File system coherency of a file system, particularly for system blocks, may be maintained by (i) duplicating and verifying the (system) blocks, (ii) writing (system) blocks as a sequence of atomic commands so that at any given time, there is a valid (system) block on a physical storage device, and/or...http://www.google.de/patents/US7464125?utm_source=gb-gplus-sharePatent US7464125 - Checking the validity of blocks and backup duplicates of blocks during block reads
