US Patent 7853762 Controlling access to non-volatile memory

Access to non-volatile memory is controlled when a first data segment is loaded in the non-volatile memory from a hard disk, a weight is calculated for the first data segment stored in the non-volatile memory based on at least one of the access frequency, the access recency, and the size of the first data segment, and the calculated weight is stored in a weight table. A removal rank is calculated for the first data segment based on at least one weight stored in the weight table, a determination is made as to whether a storage capacity of the non-volatile memory is utilized above a predetermined threshold, and a data segment is removed from the non-volatile memory based on a removal rank associated with the data segment.