Patent 7188230 was granted and assigned to Hitachi on March, 2007 by the United States Patent and Trademark Office.
A method for assuring the integrity of stored data in a storage system is provided. At a specified time at which further writes to a desired portion of the stored data are to be precluded, a hash value is calculated for the desired portion of stored data. At a later time, retrieval of the stored data is performed and the hash value recalculated. A comparison of the former and present hash values reveals whether the data has remained unchanged.