Patent ID: 7743031

Claim:
A non-transitory computer readable medium for a data storage device encoded with a snapshot tree structure and code for managing the snapshot tree structure to provide point-in-time backups of a base volume, wherein: the snapshot tree structure comprises: a first branch, comprising: the base volume storing a current user data; a first read-only snapshot descending from the base volume, the first read-only snapshot being created at a first time, the first read-only snapshot storing a first data of the base volume at the first time before the first data is modified in the base volume; and a second read-only snapshot descending from the first read-only snapshot, the second read-only snapshot being created at a second time earlier than the first time, the second read-only snapshot storing a second data of the base volume at the second time before the second data is modified in the base volume; and the code comprises instructions to retrieve data from the snapshot tree structure and transmitting the retrieved data to a host device.