Patent ID: 8051252

Claim:
A method for representing the presence of a subblock in a storage system, comprising: hashing a subblock to obtain an index hash value for the subblock; creating an array of bits using a function that inputs the index hash value for the subblock and outputs bits into the array of bits and maps the subblock to a position in the array of bits, where a bit in the array of bits is a predetermined bit value that indicates whether at least one subblock in the storage system maps to the bit position in the array of bits; selectively storing the index hash value in a subblock index located on the storage system if the subblock is absent from the storage system; selectively storing the index hash value in a subblock index entry write buffer located in memory if the subblock is absent from the storage system, where the index entry write buffer is divided into a plurality of buffer portions corresponding to a portion of the subblock index located on the storage system; and transferring the contents of the index entry write buffer to the subblock index located on the storage system using a single sequential read and write operation of the storage system.