Patent ID: 7930499
Filing Date: 2011-04-19
Classification: G06F

Abstract:
1. A storage system for effecting a block-level protocol connection between a host and a data storage medium for writing data from the host to a first storage area of the data storage medium, and for writing data from the first storage area to a second storage area, the storage system comprising: means for initializing a logical unit (LUN) in the first storage area; a persistent memory storing a data representation of clean areas in the LUN which have not been written to since the initialization; a writing system for receiving data to be written from the host to a destination area in the LUN and saving said received data in a cache memory; said writing system being configured to examine said data representation of said clean areas and determine if the destination area in the LUN is a clean area based on the data representation in the persistent memory; said writing system removing, from said data representation of said clean areas in said persistent memory, an area containing the destination area when it is determined that the destination area in the LUN is a clean area; said writing system not altering said data representation in said persistent memory when it is determined that the destination area in the LUN is not a clean area; and said storage system including a read/write controller which effects reading and writing of data to and from said LUN, said read/write controller being configured to carry out said reading and writing of data to and from said LUN except when an area in said LUN which is a target of either said reading and writing of data is determined to be a clean area based on the data representation in the persistent memory.