Fault-tolerance in very large archival systems

An interesting prospective application for computer systems is really-long-term archival storage of information, as has been traditionally performed by libraries, using books and serials. As costs of large-scale storage devices fall, librarians periodically reevaluate the question of whether or not to commit to digital storage any of the materials in their care. In the past there have been several concerns, but it has not been necessary to think very hard about them because the dominating concern has been that the cost of storage made the idea unworkable.