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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."
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.
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?
- 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
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?
ClaudeBBG
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...?
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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?
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.
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."
Sharpies
White-Out
Permanent Markers, unless there happens to be a water-based permanent marker out there. ... But IANACDExpert.
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
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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?
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.
Gamingmuseum.com: Give your 3D accelerator a rest.
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.
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.
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