Abstract: One embodiment of the invention is directed to providing a single instance storage capability in a content addressable computer system that stores content units in a time-based directory structure. Another embodiment is directed to managing access to content units that do not include a timestamp in their content addresses, in a time-based directory structure. A further embodiment is directed to accessing replicated content units stored on a computer, based on a time of replication. A further embodiment is directed to employing a bitmap in a time-based directory structure which may be used to indicate whether any content units stored during a specified time range are stored in the directory structure.

Abstract: A snapshot tree structure includes a base volume storing a current user data at a current time, a first read-only snapshot descending from the base volume, and a second read-only snapshot descending from the first read-only snapshot. The first read-only snapshot is created at a first time earlier than the current time. The first read-only snapshot stores a first data of the base volume at the first time before the first data is modified in the base volume. The second read-only snapshot is created at a second time earlier than the first time. The second read-only snapshot stores a second data of the base volume at the second time before the second data is modified in the base volume.

Abstract: Chunks are stored in a data store, where respective collections of chunks form respective files. An index that maps digests of chunks to pages containing information to recreate the chunks is provided, where the index is stored in persistent storage.

Abstract: A method for browsing objects on a protected volume in a continuous data protection system begins by displaying a list of top-level objects to a user who selects a top-level object to browse. A snapshot is selected from the selected top-level object and is decoded. A list of objects in the selected snapshot is displayed and the user selects an object to browse. The selected object is decoded and operations are performed on the selected object. The user can browse the protected volume by snapshots in the top-level object or by a range of time of coverage of the top-level object.

Abstract: A method and system are disclosed for transparent backup to a hierarchical storage system. A data management application requests a backup operation, communicating the request using the Network Data Management Protocol with a tape server and a data server. The tape server generates a unique identifier for the data set. In addition, the tape server transfers the data set from the data server to the hierarchical storage system and sends the identifier to the data management application in response to the request. The identifier identifies the data set within the hierarchical storage system. In a certain embodiment, the tape server stores and manages the data set in locations transparent to the data management application. The tape server and data management application may be logically distinct. The data management application may access the data set through the tape server using the identifier.