Slashdot is powered by your submissions, so send in your scoop

 


Forgot your password?
Close
typodupeerror
×
Data Storage

Guide to Digital Preservation from NIST 190

Posted by michael from the jesus-saves dept.
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."
This discussion has been archived. No new comments can be posted.

Guide to Digital Preservation from NIST More

Guide to Digital Preservation from NIST

Comments Filter:
  • I wonder if post it notes are bad?

  • Felt markers for labeling CDs (Score:5, Funny)

    by sidney ( 95068 ) on Saturday January 24, 2004 @08:38AM (#8074385) Homepage
    Use a black felt pen. If you do it right you get to label the CD and defeat copy protection [wired.com] at the same time
    • 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?
      • 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.

        • NIST tells us not to use anything solvent-based, and Sharpies are solvent-based markers. In fact, the Sharpie Materials Safety Data Sheet [sharpie.com] (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 [findlaw.com].

          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.

          • 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.

        • Ahem... (Score:2)

          by fm6 ( 162816 )
          I say "watter ... other solvents".

  • I dont trust any format. (Score:5, Insightful)

    by MrRTFM ( 740877 ) on Saturday January 24, 2004 @08:39AM (#8074389) Journal
    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.

    • 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 ;))
      • Punch cards don't corrupt

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

    • Best for floppies... (Score:1, Funny)

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

      The solution... VIAGRA!
    • 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.
    • 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
      • 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 backu
    • 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

      • 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.
        • 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 possib

        • 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

      • 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. :-)
        • 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 i
    • What do you do about disaster recovery?

  • When I was young... (Score:5, Funny)

    by cwernli ( 18353 ) on Saturday January 24, 2004 @08:42AM (#8074395) Homepage

    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.

    • 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!
      • 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 (Score:5, Interesting)

    by formalS ( 712471 ) on Saturday January 24, 2004 @08:43AM (#8074400)
    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.
    • .50 Caliber ammo boxes seem to work best, as far as size. You can conviently fit two CD case holders inside.
    • 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 c
  • How does the use of a black felt marker [slashdot.org] affect CD longevity?

  • Looks like CD storage racks got it wrong then... (Score:4, Interesting)

    by rklrkl ( 554527 ) on Saturday January 24, 2004 @08:57AM (#8074427) Homepage
    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?

    • Re:Looks like CD storage racks got it wrong then.. (Score:5, Funny)

      by Teddy Beartuzzi ( 727169 ) on Saturday January 24, 2004 @09:04AM (#8074449) Journal
      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?

    • Re:Looks like CD storage racks got it wrong then.. (Score:5, Informative)

      by mobby_6kl ( 668092 ) on Saturday January 24, 2004 @09:22AM (#8074499)
      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.
      • 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.
      • 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.
        • 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.

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

    • 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.

  • Digital Preservation (Score:5, Funny)

    by SteveTheRed ( 244567 ) on Saturday January 24, 2004 @08:58AM (#8074432) Homepage
    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... (Score:4, Funny)

    by devnullish ( 743715 ) on Saturday January 24, 2004 @09:00AM (#8074436)
    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!
    • 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.

  • Guide to Analog Preservation from LoC (Score:5, Informative)

    by O ( 90420 ) on Saturday January 24, 2004 @09:03AM (#8074443)
    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! [loc.gov]

  • DRM (Score:5, Insightful)

    by wrmrxxx ( 696969 ) on Saturday January 24, 2004 @09:03AM (#8074444)
    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.

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

  • is CD still a backup media? (Score:4, Interesting)

    by claudebbg ( 547985 ) on Saturday January 24, 2004 @09:07AM (#8074458) Homepage
    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?
    • 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 [sourceforge.net] so that even if the media gets badly scratched, you'll have decent odds of being able to repair the damage. (And
    • 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

    • 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

  • what are we made of?! (Score:5, Funny)

    by Anonymous Coward on Saturday January 24, 2004 @09:09AM (#8074463)
    "Do not: ...
    8. Expose recordable discs to prolonged sunlight..."

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

  • Gee, NIST forgot a lot of things (Score:3, Funny)

    by Rosco P. Coltrane ( 209368 ) on Saturday January 24, 2004 @09:09AM (#8074464)
    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

  • Timely article... (Score:5, Interesting)

    by Jin Wicked ( 317953 ) on Saturday January 24, 2004 @09:10AM (#8074469) Homepage Journal

    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...?

    • 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
    • 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.
    • --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.
      • --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.
    • 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 s
  • 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.
    • 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.

    • weren't your jaz cassettes larger capacity than your CDR?
    • "...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

  • Amazing. (Score:4, Funny)

    by DarkHelmet ( 120004 ) * <mark&seventhcycle,net> on Saturday January 24, 2004 @10:01AM (#8074590) Homepage

    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.

    • 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.

  • they forgot the most important one... (Score:4, Funny)

    by scatterbrained ( 144748 ) on Saturday January 24, 2004 @10:04AM (#8074600) Journal
    don't forget to protect against nature's most
    destructive force - 3 year old boys on a sugar
    buzz.

  • Heat and Humidity (Score:4, Interesting)

    by Pedrito ( 94783 ) on Saturday January 24, 2004 @10:05AM (#8074602)
    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 (Score:3, Informative)

      by dlamming ( 152302 )
      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.

      • 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.


    • 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 m

      • 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.
      • 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 ever
        • 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. :)

    • 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

  • Water-based markers are recommended. (Score:3, Interesting)

    by Futurepower(R) ( 558542 ) on Saturday January 24, 2004 @10:10AM (#8074613) Homepage

    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."

    • 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 wit

  • Misleading (Score:4, Informative)

    by Transcendent ( 204992 ) on Saturday January 24, 2004 @10:17AM (#8074628)
    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.

  • Pens for labeling CDs (Score:2, Informative)

    by lhouk281 ( 604066 )
    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.
  • 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 -- some
  • ...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.
  • 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 (Score:4, Interesting)

    by John Jorsett ( 171560 ) on Saturday January 24, 2004 @02:58PM (#8076031)
    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.

  • Wrong approach (Score:3, Interesting)

    by El ( 94934 ) on Saturday January 24, 2004 @05:16PM (#8076918)
    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.
  • 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 si

Slashdot Top Deals

The rule on staying alive as a program manager is to give 'em a number or give 'em a date, but never give 'em both at once.

Close