A primary computer system and a backup computer system each have an associated memory. For each write request, a copy of the request is forwarded to a delay buffer and memory queue associated with the primary computer system, and a copy is forwarded to a memory queue of the backup computer system. The...http://www.google.es/patents/US6338126?utm_source=gb-gplus-sharePatente US6338126 - Crash recovery without complete remirror
