Patent ID: 6073222
Filing Date: 2000-06-06
Classification: G06F

Abstract:
In a computer system including a mass storage system having a plurality of data blocks and a preservation memory, a method for accessing data as it existed in the mass storage system at a selected moment using a virtual device, comprising the steps of:establishing at the computer system a virtual device that can process requests for at least one of writing or reading data as though it were an actual data storage device;preserving an original data block as it existed in the mass storage system at the selected moment by placing the original data block in the preservation memory when a new block written to the mass storage system is to overwrite the original data block after the selected moment; andusing the virtual device to access the data as it existed at the selected moment in the mass storage system, including the steps of:accessing the preserved original data block placed in the preservation memory; andaccessing another original data block that remains in the mass storage system and that has not been overwritten since the selected moment.