Patent ID: 8799337

Claim:
A computer-readable storage medium having instructions encoded thereon that, when executed in a computing device that provides a capability whereby input is received to restore the computing device to a state in which the computing device existed at a previous point in time, perform a method comprising: providing a file system managed by an operating system of the system, the file system comprising a plurality of file system portions including a first file system portion storing information relating to the operating system, a second file system portion storing information relating to applications on the system, and a third file system portion storing information relating to user data on the computing device; storing the file system portions on respective separate first, second, and third virtual hard disks, each virtual hard disk reflecting an original state of the corresponding file system portion, the first virtual hard disk storing the first file system portion and not the second and third file system portions, the second virtual hard disk storing the second file system portion and not the first and not the third file system portions, the third virtual hard disk storing the third file system portion and not the first file system portion and not the second file system portion; for each of the file system portions, storing changes made thereto over time on a respective sets of differencing virtual disks, wherein changes to the given file system portion are stored only by the set of differencing virtual disks that correspond thereto, wherein the first file system portion does not store the second file system portion and does not store the third file system portion, wherein the second file system portion does not store the first file system portion and does not store the third file system portion, and the third file system portion does not store the first file system portion and does not store the second file system portion; and receiving input to restore a given one of the file system portions to a state at a first point in time by selection of a target differencing virtual disk, for the given file system portion, that stores information as of or prior to the first point in time.