You brought a digital camera along on the family vacation and took a ton of snapshots. Now how can you keep those pictures around for your kids to enjoy in 20 years? In 50 years, will your grandchildren's computers be able to read the data?
In a computing culture where five-year-old hardware is antique beyond belief, it's easy to forget about the possibility that we might need to rely on individual CDs or Zip disks decades into the future. But it's an issue that computer users will have to face as more and more journals, letters, music collections and photo albums exist solely as computer files.
The guidelines for choosing computer media would seem fairly simple. "The three things to look for are capacity, performance and long-term reliability," said Jeff Ash, vice president of marketing in Fujifilm's computer products division. But the reliability issue -- what techies call "data permanence" -- depends on the quality of the media and its storage conditions. In other words, it's hard to tell.
Standard 3 1/2-inch floppy disks should last about a decade, according to Fuji. Zip disks should work for about 30 years, and quality CD-Rs have a life expectancy of 75 to 100 years. As for CD-RWs, the answer isn't so clear; some experts say there's no difference between CD-R and CD-RW shelf life, but Fuji's Web site, for instance, cites a 30-year lifespan for RW disks.
Optical media such as CD-R or CD-RW "are better for archival storage, definitely," said Scott Gaidano, president of Drivesavers Data Recovery, a Novato, Calif., company that recovers lost data from computer media. "CD-Rs in my opinion are your best shot right now."
These shelf lives are only estimates -- most computer media haven't been around long enough to know for sure. Manufacturers use environmental testing chambers to simulate the aging process and gauge the effects of temperature, humidity and other factors.
It's important, particularly with CD-R, to choose media from reputable brand-name companies. Super-inexpensive CD-Rs may only last a few years and, in some cases, have failed after just a few months. The problem is delamination -- a breakdown of the adhesives that bind the disk.
"If the proper adhesives are not used in the manufacturing process, CD-Rs tend to delaminate in a real short period of time," Gaidano said. "Every company has multiple lines of products -- buy the premium quality. I wouldn't buy from weird companies."
Magneto-optical disks, popular in Japan but less well known in the United States, use a laser to etch data onto more robust, delamination-proof disks, then read it back magnetically. But almost no home computers include MO drives, which cost $250 to $310 for consumer-level models and use comparatively pricey disks, at about $30 for 640 megabytes.
Even if the information on your removable media remains intact, it will be useless if hardware to read that disk isn't available down the road. Companies can stop making particular models of drives, or can go out of business outright.
For example, in 1998, Syquest, once the leading manufacturer of magnetic removable-media drives, filed for bankruptcy, creating headaches for users who needed repairs or additional media. Just last month, Longmont, Colo.-based OnStream, which had made a line of well-liked tape drives, shuttered its doors.
To prevent committing priceless data to an obsolete medium, it's wise to choose a storage option that doesn't lock you in to one company -- for instance, CD-R or other optical disks. Another insurance policy is to make multiple backups on different kinds of disks. Saving those honeymoon pictures on both CD-ROM and Zip offers twice the chance that the data will stay readable.
In the short term, no storage decision is final -- if something better comes along, you can copy the data to that new medium. And in the long run, it doesn't matter. "The way technology is moving, all of these will be extremely obsolete 30 years from now," Drivesavers' Gaidano said. Still, he's hopeful -- you can still buy a phonograph to play 78-rpm records.
How the media is stored will affect its life expectancy. Fujifilm's Ash offered a list of suggestions: Like wine, store media in a cool, dry, dark location. But try to keep disks free of dust as well. And keep magnetic media -- in home use, floppies and Zip disks -- away from magnets and other sources of magnetic fields, like speakers and electric motors.
CD-Rs need to be stored and handled with extra care -- be vigilant about not scratching either side of the disk. "CD-Rs are far less tolerant of environmental conditions than pressed CDs, and should be treated with greater care," cautions Andy McFadden's CD-Recordable FAQ (www.cdrfaq.org). It notes that the easiest way to make a CD-R unusable is to scratch the label side of the disk.
Think about which format you store your files in, too. "Make sure the documents are stored in a non-proprietary format, so that there will always be software around to display the documents in eye-readable format," said Tom Wayman, senior technologist at LaserFiche Document Imaging, a Torrance, Calif. firm that electronically archives paper documents. For images, use JPEG or TIFF. For text, plain ASCII is best; HTML will do as well, but funky designs that look great on today's browsers may appear awful in future software.
Your best bet for long-term storage, however, is decidedly low-tech: paper. But remember that the weak link in a printed documents is the ink. Consumer-level color inkjet output fades faster than traditional prints on photographic paper, especially when exposed to light. Print your hard copies on acid-free paper, park them in an acid-free environment such as plastic storage sleeves, and they can outlast a CD-R's theoretical 100-year lifetime -- and will require no specialized hardware to view in the year 2102 either.