Patent ID: 7376651

Claim:
A storage device, comprising: a plurality of disk drives; a plurality of directors, in communication with the plurality of disk drives to handle receiving and sending data for the storage device; and at least one additional director, in communication with at least one of the plurality of directors, wherein the at least one additional director includes a computer-readable storage medium that contains executable code that provides a virtual storage area having a table of pointers that point to one of: a disk storage area and a volatile memory area, wherein the virtual storage area contains no sections of data, executable code that determines which particular one of the areas contain the data in response to a request for accessing data of the virtual storage area, executable code that accesses the data on the particular one of the areas using the table of pointers, executable code that associates the disk storage area with the virtual storage area, wherein the virtual storage area represents a copy of data of the disk storage area, executable code that causes all of the pointers of the table to initially point to sections of the disk storage area when the virtual storage area is initially associated with the disk storage area, and executable code that copies data of the first section to a second section of the volatile memory area and causes a corresponding one of the pointers of the table to point to the second section in response to a write to the first section.