Migrate every five years." That might sound like a guideline for dysfunctional birds, but it's actually a software setting that the National Film Board of Canada uses in its digital archiving system.
"The data has to be kept for infinity, so there has to be a migration process," says Julie Dutrisac, head of research and development for the film board in Montreal, which preserves 13,000 Canadian films. "When you get into the digital domain, you are stuck migrating."
Migration, of course, means moving the material to new storage hardware, because the old hardware can't be expected to last much more than five years, or because of expected obsolescence.