Patent ID: 7428621

Claim:
A method of managing content units on a storage system that stores the content units, the method comprising acts of: in response to a request to identify the content units that were stored on the storage system at a specified time, determining which of the content units stored on the storage system when the request was received were stored on the storage system at the specified time; and determining which content units deleted from the storage system were stored on the storage system at the specified time by examining reflections of deleted content units, each reflection identifying at least one corresponding deleted content unit without storing all of the content of the deleted content unit or identifying a location at which all of the content of the deleted content unit is stored, and including information that identifies a time at which the at least one corresponding deleted content unit was deleted from the storage system, wherein each of the reflections includes a first timestamp that indicates the time its corresponding deleted content unit was stored on the storage system and a second timestamp that indicates the time its corresponding deleted content unit was deleted from the storage system, and wherein the act of determining which content units deleted from the storage system were stored on the storage system at the specified time further comprises an act of determining which content units deleted from the storage system were stored on the storage system at the specified time based on the first and second timestamp of each of the plurality of reflections.