trust any format.

[Simonetta]

2400 DPI? You wouldn't actually scan an 8.5x11" paper at that would you? Unless you want to save a 500MB file for each document.

I didn't do the actual arithmetic so the file size might be in that range for a 8"x11" scan at 2400 DPI. I live in the US with US citizenship so I don't have Migra problems and I'm not all that familiar with the techniques of forging ID documents.

My main point with the message is that few people make the connection between having a high-resolution scanner and the possiblility of using it to scan all their life documents (birth certificate, family records, ect) and cherished photographs. Combine that with inexpensive CD-R and DVD writers to back up and store these scans inexpensively in multiple locations.

It's a suggestion to use all this new computer equipment in unexplored and unconceived applications. And yes for the millions of people in the USA without legal papers, it might not be a bad idea to use this new technology to keep a back up ID or two in a cheap and high density media format. If DVD recordable disks appear in 8cm format like the mini CD-Rs have, this might be an optimal data storage medium. Small, dense, light, and very inexpensive while not durable or scratch resistant.

Re:I dont trust any format.

[molafson]

If for some reason you are forced to be living under an assumed identity, have another complete identity ready on a CD-R in your car or suitcase/backpack.

Yes, I will see to this as soon as I bury those barrels of water and diesel out in the desert, stockpile 10,000 rounds of anti-aircraft ammo, and prep my 10 year supply of tinfoil berets. :-)

Re:I dont trust any format.

[ncc74656]

2400 DPI? You wouldn't actually scan an 8.5x11" paper at that would you? Unless you want to save a 500MB file for each document.

An 8.5x11" scan at 2400x2400 dpi, 1 bpp takes a bit over 64 MB. Compression (you could use something like Group III fax compression or PNG here) would no doubt reduce the image size significantly. Such a scan would easily reproduce text or halftone images pretty accurately.

(That said, it's still overkill most of the time. 600 dpi is often good enough. A higher-resolution scanner is more likely to do a better job at lower resolutions than a lower-resolution scanner that's running closer to its operating limits.)

Re:I dont trust any format.

[Wolfrider]

Magneto-Optical-Disc? Which brand?

Re:I dont trust any format.

[Simonetta]

Yes, I will see to this as soon as I bury those barrels of water and diesel out in the desert, stockpile 10,000 rounds of anti-aircraft ammo, and prep my 10 year supply of tinfoil berets.

C'mon, a new ID is much cheaper, and (to follow the original thread) much lighter to carry around.
Besides, wouldn't it be just a lot, well, easier, to change into a Canadian when you're in a place where the locals have been conditioned to believe that the Americans are responsible for everything that's wrong in the world?

Re:I dont trust any format.

[Master of Transhuman]

You mean virtually every other nation on Earth?

Re:I dont trust any format.

[Zillatron]

Punch cards don't corrupt althoguh I found MANY ways to screw them up

1) Spindle
2) Fold
3) Mutilate
4)...

I'll leave the karma poor to fill in #5 for fun and...

Re:I dont trust any format.

[MrRTFM]

I still use CDR's at home at tapes at work - cyclic backups with offsite copies. Its just that I dont trust them.

The only time I would need to restore from them if something really horrible happened, like a missile hitting the building (in which case I probably wouldnt care). My point is that, its better to have all your old backups online on multiple hard drives/ servers because the data is there in a known state - if your HD goes bad, you know about it fast, and can start restoring from recent backups, but if your 12 year old tape goes bad you might not know about it for another 5 years.

Re:I dont trust any format.

[gweihir]

Does not matter. They are ISO-standardized. All brands are extremely reliable.

When I was young...

[cwernli]

For CDs especially do not:
2. Use a pen,pencil,or fine-tip marker to write on the disc.

When I was young, we didn't have those fancy automatic CD burners, we had to manually write to them. And if you made one error, you had to walk 20 miles through a blizzard to the "local" dealer.

Re:When I was young...

[devnullish]

Heh, you had it easy! When I was young we had to make our own CD! We had to extract the materials from the Earth and with our own two hands mold them into a perfectly flat and perfectly balanced CD. And if we failed we had to walk 60 miles in a blizzard to our local extraction plant for more minerals up hill - BOTH WAYS! Whippersnappers!

Re:When I was young...

[TREETOP]

At least you have a CD recorder.... in my day, we had to record the data in a open source called "print" in one of hundreds of languages. And the medium was called "paper" and we used a chemical tool called "pencil" to "write" the data.... you young kids got it so easy.....

Re:When I was young...

[Tom_Yardley]

Oh, paper... I'll tell you, we dreamed of having paper. You were lucky. We were so poor we had to write on tablets of clay.

Re:When I was young...

[Reziac]

In MY day, we didn't have any of this fancy data storage crap. We had to memorize all the data ourselves, and it wasn't even neatly categorized in ones and zeros either!

caddy & military cases

[formalS]

Remember the days that cd roms where kept in caddies which were put into the cdrom reader. According to the guidelines this was a much better solution. Are these caddies and these special cd rom drives still available (new, not second hand) ?. Would be a market for professional users. I use a miltary case, used for storing munition & bombs, for storing my floppies. Since these metal cases are waterproof (and so protect against dust as well) they can enhance the life om my valuable cdroms as well.

Re:caddy & military cases

[touch0ph]

.50 Caliber ammo boxes seem to work best, as far as size. You can conviently fit two CD case holders inside.

Re:caddy & military cases

[T34c3r]

As someone who routinley used ammo cases (metal ones- Vietnam era-->late 80's + 90's) for storage of tools, parts, and other vehicle related stuff I've seen a lot of them. Many ammo cases still have a light film of a waxy substance inside (along the corners especially). This waxy film traps water easily (rusty tools...eventual CD degredation). I suspect it can also harbor bacteria, mold, etc.... Not ideal for long term CD/DVD/DAT storage. If you still like ammo cases, check out the *newer* cases for 50 cal. and AR-15 ammo. These are made of a a tough plastic material. And withstand abuse much better.And no waxy film. As a bonus they stack *much* better.....

Re:caddy & military cases

[formalS]

You may be right about the wax. I used the metal cases because they protect against electromagnetic influences. That was my major concern. There are loads of pc screens, pc's and the like here... Anyway, these cases will live as long as I don't throw them away. It may help to put the cd's first in a sealed plastic bag. Thanks for your information.

Re:caddy & military cases

[chiph]

What if you include a pouch of silica gel in the metal ammo can with your CD's? Chip H.

Google's cache

[iamthemoog]

http://www.google.com/search?sourceid=navclient-me nuext&q=cache:http%3A//www.itl.nist.gov/div895/car efordisc/CDandDVDCareandHandlingGuide.pdf

Just in case light, moisture, radiation, scratches, marking, adhesive labels or whatever have got to their server....

Re:Google's cache

[HTH NE1]

That google cache link was very helpful to me as for some reason page 5 on of the PDF came through as blank pages, save for the occasional table lines, rule lines, and images. Even the onepage summary PDF came out blank in xpdf. (I so wish stories would offer text-only versions of PDF links more often.)

And now I can do a search and see they have no mention of my method for labelling these disks: a black wax pencil purchased at an art store. Well, apart from their general advice to not use pencils, though I'm not confident they've tested all kinds of pencils.

Sharpies?

[Anonymous Coward]

Do Sharpies count as solvent based? What sort of marker can I actually use? Brand names, please.

Re:Sharpies?

[patmfitz]

Yes, Sharpies are solvent-based. Look for water-based inks.

Re:Sharpies?

[Geccie]

From the sharpie web site FAQ

Is the SHARPIE marker safe for writing on CD's?
Sanford has used SHARPIE markers on CDs for years and we have never experienced a problem. We do not believe that the SHARPIE ink can affect these CDs, however we have not performed any long-term laboratory testing to verify this. We have spoken to many major CD manufacturers about this issue. They use the SHARPIE markers on CDs internally as well, and do not believe that the SHARPIE ink will cause any harm to their products

They may contain solvents, but you're probably safe if there is plastic covering the metal burn layer. If the layer is exposed, do not write on it with a solvent based marker. It may react with the solvent and decompose
Here's a previous post on the same thing
http://slashdot.org/comments.pl?sid=85127&t hreshold=1&commentsort=0&tid=137&tid=198&mode=thre ad&pid=7423266#7423988

Black felt marker?

[nacturation]

How does the use of a black felt marker affect CD longevity?

Re:Black felt marker?

[devnullish]

Write on the bottom of the CD and I'll show you ;)

Re:Black felt marker?

[vacuum_tuber]

Right udner the "Spel Chekc" optoin.

Re:Black felt marker?

[Anonymous Coward]

you make no sense, chemo sobby

Looks like CD storage racks got it wrong then...

[rklrkl]

If you are looking for a CD storage rack for your music CDs, almost all of them appear to stack the CDs one above the other (i.e. the CDs lie horizontally), which clearly helps to save space. However, now we're told "do not store discs horizontally for a long time (years)" ! So have almost all the CD storage rack manufacturers got it 100% wrong for two decades then?

Digital Preservation

[SteveTheRed]

I'm backing up all of my data onto 8-track tapes and storing them on the dashboard of my car. They will be safe forever there...

I'd have to argue...

[devnullish]

light, moisture, radiation, scratches, marking, adhesive labels

Light can make pretty colours on your walls from the reflection off a CD.
AOL CDs make cool coasters - so moisture is good!
Radiation - anyone try putting a CD in a small bowl of water, putting a paperclip on it and putting it in the microwave?
Scratches - Two words(acronymns): AOL CD
Marking - See Scratching
Adhesive labels - but what other kinds of labels can you get? Surely the adhesive types are preferable to the kind that aren't adhering. I mean if I put a CD in a drive with a label that didn't adhere, I'd ruin the drive alot faster than with an adhesive label.
This was only a test (of my idiocy). Had this been a real example of my idiocy, someone would have killed me by now!

Re:I'd have to argue...

[Flounder]

Just in case I actually do put a CD into a bowl with a paperclip and put them in the microwave, can I get your name and address? I'm gonna have my kids do it, and then sue you for child endangerment and contributing to the deliquency of a minor.

j/k, I'll just do it myself then hire the lawyer that did the McDonalds coffee lawsuit. Be seeing you.

As time goes on...

[Anonymous Coward]

I've had floppies, CDs, DATs, Zip disks and even tapes go corrupt over time.

And the older you get, so will your penOr.

Best for floppies...

[Anonymous Coward]

"I've had floppies.. [go bad] over time."

The solution... VIAGRA!

Guide to Analog Preservation from LoC

[O]

Digital is great, but what about all of that 'legacy' analog media you have lying around, like pictures, books, tapes, and LPs?

The Library of Congress has a guide right here!

Re:Guide to Analog Preservation from LoC

[Anonymous Coward]

Im still waiting for the hole punch to make my CDR's double sided!

(re: C64 floppies)

DRM

[wrmrxxx]

Knowing how to store data for a long time might not help you much if you can't read it back in 20 years because some twisted DRM scheme stops you.

Can't wait!

[killermookie]

Boy, I can't wait to use my ??? on my ??? in the future!

Re:Can't wait!

[Anonymous Coward]

Boy, I can't wait to use my ??? on my ??? in the future!

Sounds profitable.

Re:Looks like CD storage racks got it wrong then..

[Teddy Beartuzzi]

That's the one I don't get. Isn't all the data going to slide off if I store it vertical?

Anybody who was able to get the 50 page article know why doing the horizontal bop is bad?

is CD still a backup media?

[claudebbg]

I'm personally really serious about backups (all my important non-legal documents are stored on computers). I've been doing backups on a lot on CDs but realized:

• a double backup is necessary if I want "cold" backup
• burning CDs takes time (for example, I've got 6GB of apps/OS)
• from time to time (2-5 years), a second generation has to be done
• external disks are becoming a bit more affordable (around $1.5/GB, which means less than a dollar for a CD space)
• disks are really fast (seconds instead of minutes for CDs)

I'm currently leaving CDs for backups and "just" using HD backup (from my laptop to my desktop for online backups and from my desktop to an external HD for cold backups). CDs become moving support to bring files to friends (so no long life implied).
I've made simple rsync scripts (rsync over ssh for laptop to desktop wireless communication, rsync from disk to disk for desktop). This solution implies good data organization (basically live/shared/cold) but is really fast, simple and up to date.
Are there other ./ers moving that way?
I'm currently planning a bigger (200-500GB) solution based on Firewire drives (I'm using Macs, but it also works on PCs). Do you have any advices/experiences on using those solutions in simple home network?

Re:is CD still a backup media?

[neko9]

i'm making double backups. even triple and more. and on cd-rs from different manufacturers. so chance is bigger that i will get my data back in future. i don't think keeping backup on hardware with so many mechanical parts (and constantly operating) is more failsafe than cd-r or mo.

Re:is CD still a backup media?

[Anonymous Coward]

My home directory has been based on symlinking top level sub dirs (ie: ~/dir1 ~/dir2) to a common location where I have another hierarchy that is capped at 650MB or so.

~/cds
~/cds/cd-lib
~/cds/cd-media
~/cds/cd-tm p
~/cds/cd-work

Then:

~/lib --> cds/cd-lib
~/tmp --> cds/cd-tmp
~/work --> cds/cd-work

(Actually, I have a time-date thrown in between
cds and the cd-*, but that's skipped here).

I then have a script that will step down the ~/cds
directory and write out each cd-*. I also rsync ~ to multiple machines.

My home directory is the same on all my unix machines. In fact, my paths are 100% the same, on all my unix machines -- even where I do not
have root.

All cds are indexed (ls -Rl, etc) and put into ~/cds/#INDEX/cd-#.gz
That is, each CD is numbered and the contents are put into an individual file for each CD. I then combine all the .gz files into "all.gz" ... and a simple shell script can scan for any filename on any of my cds and spit out the cd index #.

I currently have about 2.5 million personal files from about 1987 until present.

I recently purchased 200 taiyo yuden cds and plan to duplicate my entire library, as well as continue to make schedule cd burns.

Re:is CD still a backup media?

[WuphonsReach]

As long as you're using (3) external drives, rotated periodically (child-parent-grandparent scheme), with at least one of the three stored off-site... you're reasonably secure.

You should still be burning snapshots / archival material off to DVD-R periodically with the idea that if you lose a single disc you don't lose everything. The contents of the DVD-R should be protected by recovery data so that even if the media gets badly scratched, you'll have decent odds of being able to repair the damage. (And if you store all of the files in a single folder with tar/zip, with a single parity set protecting them, you can even recover the data if the table-of-contents gets damaged.)

Re:is CD still a backup media?

[Jeff DeMaagd]

One thing to keep in mind that you'll want a backup that is routinely disconnected from the computer. Heck, some people had reported problems with upgrading to MacOS 10.3 where certain Firewire controllers went nuts and blanked several user's Firewire hard drives.

I have read through most of the pdf. It looks to be mostly a compilation of data from a great many sources that aren't from organizations on the level of NIST. I thought they were doing some testing, I had hoped to read about accelerated aging & testing methodologies as well as see some actual testing data and how they derive life expectancies.

Unfortunately, the author used "Amaray" as a general description of plastic DVD keepcases and not distinguished it from the "Amaray" brand DVD keepcase.

Re:is CD still a backup media?

[gillbates]

I'm kind of interested in what you are doing. I have a similar problem - I've got a large set of data that needs to be shared between work, home, and laptop machines. It's constantly a pain because I've got different versions of the same files on different machines, and backup is a real problem.

Supposing I have the most recent version of file A.cpp on the home machine, and most recent version of file B.cpp on the work machine, if I have to restore the laptop, I'm in a real crunch. I won't get the most up to date versions of every file - rather, I have to choose which is most likely to be more up to date, and then restore the out of date files from the other backups by hand.

Rsync did look promising, but I can't use it because it can't run correctly on Windows (in Windows, a user program cannot set the modification date on a file without actually writing to the filesystem tables. The UNIX API's for setting mod time simply return -1 with every call.) I've tried writing my own utility, with moderate success. Given that I can't set the date on a file, I can only synchronize two sources, not three or more.

Re:is CD still a backup media?

[ingenuus]

I assume using the win32 api SetFileTime was out of the question?

BOOL SetFileTime(
HANDLE hFile,
const FILETIME* lpCreationTime,
const FILETIME* lpLastAccessTime,
const FILETIME* lpLastWriteTime
);

Theoretically, cygwin should transparently use this or you could modify rsync to use this... or maybe I'm misunderstanding you.

Re:is CD still a backup media?

[gillbates]

Well, yes. The problem is that the Win32 compilers don't support the directory traversing API's that UNIX does, and I was trying to write something portable that could be compiled with both gcc and DJGPP. Yes, I could have gone Win32, but I would basically have two different codebases for the differing platforms. Generally speaking, anything that relies on the Win32 API's can't be ported without substantial effort.

what are we made of?!

[Anonymous Coward]

"Do not: ...
8. Expose recordable discs to prolonged sunlight..."

in other words, make no change in your lifestyle whatsoever.

Re:what are we made of?!

[vacuum_tuber]

Sunlight?

Is that the stuff that pollutes the environment "outside" while I'm asleep inside?

--
"Outside??? You mean... DOWN THE STOOP???"
- Nero Wolfe

Gee, NIST forgot a lot of things

[Rosco P. Coltrane]

And if you only want to know how to care for your precious data, there is a one page summary.

They forgot a lot of useful tips. Here they are:

DO:

- not write anything on CDRs. No Data means no data to lose

- use a felt-tip marker to write your data in readable hex format on the label side of multiple CDS, as a backup.

DON'T:

- use your CDs as freesbies to play with the dog

- use your CDs as under-glasses

- punch a hole on the side of the CD to hang it on your key ring

Re:Gee, NIST forgot a lot of things

[Krapangor]

punch a hole on the side of the CD to hang it on your key ring

CDs/CD-R are written from center to border. So if your CD(-R) isn't completely full you can actually get away with this. This effect is also used for "shape" CD's.
The only system which has problem with these is FreeBSD due to the IO shedular, I think.

Re:Gee, NIST forgot a lot of things

[Anonymous Coward]

If you punch a hole in a CD, at the speed it rotates in a modern drive, you have every chance of ruining the drive because of the vibrations, or having the disk explode in it.

Re:Gee, NIST forgot a lot of things

[BigJimSlade]

- punch a hole on the side of the CD to hang it on your key ring

But can I still cut the write-protection notch in the CD so I can write to the other side?

Timely article...

[Jin Wicked]

I've been shopping for the best brand of CD-RW I can find for longevity, and I'm going to be backing up all my extremely high dpi scans to disk, twice, and storing a set in seperate locations. I sell my original artwork, so this is important to me. I'm glad to know I shouldn't be stacking these vertically. I don't care much about my music CDs since I rarely buy them new or pay more than $5, and keep them in a large binder w/out jewel cases... but my personal data is certainly more important. From now on I will keep my backup data CDs in proper cases and store them as recommended. I'd also like to know which markers are safe to use. I've always used Sharpies in the past.

I also back everything up to the second hard drive in my system, but when dealing with 50-75MB files that can become impractical quickly. I'm paranoid now because I've been through several hard disk failures this year alone.

Does anyone recommend a particular brand of CD-R(W) disks best known for longevity, while on the subject...?

Re:Timely article...

[Anonymous Coward]

and I'm going to be backing up all my extremely high dpi scans to disk, twice, and storing a set in seperate locations.

Yeah, it sure sucks when your collection of porn mags doesn't fit under your bed anymore.

Re:Timely article...

[Jin Wicked]

How original and funny you are. If I wanted to see anything that might be in Playboy I could just go take a bath, because I'm a busy chick without time for pr0n. You also conveniently ignored the part where I mentioned I was backing up my own artwork. Just because I might enjoy drawing boobies does not make it pr0n0graphy.

So nyeh.

Re:Timely article...

[donheff]

I haven't read the article so I may be misleading you, but a comment above says that the guide recommends the opposite of what you concluded. You should store your CD's vertically, not horizontally. A supporting reply to the comment quotes a section of the guide that appears to support the "store em verticle" practice.

Don

Re:Timely article...

[fafaforza]

C'mon. Get a sense of humor. In either case, I don't think the joke was aimed at you specifically. It was just a general joke. The opportunity was there and someone took it.

Re:Timely article...

[kayen_telva]

taiyo yuden

taiyo yuden

if that link doesnt work then just search your favorite shopping site for them

Re:Timely article...

[Neon Crossing]

About storing them horizontally... Is that only harmful when they're in the cases? I keep my CD's in a binder, which I know will be flat nearly all the time. So is it just the fact that they're in cases that causes the horizontal problem?

Re:Timely article...

[Pope]

Why are you using RWs for permanent backups? -Rs are your best choice, since the changes are basically undoable, unlike RWs.

Only suggestion is to avoid super-cheap -Rs, and burn at slower speeds, like 4x or 8x.

Re:Timely article...

[warkda rrior]

Does anyone recommend a particular brand of CD-R(W) disks best known for longevity, while on the subject...? Kodak Gold CDRs and Mitsui (Archive) Gold CDRs are quite good, if a little expensive (prepare for $1+ per CDR).

Re:Timely article...

[WuphonsReach]

TY's (as the other posted commented) are reported to be the best CD-R / DVD-R that you can get. You should probably ditch the CD-R format and switch to using DVD-R instead. Mostly due to storage space and having to deal with only 1/7th the number of discs. Best place to get TY media is online (search the alt.video.dvdr newsgroup at google).

In addition you should be looking to add parity/recovery data to your CD-R/DVD-R backup files, which serves two purposes: (a) allows you to verify that the files are still readable and intact (b) allows you to recover damaged files if you have enough recovery data. It allows you to recover from scratches that the underlying ECC was unable to correct for.

The easiest product to use right now is called PAR or PAR2 (I prefer QuickPar). Basically, put all of your files in a single folder (or zip things up into seperate archive files and put those in a single folder) and then use QuickPar to create recovery data. For a CD-R, I usually collect around 650Mb of data together, and then create another 45Mb of recovery data. For DVD-R, I do 4Gb of data and 0.35Gb of recovery data.

Re:Timely article...

[toddestan]

My experience with CD-RW's is they get less reliable as the speed goes up. I have a bunch of 8-10x rewriteables, and it seems like about half of them have failed. Meanwhile, some old 4x ones just keep going. As for brands, I have found the Sony disks seem to last longer than the others.

But if I was you, I'd just burn to CD-R's as they are a lot more reliable.

Re:Timely article...

[srleffler]

I suspect a binder will be worse. A jewel case holds the disc firmly in the middle, with (ideally) nothing in contact with the recording surface. For long-term storage you definitely don't want anything in contact with the recording surface. Putting a disk in a soft plastic sleeve in a binder sounds like a sure recipe for eventual failure.

Re:Timely article...

[Wolfrider]

--I've had good results with Taiyo Yuden ("FujiFilm") brand CDR-700 discs.

-DON'T buy Memorex "high-speed" CDRW tho, they crap out after about 10 rw's.

Re:Timely article...

[ManxStef]

Extremely high DPI scans are usually more like 350MB upwards (for 35mm colour film anyway), standard A4 paper sketches/drawings may hold less data? It may be worth getting your work scanned with the best flatbed you can find - Agfa have always made excellent professional colour-profiled devices but there are plenty other to choose from (*make sure* you profile the device as generally colour accuracy is as important as resolution). If you know a graphic designer they'll have access to one of these or know someone who has (unless you've aready got one that is!).

I'd also advise getting your work photographed, if possible, as an analogue backup. If you know any pro photographers they should be able to do this for you - it's fairly easy: use a tripod, high quality prime lens (the best primes tend to be sharper than zooms and with less distortion), colour-balanced lighting, high res. archival slide film (negative doesm't archive well), shoot a colour test and gamma chart on the first frame so you can gauge the characteristics of the film, etc. A pro will know all this anyway, and it's actually a remarkably cheap process if you've got a knowledgeable friend :)

You can also get this film scanned at 5400dpi upwards (drum) - it'd be interesting to compare these to the flatbed results! Anyway, there's plenty of advice on archiving photographic film on photo.net and this, while not perfect by any means, is an excellent backup "human readable" medium despite its flaws.

As for the highest quality CDs? Over at cdfreaks.com I gathered the following info:

(Copying from an article by "Halcyon" below - sorry I can't find the URL right now)

Verbatim DataLifePlus CD-R 700Mb 24X Super AZO
- Test winner of the PC Professionell 3/2002. Lowest number of errors. It also has a decent label side protection although not on the level of Basf/Emtec Ceram Guard. The best amongs disc tested in regards to aging related stability.

Teac CD-R 700 MB 24x
- Very good disc, with amongst the most lowest inherent error levels of all discs tested (especially at higher writing speeds). Test winner of PC-Welt 1/2002. Lowest number of errors.

Basf Ceram Guard 1-12x (older - some stock still around)
EMTEC Ceram Guard 1-24x
- Both of the above are essentially the same, although the Emtec 24x version is a later batch and has a higher writing speed grade. Both manufactured by Tayio Yuden (one of the best). In addition they have a VERY TOUGH ceramic coating on the label side (where CDs are most vulnerable to scratches). This is the disc I use myself out of the consumer brand choices if I want a copy that must tolerate normal handling without starting to develop errors.

TDK Reflex Ultra CD-R 80 24x
- Very good tested quality in PC Pro 3/2002. Tayio Yuden manufactured.

Sony CD-R 700 Mb CDQ 80 N2 24x
- Very good tested quality in PC Pro 3/2002. Tayio Yuden manufactured.

---

Oh, and Philips Silver Premium are supposed to be among the best too, as are the Kodak archival gold's (but they're no longer manufactured unfortunately).

Hope that's of some help!

Re:Timely article...

[vacuum_tuber]

donheff wrote:

...a comment above says that the guide recommends the opposite of what you concluded. You should store your CD's vertically, not horizontally.

The poster didn't mean what he wrote. When he wrote "stacking vertically" he meant that he had been keeping them in vertical stacks of horizontally-oriented CDs/DVDs.

Then again, maybe he did completely misunderstand the recommendation. Unfortunately a lot of people today speak ambiguously. Maybe it comes from the contamination of language introduced by politics, where some now call a tax an "investment" and a reduction in the rate of increase of a budget a "cut."

Re:Timely article...

[bill_mcgonigle]

--I've had good results with Taiyo Yuden ("FujiFilm") brand CDR-700 discs.

Right, but you have to be careful these days. The Taiyo Yuden's are made in Japan. Lots of FujiFilm is Taiwan these days, so who knows what you'll get.

At Best Buy only the 30-pack of FujiFilm is made in Japan. I use 'em for my archival stuff. I use the crappy ones for data transfer 'cause I don't care if they're dead in 2 months.

Am I wrong or...

[Anonymous Coward]

CDs reliability (I mean new CDs) is decreasing year after year like ATA hard drives?
When audio CDs were introduced, about 20 yrs ago, I remember magazines doing tests like making holes on the surface with a drill, then telling how amazing were the error correction systems; and now we're told not to touch them?

Oh for God's sake

[Anonymous Coward]

Here is the same thing posted anonymously. Mod up this one instead if you feel so strongly about it.

You Fsck Nut...

[devnullish]

Thank you for your kind words. I promise to try better in life and maybe, if I am very lucky I will oneday have as broad a vocabulary as you do.

I've known sailors with a larger vocabulary and more colourful too!

Re:You Fsck Nut...

[Anonymous Coward]

I've known sailors with a larger vocabulary and more colourful too!

I'm sure you have!

Re:Looks like CD storage racks got it wrong then..

[mobby_6kl]

from the 50-page pdf:
Physical mishandling of the disc is usually the cause of polycarbonate*
layer damage. The polycarbonate may also flex or bend if
stored for a long period of time in a nonvertical position.
and
Long-term horizontal storage, particularly in a
heated environment, can cause the disc to become permanently
bowed. While the data may still be intact, the disc may not operate
properly in the drive or permit the laser to follow the track.

*3.1 Polycarbonate (Plastic) Substrate Layer
The polycarbonate substrate makes up most of the disc, including
the area that is read by the laser (opposite the label side on CDs). It
is present on both sides of a DVD, even a "single-sided" disc with a
label on one side. This substrate provides the disc depth necessary
to maintain laser focus on the metal and data layers. It also gives the
disc enough strength to remain flat. Anything in or on the polycarbonate
layer that interferes with the ability of the laser to focus on
the data layer will result in the misreading of data. Accordingly, fingerprints,
smudges, or scratches, as well as such substances as dirt,
dust, solvents, and excessive moisture (which polycarbonate will
absorb), can interfere with the ability of the laser to read the data.
Contact of any foreign material with the polycarbonate substrate
layer should be avoided.

Re:Looks like CD storage racks got it wrong then..

[Flounder]

Just like the proper method for storing LPs. I built my own DVD and CD shelves, and they're designed to store the media vertically. Plus, building them was the only way to get shelves like the ones I built for my LP collection.

Re:Looks like CD storage racks got it wrong then..

[P-Nuts]

I don't really see why storing discs horizontally should matter. I can see it would be bad to have a huge pile of them as the weight of all the ones on top might squash the ones underneath. Though a jewel case ought to help with that quite a lot. And in a storage rack, the cases sit on individual supports anyway.

The only thing I can think of is that the CD, supported only at its centre in a jewel case, might very slowly bend under the weight of the edges, becoming slightly convex as viewed from above. This wouldn't happen if the CD were vertical.

Every five years, move your complete library

[heironymouscoward]

Media capacity follows the standard technological growth curve (aka Moore's Law) so that it is both convenient and practical to move your entire library every few years.

Thus my MP3 collection has migrated over time from Jaz cassettes to CDR to large hard disk to DVD.

Apart from the practical aspects of finding a reader for old media, the sheer space taken by old media (e.g. my twenty-odd Jaz cartridges) makes it useful to move regularly.

My MP3 collection, freshly re-created from my original CD collection, fits onto ten data DVDs while it would require about 70 CDRs.

Doing this, while also keeping multiple archives on hard disk (CVS mainly) means I have no problem accessing projects that I worked on 15-20 years ago. No way would I have confidence in diskettes or backup tapes from the same period.

Though I do have a 50cm-wide 150Mb removable Wang disk that has some interesting stuff on it if anyone has an old Wang VS lying around.

Re:Every five years, move your complete library

[Flounder]

Though I do have a 50cm-wide 150Mb removable Wang disk that has some interesting stuff on it if anyone has an old Wang VS lying around.

Sorry, I don't want to have anything to do with your old Wang. And stop lying about it's size. 50cm, yeah right.

Re:Every five years, move your complete library

[Anonymous Coward]

Hey, it's not the size of the wang that counts, it's what you do with it!

Re:Every five years, move your complete library

[Anonymous Coward]

Wow... wang jokes never get old, do they?

Re:Every five years, move your complete library

[Reziac]

"...both convenient and practical to move your entire library every few years."

Never imaged a few hundred floppy disks, eh? :)

I finally broke down and imaged all my old install diskettes, by now completely irreplaceable and some still necessary to my computing world. Took much of a week to image 2 CDRs worth of floppies, and that was with two machines working on it.

Yep, real convenient! :)

Actually, 360k floppies from 18 years ago are mostly still good (I have a few hundred of those yet to image :( But most 1.2mb and nearly all 720k diskettes died several years ago, and 1.44mb have been unreliable for 5 or 6 years as well (even new disks are often no good anymore).

Re:Every five years, move your complete library

[vacuum_tuber]

heironymouscoward wrote:

Though I do have a 50cm-wide 150Mb removable Wang disk that has some interesting stuff on it if anyone has an old Wang VS lying around.

I do have a Wang VS -- more than one -- and they're not lying around. One runs a Web server 24 x 7 and others are used for development, conversions, etc. I've never heard of a 150 MB removable disk, though, and certainly don't have a drive for one. I don't see anything in GENEDIT that even remotely resembles a 150 MB Rem. What vintage is it?

FYI there are still some Wang WIIS imaging systems in operation -- 12" and 5.25" WORM opticals. I wonder whether Wang and users of those systems thought the opticals were archival. I wonder whether they may have in fact been designed and built to much better standards than the CDs and DVDs being discussed here. Some of those systems have been in operation for about 15 years.

Re:Every five years, move your complete library

[vacuum_tuber]

Anonymous Coward wrote:

Wow... wang jokes never get old, do they?

I wish my organic wang worked as well as my Wang VS systems do -- they never quit or go down.

Re:Looks like CD storage racks got it wrong then..

[Animaether]

So have almost all the CD storage rack manufacturers got it 100% wrong for two decades then?

For long term storage purposes - apparently so.

For convenience purposes ( i.e. being able to read the little title on the side of the case ) ? Heck no.

Amazing.

[DarkHelmet]

This supposed guide on how to keep CD/DVD discs preserved reminds me of a story back in high school. A friend of mine (around 1997-98) carved his name onto his CD so that other people wouldn't steal it.

Of course, this bright individual decided to carve his name onto the UNDERSIDE of the CD, instead of the top side.

Before I knew this, I asked him if I could borrow the CD so I could rip it to mp3. When I saw the underside of the CD, I realized that there was no help for this person whatsoever.

I think White Zombie plus Acid does bad things to today's youth. Mostly acid.

The most amazing thing is that he graduated high school.

The main lesson here is to TRY and take care of your albums. Don't leave them out, let your kids throw them around the room. But then... this sort of thing is obvious to any doofus who has made it out of high school.

Oh wait...Nevermind.

Re:Amazing.

[ymgve]

Well, if you're first going to carve something into a CD, the underside is the best place to do it. Sure, it might make the CD unreadable, but that can easily be fixed with any CD repair kit out there. Carving on the label side, on the other hand, will give you a nice-looking coaster.

Re:Amazing.

[Orion442]

You can also fuck them up by carving your name on the label side. Found that out back in '90 :(

Re:Amazing.

[Anonymous Coward]

I think this depends somewhat on whether we are talking about a pressed CD or a CD-R. A pressed CD, I believe, has a nice layer of plastic on the label side, above the reflective layer[1]. CD-Rs have much less protection on top. Some appear to have *nothing* protecting the reflective layer - you can easily scrape it off with your fingernail.

So I think that in theory you should be able to scratch the label side of a pressed CD without doing any real damage to the data until the scratches get fairly deep. Even a very small scratch on the label side of a CD-R can be catostrophic, particularly because the reflective material around the scratch will start to peel and flake off. The unreadable area is probably considerably larger than the scratched area, and can continue to grow.

CD-RWs are more similar to pressed CDs. They should have a top layer of plastic as well, making them more resistent to label-side scratches.

[1]I haven't actually tested any of this very much, so it's based largely on what I've read about the construction of the different types of discs. Before posting I decided to test my theory about the top-layer of plastic on pressed discs by snapping an old AOL CD in half. I found that in this case there was no top plastic layer - the reflective layer appears to have the label printed directly on top of it. The whole layer/reflective layer peeled off quite easily after the disc was broken.

So maybe I'm completely wrong about the construction of pressed CDs or maybe AOL just uses extremely cheap discs. Actually, I'm sure the latter is true, but the former may be true as well.

Re:Looks like CD storage racks got it wrong then..

[hazee]

Couldn't you counteract the effects of any bowing of the discs by simply flipping them over every year or so?

Re:Looks like CD storage racks got it wrong then..

[nordicfrost]

So have almost all the CD storage rack manufacturers got it 100% wrong for two decades then?

Yes, but not of ignorance. Just because the horizontal design looks better in many cases.

they forgot the most important one...

[scatterbrained]

don't forget to protect against nature's most
destructive force - 3 year old boys on a sugar
buzz.

Heat and Humidity

[Pedrito]

I'm a little surprised that nothing was mentioned of the CD-eating fungus which has been discussed here a couple of times before. I have personally been the victim of that fungus and lost somewhere in the area of 20 CDs to it.

I live in Southern Mexico where it's hot and humid most of the year, and these conditions apparently make CDs very vulnerable to the fungus. Given that I don't have any environmentally controlled rooms in which to keep my CDs, what should I do? I'm really concerned that my CD-Rs will be ruined from the higher heat which, for most of the year is in the high 80s to high 90s.

I've considered putting my CDs and CD-Rs in the refrigerator, but I'm not sure how safe that is. Can anyone comment on that? My thought was to put them on a spindle and then place that in a ziplock bag, evacuate as much air as possible, and then stick it in the fridge. Can anyone comment on that? I'm afraid even with a little air in the bag, there will be enough condensation to cause a problem. If someone could give me some good advice on how to handle that, I'd really appreciate it.

Re:Heat and Humidity

[dlamming]

Putting them in a ziplock bag won't do all that much to protect against humidity. You want to put them in a sealed (with vaccum grease) glass or plastic vessel with desiccant, a water-absorbing material. That will keep your stuff cool and dry. They make cabinets that you can just put in your refrigerator.

Re:Heat and Humidity

[Anonymous Coward]

Silica gel dessicant can also be found/ordered from crafts-supply places; in large (by archival standards) quantities, it's used for drying flowers and the like.

You'd have to construct your own baggies for it.

Re:Heat and Humidity

[gordguide]

It's essentially what much archival storage consists of. It's best if you can dedicate a 'fridge to the job; that way you can set the temperature a little higher than what works for food. A properly set up fridge is cool, dark, and low in humidity; just what the doctor ordered. It might even survive a fire if you're lucky.

The spindle thing I would question, though. Close contact isn't a good idea. Try slim jewel cases, stored upright in a box, and cover the box with a garbage bag taped up. If you must use spindles, store them so the disks are upright.

If for some reason you need access to the disks, take the box out of the fridge, rip off the tape, and let it sit on the counter for a half-day or so to acclimatize.

You can store photographs, slides, important documents, rare books, and heirlooms there as well. Upright is usually better.

CDs and magnetic tape don't like it too cold; the rest love it, but any lowering of the temperature helps. Around 40F is probably a good compromise.

Re:Heat and Humidity

[DigitalCrackPipe]

That's a tough question - the fridge can be hazardous (as others mentioned) if you aren't careful with how you use it. I like the idea of a vacume sealed container because with no air, there should be no humidity.

I've never looked, but if you can get a humidor to keep cigars at the right temperature and humidity, you should be able to find items for evacuating air and humidity, and maybe even cooling.

or, maybe a vaccume sealed container in the fridge?

Re:Heat and Humidity

[Reziac]

How about a frost-free freezer, at its highest temperature setting (which can be around 40 degrees)?? They tend to dessicate food, so you'd think they might help with keeping other materials dry as well.

A ziplock bag might actually make things worse, since in my experience, they tend to encourage condensation. Something that absorbs moisture, like fibrous cardboard, might be better as a liner for another container.

Water-based markers are recommended.

[Futurepower(R)]

First paragraph, page 30:

"Numerous CD vendors have noted that the thin protective lacquer coating can deteriorate from contact with certain solvents in markers. To eliminate the risk, water-based markers are recommended for CD labeling. As a solvent, alcohol is generally less damaging than xylene and toluene, which are common in aromatic solvent-based markers. According to anecdotal reports, alcohol-based markers can be used to label CDs without causing performance problems. However, there are no explicit lab test results to show what effect solvents in markers have on different CDs or DVDs, particularly over the long term."

Misleading

[Transcendent]

The actually "guide" to care for your DVDs and CDs isn't 50 pages... it's about 2 pages of "do"s and "don't"s. The rest is just technical mumbojumo with the TOC, definition reference, bibliograpy, and other legal stuff at the beginning.

"WOAH 50 PAGES!" Well... yea... but the important stuff is only on a few of them.

So if you plan on printing this out for easy reference... save yourself the extra 48 pages.

Re:You fuck nut!

[Gilmoure]

Your not remotely funny.

It is not Your but You're. Just think before you post. Are making a contraction of You are or are you talking about one person's item? For example, Your stupid, overwraught, illiterate post. Notice that I did not say You're a stupid, overwraught, illiterate poster. That would be rude.

The answer to the question

[WormholeFiend]

G.W. Bush once asked "Is our children learning?"

The answer are clearly no:

"For those slashdotters who is not familiar with..."

Re:The answer to the question

[spanklin]

I've got post-thesis grammar cop syndrome, too: The scientists... have released an excellent 50 page guide on care and handling of CDs and DVDs for long term storage. For those slashdotters who are not familiar with the physical make up...

Re:The answer to the question

[Anonymous Coward]

My my, how you liberals love to make stuff up... did you know that Bill Clinton once raped someone in Central Park?

Free dessicants: Shoe store.

[Futurepower(R)]

You can get free dessicants in a shoe store. There is a small package of silica gel in every box of shoes. Friendly shoe salespeople will be glad to give them to you, since they are normally thrown away.

Putting CDs in a refigerator will work if you put them inside two plastic zipper lock freezer bags, or inside a heavy plastic container. However, use great care when you take them out. Let the entire container warm to room temperature before you open the container. Otherwise the cold plastic will cause moisture condensation.

Re:Free dessicants: Shoe store.

[gordguide]

Although this is just a bit beyond free, you might find it worthwhile to go to a hobby store (craft store) and buy a box of silica gel. It's cheap (less than $5) and there's enough in one box to equal about a thousand of the little packages.

Keep away from children and your dog. It can cause major problems if the eat it. Any air-permeable container is fine; for example a film container with a few holes punched in it. If you or someone you know can sew, then little bags can be sewn up. Throw one in with every "bag" of stuff you want to keep dry.

Silica gel is re-useable; it will go brownish when it no longer can absorb any more moisture. Pop it into the oven at moderately warm temperature for a bit (say, 140F at 20 minutes) and it will change back to it's original color and work just fine again. That works for the little packages too.

Re:Free dessicants: Shoe store.

[Reziac]

Completely OT, but re those little bags of gel... fun things to do with your college roommate who has had just a bit too much to drink the night before: toss one into the toilet, where it will sizzle most alarmingly. (This works even better if you somehow got said roommate to drink beet juice the night before. :)

Pens for labeling CDs

[lhouk281]

For those who haven't already seen them, most computer and office supply stores sell markers that are specifically designed for writing on CDs. The last ones I bought were "Smart and Friendly CD Speed Markers", and came in a pack with four different colors.

CD-safe markers. R disks permanent. RWs wear.

[Futurepower(R)]

More quotes:

"Many vendors sell CD-safe markers, and they vary in ink solution. They should not contain any solvents harmful to CDs or DVDs but should have a permanent quality. For risk-free labeling of any disc, it is best to mark the clear inner hub or the so-called mirror band of the disc, where there are no data (see Figure 12)."

"R discs: In theory, R discs should have a limited number of read times (several thousand) because of the cumulative effect on the data layer from the laser light. As with ROM discs, the polycarbonate may also eventually be affected, but there is no recorded evidence of ill effects of laser light, so such effects are deemed negligible.

"RW discs: RW discs, unlike the other types, can "wear-out." CD-RW and DVD-RW discs should last for about 1,000 rewrites, and DVD-RAM discs, 100,000 times, before the rewriting capability is lost. The reading functionality of the disc should continue for a limited number of read times after each writing. While the maximum number of read times possible after writing is unknown, it may become fewer after each successive writing."

Remember to put the little silica gel bags inside.

[Futurepower(R)]

I should have mentioned: Using TWO zipper lock FREEZER bags, not the thinner ones, or plastic containers will only work if you put the little silica gel bags inside.

I've stored vitamins this way for years. Multi-vitamins tend to be extremely sensitive to moisture, and degrade much more easily than CDs. Vitamins tend to show spots if they have been exposed to too much moisture.

Re: solvents

[TeknoHog]

Yes, Sharpies are solvent-based. Look for water-based inks.

I thought water is also a solvent? The article should make it clear which solvents are bad; though it is hinted that alcohol is better than aromatic solvents (which usually means xylene or toluene).

Hard copy is still the best backup...

[gooman]

That's why I print everything!
Ooh, just look at all of those zeros and ones.

Obvious?

[w3weasel]

Wow, that was some helpful reading!

In Other News:Grass is green, rain is wet, and people will find a way to appear stupid despite the level of their intellect.

Re: solvents

[cagle_.25]

I had the same reaction about water being a solvent. So, I went and checked the larger article to find out what they meant. Essentially, anything hydrogen-bonded is O.K.: water, alcohols of various sorts, while anything non-polar, like toluene or xylene is not. That means no:

Sharpies

White-Out

Permanent Markers, unless there happens to be a water-based permanent marker out there.
That's a real bummer, considering that I'd rather not put a label on a CD that will later smudge or bleed.
For what it's worth, I've been using Sharpies on my CD-RWs with no apparent problems. The larger article makes it clear that prolonged contact with the solvent is the real issue. So if you write on the CD with a Sharpie and then wave it around for a minute, the solvent will evaporate, leaving the ink behind. So that should be OK ... But IANACDExpert.

Media capacity follows the standard

[way2trivial]

weren't your jaz cassettes larger capacity than your CDR?

DVD's from Libraries

[felix9x]

I take out DVD's from library often.

Almost 90% have finger smudges on them. A cotton ball and some isopropyl does the job well.

At least one time some librarian wrote the libraries branch initials in black perminent marker on the data side of the disk. I thought it would be easy to wipe off -- not so. I took 20 minutes of rubbing with alchohol probably one molecule at a time to get it off.

Re: solvents

[Anonymous Coward]

The recommendations specifically state that alcohol can be used to clean a CD. Wouldn't this also sanction the use of alcohol-based labeling pens?

There's a little inconsistency here.

Haven't this been already reported ?

[ongeboren]

.. or is it just that /. is too late again?

Re:Yeah, but...

[Anonymous Coward]

What Weapons of Mass Destruction? Been looking for a year and the very man doing the looking quits and tells everyone there arn't any!

What a fucking joke. You've been lied to and you love it!

Using Happy Fun Disk

[Genda]

In an attempt to insure the best results with your removable storage media. We have collected a few suggestions. We hope that you find this information as valuable as we have, and realize that the only way to have certainty in keeping your data pristine, is to put it someplace that nature and fools with sharp objects can't get to it. So without further delay, the helpful rules;

• Warning: Pregnant women, the elderly, and children should avoid prolonged exposure to Happy Fun Disk.
• Caution: Happy Fun Disk may suddenly accelerate to dangerous speeds.
• Happy Fun Disk contains a liquid core, which if exposed due to rupture should not be touched, inhaled, or looked at.
• Do not use Happy Fun Disk on concrete.
• Discontinue use of Happy Fun Disk if any of the following occurs:
• Itching
• Vertigo
• Dizziness
• Tingling in extremities
• Loss of balance or coordination
• Slurred speech
• Temporary blindness
• Profuse Sweating, or
• Heart palpitations
• If Happy Fun Disk begins to smoke, get away immediately. Seek shelter and cover head.
• Happy Fun Disk may stick to certain types of skin.
• When not in use, Happy Fun Disk should be returned to its special container and kept under refrigeration.
• Failure to do so relieves the makers of Happy Fun Disk, Wacky Products Incorporated, and its parent company, Global Chemical Unlimited, of any and all liability.
• Ingredients of Happy Fun Disk include an unknown glowing substance which fell to Earth, presumably from outer space.
• Happy Fun Disk has been shipped to our troops in Saudi Arabia and is also being dropped by our warplanes on Iraq.
• Do not taunt Happy Fun Disk.
• Happy Fun Disk comes with a lifetime guarantee.

Happy Fun Disk! Accept no substitutes!

Has anybody tested how long data can remain in a Bass-O-Matic?

Genda Bendte

-- The disk goes whrrrrr, the cow goes moooooo...

Make copies!

[primebase]

The best preservation for digital media is to not count on the media being reliable in the very-long-term. Instead, you should invest the time and effort into making scheduled, verified copies of the media well before the predicted life of the media.

Of course, you need to not clean your CDs/DVDs with a Brillo pad in between times, and generally take care of them. But for real permanent retention, nothing's better than a fresh copy.

BTW, this copy doesn't even have to be on the same media standard -- sometimes its a good thing to revv that up as well. Remember that British Laserdisc archive they had all that trouble getting the data off of a while back when the players became obsolete?

probably because of this...

[p51d007]

For the same reason we have so many warning labels on everything you touch or do... PRODUCT LIABILITY LAWYERS LOL In this country (USA), anymore, we are not responsible for anything you do, it's always someone elses fault. Trip on your shoelaces because you didn't tie them? Sue the manufacturer of the shoes, laces. Drink too much in a bar, get behind the wheel of a car and kill someone? Sue the bar, the manufacturer of the car, the alcohol company, and anyone else you can think of. Stupidity is rewarded every day....lawsuits.

Gold?

[Leomania]

On the one-page summary they recommended using media with a gold reflective layer. My pre-coffee brain (which knows better when there's not too much blood in my caffeine stream) was thinking there was some high-end media that used real gold for the reflective layer. I don't think my $9.99/100 are gonna have any of that...

But I haven't seen any of the golden-colored layer media for a long time. Does anyone actually even make them now?

- Leo

Re:Gold?

[gordguide]

In answer to your first question; yes it's "real gold" (fake gold, whatever that is, wouldn't have the properties that make gold an appropriate medium for archival purposes).

Of course you're assuming it's a lot of gold, and therefore should cost like gold jewelry. It is a very thin layer, and costs little; it just costs a bit more than a very thin layer of silver or aluminum. You might be getting, say, a dollar's worth (probably much less).

An extra dime or dollar a disk is too much for Wall-Mart's buyers to swallow; you won't see them there.

Resellers whose customers include photographers, research, libraries, content creators, and certain corporate users will stock it.

Re:You fuck nut!

[cubic6]

Funny can also be a noun, as in "I made a funny." That usage makes just as much sense as your stupid example. Of course, I don't really think that's what he/she meant, but I feel the need to stick up for people who are abused by grammer nazis. I know it's a common mistake, but you don't need to be an asshole about it. The other thing to consider is that some people on this forum aren't native English speakers, so it's quite cruel to make fun of somebody who has only learned enough of the language to get their point across. Besides, you did understand what they said, so it isn't even that big of a deal. People make mistakes. Get over it.

Re:Looks like CD storage racks got it wrong then..

[Simonetta]

Shouldn't this study have been funded by the RIAA since their entire business model depends on the long term storage of CDs, either in warehouses, record stores, or homes?

Why should the taxpayers pay for this?

Plus the RIAA could say that the money that they have **extorted** ahem - collected - from 'pirates' has been going to research the greater public good of legitimate music CD buyers.

Maybe the RIAA really is run by morons if they can't see that a positive public relations opportunity such as a CD preservation study would help them after all the bad publicity that they generate for themselves.

We so expect them to be as slick as political consultants so that when they show themselves to be in reality just as mean, slow, and stupid as we claim that they are; we're all just a little let down.

Heh...might want to check your own...

[tit0.c]

Its grammAr not grammer...

Re:Heh...might want to check your own...

[Anonymous Coward]

I meant to do that.

Re:Looks like CD storage racks got it wrong then..

[Hatta]

I don't follow. If I store a CD on a flat surface, what's going to make it become anything but flat? At least any forces it experiences will be symetrically distributed about the axis. But if it's stored vertically, it's experiencing greater pressures on the bottom edge than the top edge. I can see how this could cause problems over time.

Re:You fuck nut!

[Gilmoure]

In the future, I'll make sure to use Sarcasm tags, in an effort to help keep panties' wadding to a minimum. Especially when replying to valued and important posts.

You've never worked in Tech Support Have You?

[Sleetan]

I had to work on one computer where the complaint was, "The CD drive isn't working."

Once I finally got the cd drive open I discovered they were using a disk with what looked like guaze dipped in glue for a label.

You get the point. I'm considering printing this guide out and handing it to clients.

It DOESN'T answer the adhesive label question...

[dpbsmith]

...all it says about adhesive labels is that they shouldn't be applied for disks that are to be kept for more than five years because it might "delaminate" (start to peel off) and interfere with disk drive operation, and because any attempt to remove such a label will likely result in an imbalanced disk.

The recent reports concern CD-R's that are less than five years old, have nothing visibly wrong with them, but cannot be read.

No, Sharpies are NOT safe (aaargh!)

[monkeyfamily]

NIST tells us not to use anything solvent-based, and Sharpies are solvent-based markers. In fact, the Sharpie Materials Safety Data Sheet (pdf) tells us they contain 3 different solvents - a propanol, a butanol, and an alcohol. One Eric Teel of Jefferson public radio (in Oregon) wrote the manufacturer of Sharpies and they said there could be problems.

Damn, and I've got hundreds of CD-Rs written on with Sharpies. I hope they last till I get around to buying a DVD burner and transferring the data.

Re:No, Sharpies are NOT safe (aaargh!)

[n6mod]

They aren't safe, but they aren't the worst thing in the world either. The NIST guide indicates that alcohol-based pens are less harmful than aromatic-based pens, and all three of the solvents listed on the Sharpie MSDS are alcohols. The last one, diacetone alcohol, is a little worrisome, but as acetone is itself highly volatile, I'm not too worried.

Looks like water-based felt pen or printing on printable-surface DVD-R is the right answer long term, but I think your CD-Rs will last a couple more years.

doppler00

[Doppler00]

How about backing up multiple DVD's to an H-DVDRW disk (when they are released?). It would be nice to have a backup of multi-disk movies on one disk. Of course, there is the encryption problem...

Mylar punch tape, baby

[John Jorsett]

By far the toughest storage medium I ever encountered was mylar punch tape. That stuff can stand up to anything but fire. I'm a strong strapping lad and I can barely deform even a single strip (and you could still reconstruct the bits from it if you had to). It's decidedly low-density storage by today's standards, but short of carving your bits on rocks or etching them onto gold plates, I don't think you'd find anything better.

Re:Mylar punch tape, baby

[ManxStef]

...but short of carving your bits on rocks or etching them onto gold plates, I don't think you'd find anything better.

Yup, etching human-readable data into metal and distributing it around the planet is about as good as you can get at the moment :)

See the Rosetta Project that uses Norsam Technologies HD-Rosetta is a very interesting real-world example. Reading the Los Alamos National Labs tests of HD-Rosetta gives some amazing results: 300 deg. C for 65 hours or exposures to saltwater/tap water/a simulated marine air environment for 15 weeks did not affect readability of the text!

My favourite bit is where they say:

However, these results cannot be extrapolated to very long times because chemical changes in the environment that may take place with time were not taken into account.

If you're covering issues like that you're talking about a long time (thousands of years?)!

Re:Looks like CD storage racks got it wrong then..

[CaptBubba]

The RIAA's buisness would be much better if people didn't know how to store their media.

They don't want you to keep cds for a long time, they'd be perfectly happy if everyone scratched up their cds and had to buy new ones every couple years. Much of their buisness comes from people buying stuff they already have bought in the past, it doesn't matter if it is on an old format like tape or if they just destryed the original.

I think the CD-RW boom has hurt the music industry in this way. Now, you can make a perfect backup to use in your car, or while exercising, or at work. It costs ten cents so you don't have to worry about scratching them. Ever since I had a few of my cds stolen, I use copies for most everything. Short of a fire in my room, the originals are safe.

Re:Looks like CD storage racks got it wrong then..

[Reziac]

I doubt that the rack manufacturers knew or cared; they were just creating convenient storage form factors, without regard to whether that was the best storage position or not.

Re:Looks like CD storage racks got it wrong then..

[Reziac]

But inside its case, the CD is typically only supported in the middle. And a bow that's not visible to the eye might be plenty big enough to throw off a laser's tracking.

It's probably like with vinyl LPs, where no position is perfect, but over the long haul they're best off standing on edge, packed sufficiently to give one another support, but not so tight that they pressure-warp one another.

bend over hoe, cuz i got something to give ya

[Anonymous Coward]

i'll fuck the dumb right out of ya

Re:Looks like CD storage racks got it wrong then..

[guardia]

No, it is OK to store pressed CDs and DVDs in any position you like AFAIK. They are only talking about CD-R, DVD-R, and the likes.

Wrong approach

[El]

This is digital information. Eventually the media is going to fail -- guaranteed. Best approach is to make 100 copies of it at 100 different locations, then make new copies of the copies every year. With massive redundancy so cheap, who cares who unreliably a single copy is? This is one of the as yet untapped possibilities offered by the internet -- to be a perpetual archive for the information people consider important enough to provide the resources to make massively redundant copies.

Re:how I'm doing?

[claudebbg]

Hi, when I was using Windows, I was using Cygwin on a PC to do basic scripting stuff between the Mac & the PC but no rsync. Perhaps you can try using rsync with no dates (-I aka --ignore-times, and -t aka --times to avoid checking and updating times).
More generally, I clearly avoided the conflict management between different sources (I just move datas), but carefully checked rsync options. What I did is

• defining clear home directories (quite easy as MacOsX defines most of them, but I also added some of my own).
• I then duplicated this list of directories in 3 sets: real home (~) for live files, "Shared" for all that stuff I like to have with me but don't really update so often and "Archive" for the cold files I'll certainly use one day.
• I linked (ln -s) those places (i.e. xxx/~/Movies/SharedMovies "is" xxx/Shared/SharedMovies and xxx/~/Movies/SharedMovies/ArchiveMovies is xxx/Archive/ArchiveMovies)
• I wrote some simple rsync scripts to sync one computer to another and one drive to another (not exactly the same options; not the same paths to sync)
• So I can update the laptop from the desktop when I go outside (or just want to work from the couch) and resync the opposite way when I'm back to the desktop. As it's ssh I can do it from one or another computer.
• I've decided to keep "~" and "Shared" on the 2 computers, and to keep "Archive" only on the desktop and the external disk (which also keeps some DVD I plan to watch (the disk is far more silent than the combo internal drive). Of course, one can triple the files to be sure, it(s better.
• I also do standard backups (cron triggered to launch cleanup and backup scripts every 7 days or the next time I turn the computer on) for critical files and tools, encrypted and saved (I usually keep last week and last 2 months, I don't need to go back in the past more than that and I'd also notice a problem before)

My options (machine to machine) are

• -verbose (I filter the unused things but I like to see what happens)
• --recursive --links --one-file-system
• --partial --compress (seems to be better with low bandwidth link like 802.11b)
• --perms --owner --group --times (both unix)
• -e ssh
• --delete (only one direction!)
• --backup (I prefer to clean after but to be able to handle conflicts when I modify something on both places)
• --suffix="~" --exclude "*~" --exclude $'Icon\r'

I hope it'll help you on defining a method that fits your needs.

Ok, that explains what she's doing on slashdot ...

[Anonymous Coward]

If I wanted to see anything that might be in Playboy I could just go take a bath,

Thanks for clarifying that you're not a real 'chick', but a substantially digitally altered one. Now I understand what you're doing on slashdot :-)

P.S. Be careful not to get all wrinkly if you spend too much time in the water -- that happens to real people too.

Ahem...

[fm6]

I say "watter ... other solvents".

For caddies, DVD may be the way to go

[Ranazar]

Around the office, we have some old CD-ROMs for IBM RS/6000 machines which require caddies. Well, we recently purchased some new DVD writers from IBM, and damned if they didn't use caddies as well.

The DVD caddies are slightly different from the ones used in the old CD-ROMs (and the two are not interchangeable), but they're close enough to make it obvious that IBM is resurrecting an old concept for the future.

In typical fashion, though, the DVD writers from IBM will only accept DVDs in a caddy, while the new servers we got from them (with DVD drives), will only accept DVDs without a caddy -- and of course, the DVDs that IBM sell come in a caddy that cannot be opened and closed (like the old CD-ROM cases). I had to go to Future Shop to get an openable case!

Re: solvents

[stickb0y]

Essentially, anything hydrogen-bonded is O.K.: water, alcohols of various sorts

Sharpies use alcohol-based inks.

The CD-R FAQ indicates that Sharpies should be okay.

I Found This Topic Interesting

[Master of Transhuman]

because a week or so ago I had a long argument with someone on one of the Linux newsgroups about backing up to CD and whether CD media was reliable.

I advocated backup to spare hard disk and pointed out that some sysadmins were starting to rsync to offsite hard drives as a primary backup method. Benefits were cost vrs tape, speed vrs tape, accessibility vrs tape, and reliability vrs tape, etc.

The other fellow argued that for home use CDs were much better because HE never had a CD read or write error in six years. I on the other hand have had write errors on my drive when burning faster than 4X (it's a 16x12x40 and I use media rated up to 52X). I granted him that there might be a problem with my drive. But I still don't trust CDs for critical data backups - I make multiple copies of that data, single copies of data that isn't critical (babe pictures from the Net, e.g.).

This article reinforces my view. CDs and DVDs are good for backup, but for critical data and for long-term archival storage, they are NOT as good as a hard disk which is used only for backup and is protected from abuse. You might have the odd stiction problem with a hard drive that's been stored a long time, but the data itself is likely to be recoverable on the platter AFAIK.

I'm not that concerned with long-term archival storage anyway (although the Fred Langa article that suggested two years was "long-term" is unnerving).

For home use, the cost per gig of hard drives today, while still more than CD's (but not by much since you need two CD's to backup a gig - compression increases the risk of unreadable data if you want to advocate it - unless you compress each individual file first, of course), is still a very cheap way to backup data at $1 or less per gig. Especially for data which changes over time and doesn't need to be archivally stored - just replaced whenever it changes. Offsite storage can either be done by CD/DVD or by a third disk or by mirroring offsite (some companies offer this service).

I'm not against CDs or DVDs for backup but the risks and benefits vrs dedicated backup hard drives needs to be considered carefully. A good backup strategy for home use will use both CDs/DVDs and/or tape AND hard disks. For business purposes, a good strategy will use both tapes and rysnced backup hard drives.

Re: solvents

[some guy I know]

That means no [...] White-Out

Damn!
And I've been using White-Out all this time to erase my CD/RWs (faster than having the drive do it).
No wonder I would sometimes have problems reusing my CD/RWs.

Re:Looks like CD storage racks got it wrong then..

[Anonymous Coward]

You're an idiot. Seriously, every post you've made on this topic shows how stupid you are. I mean look at
this post for example.

fucknuckle

Re: solvents

[cagle_.25]

right you are...I should have checked the MSDS first instead of going by smell. Thanks, Jeff Cagle

avoiding tape across CDs...

[Wilk4]

As a funny true story, a small team of us got gold release candidate build cd's once from a software company a year or so ago... we'd been helping with beta testing and they wanted to send the release candidate out on CD instead of download...

Anyway, whoever sent them out made nice CD-R's on the gold disks, then scotch-taped them to cardboard sheets that went into the envelopes. The tape was on the data side! So, no matter how careful you were, when you tried to take the tape off, it peeled large amounts of the gold foil right off the disk.

Needless to say, they had to mail out a new set of disks to the whole group...

Moral of the story, make sure your secretary, mailing clerk, whatever is taught how to handle store and send CDs, not just your techies...

long-term storage and extended-term storage

[neves]

What's the difference between long-term storage and extended-term storage?