Patent ID: 7802134

Claim:
A method for restoring content of a plurality of data blocks to non-volatile storage as the content existed at a particular instant in time, the method comprising: an act of accessing a last backup representing the most recent backup of the plurality of data blocks prior to the particular instant in time; an act of writing the content of each data block represented in the last backup to a corresponding position in the non-volatile storage; an act of accessing a second-to-last backup representing the second most recent backup of at least a portion of the plurality of data blocks prior to the particular instant in time; and after the act of writing the content of each data block represented in the last backup, an act of performing a non-overlapping write of the second-to-last backup by performing the following: for each of at least one data block that is represented in the second-to-last backup, but is not represented in the last backup, an act of writing the data block of the second-to-last backup to the non-volatile storage; and for each of at least one data block that is represented in the second-to-last backup, and is also represented in the last backup, an act of refraining from writing the data block of the second-to-last backup.