Suppose you spent so much on a new CD-ROM drive that the budget won't stretch for speakers, so you decide to do it on the cheap.
You rummage around in the garage and find a pair of auto speakers that you discarded when you upgraded your new car stereo. You brush off the leaves and cobwebs, trot inside and wire the speakers to the stereo amplifier, run a cord from the PC's sound card into the amp, and connect.Assuming you know enough about electronics not to electrocute yourself, the auto speakers start blaring sound effects from "Return to Zork." Thunder rumbles, streams splash, the boozehound in the mill croaks, "Want some rye? 'Course ya do." Wonderful sound quality!
After the game you resume work on the great American novel. You're almost finished with the climatic chapter - where is it? Oh, here's the floppy, right on the speaker where you left it. You pop it in and tell your word processor to call up the Trilobites chapter.
Instead of your undying prose, this message flashes on the screen: "The disk in drive A is not formatted. Do you want to format it now?"
Gone! There's nothing on the disk, not even the formatting. The Trilobites chapter has evaporated.
Speakers project magnetic fields, and magnetism is what writes and holds data on the oxide that coats the disk's vinyl base. A magnet will erase a disk and so will magnetic fields like those emanating from speakers. Although speakers packaged with multimedia kits are shielded to protect the computer from magnetism, others aren't.
Our scenario won't happen to many computer users. But eventually, something fatal to data will strike all disks: obsolescence or physical deterioration.
How to preserve digital information is one of the hottest debates on the Internet. A whole mini-archive has been created just to debate a January 1995 article in Scientific American magazine by Jeff Rothenberg of the RAND Corp., in which he advocated copying certain digital information every year.
Electronic memories fade fast. Storage on hard disks is expensive, and data can be ruined if the internal disk crashes (though specialists often can retrieve some information through special utilities). Floppies probably won't last more than a decade before magnetism, heat or moisture either erases them or damages the disk's physical structure.
Digital tape backup is one of the best ways to protect information, though even then the tape may not last more than about 20 years. Storing a digital tape or a disk at high humidity or where it's hot could cause the binder to degrade, wrote Jim Wheeler of the Association for Moving Image Archivists.
John W.C. Van Bogart of the National Media Lab responded to Scientific American by saying years of research show that magnetic tape life-expectancy can be 10 to 30 years.
And that brings up the problem that archivists generally see as most pressing: the rapid pace of technological change makes many types of media obsolete in a few years. As an analog analogy, my reel-to-reel tape recordings from the middle 1960s were unplayable for decades, until I found a tape player in an antique shop; they were superseded by eight-track tape and then 8 mm. tape casettes.
Even optical disks - that is, CDs - are perishable. The phrase "laser rot" was used to discredit the longevity of CDs. According to one note on the Internet, some "apparently stupid CD pressing plants" used caustic ink on the labels, causing the disks to deteriorate.
Joe Potts, assistant development librarian at the University of Utah's Marriott Library, said until recently the answer to deteriorating books and newspapers was to save information on microfilm. "From there that's fairly easy to copy and store," he said.
"The microfilm has a pretty long shelf life," perhaps 20 years, he said.
Shelf-life for a floppy ranges from "a few minutes to a few years." With CD-ROMs, computer information may be somewhat more permanent, "but since they're so new, nobody knows how long they're going to go.
"Part of the problem is that the formats change."
Cornell University and Xerox Corp. have launched a Commission on Preservation and Access Joint Study in Digital Preservation, which attempts to preserve data by scanning valuable papers onto a digital format. The study first tackled 535 volumes from Cornell's Mathematics Library, monographs from 1850 to 1916, many of them in poor physical condition.
After the papers were scanned at 600 dots per inch resolution, the data were transferred to CDs. Then pages were printed out on high-quality paper and bound.
"Cornell is committed to a process that will continually `refresh' our digital library so that each volume is copied every four years," says a report on the project, which can be read on the Internet. Refreshing copies the digital information onto a fresh CD not likely to deteriorate in the next four years.
Technological obsolescence can be overcome by "refreshing" whenever you change media. When you upgrade from 51/4-inch drives to 31/2-inch disks, copy all your old data onto the microfloppies. When CD scanners are affordable, copy your microfloppies onto optical disks.
Between technological revolutions, every few years take the time to refresh within the same kind of media, using new disks. And keep them away from magnets.