Abstract: Data compression efficacy in a data storage system is analyzed, and data compression modified in accordance with the results of such analysis, thereby saving otherwise wasted processor time when data compression is poor. Multiple input data blocks are received for storage in a data storage subsystem, and a predetermined compression process is applied thereto. Application of the predetermined compression process is evaluated according to a predetermined compression criteria. If the compression fails to satisfy the predetermined compression criteria, application of the predetermined compression process ceases.

Abstract: A storage controller conditions host access to stored data objects upon host provision of a proposed key with matching or other prescribed relation to a security key stored in host-inaccessible metadata that is associated with the stored data object. The security key may be established upon writing the data or allocating storage space, for example. This enables the storage controller or device to be attached directly to a network without compromising security or having to add an intermediate server to perform security functions. Another implementation concerns sound recording playback devices that only play sound tracks for which the user has purchased an appropriate security key.

Abstract: Data is rapidly restored from a backup copy, and user access of the restored data further expedited by providing on-demand output of logged changes to the backup data. Contents of the backup data are the same as contents of corresponding primary data at a designated time when the backup data was created. If any changes to the primary data are received by the system after creating the backup copy, the changes are stored by the system in a change log. In one embodiment, where the system stores changes in multiple logs, the logs may be consolidated and sorted according to an appropriate schedule. Whenever primary data becomes unavailable, the system starts to apply logged changes to the backup copy right away, using the consolidated and sorted change log. When the system receives user requests to access the primary data, the system determines whether the log contains any changes that have not been applied to the backup data.

Abstract: A storage-and-host-controller-managed outboard data management tool is described wherein the host controller defines logical paths between various storage controllers and data storage devices, and the storage controller manages the movement of data to and from the various data storage devices while only sending data to the host processorg if necessary.

Abstract: A host-independent storage facility selectively provides data-dependent security by initially storing a security key in association with a storage region, where that key must be presented by any host seeking access to the region. The storage system includes a storage controller coupled to a digital data storage and one or more hosts. Initially, the controller receives a set-access-key command from one of the hosts, identifying a storage region, an operation parameter identifying prohibited types of storage operations, and a reference access key. The controller stores the access key and the operation parameter in a reference location associated with the identified storage region. Later, the controller may receive storage access requests from the hosts. Requests include an identification of a requested storage region, an access type, and an input access key. In response, the controller retrieves the reference access key and operation parameter associated with the requested storage region.

Abstract: A storage controller conditions host access to stored data objects upon host provision of a proposed key with matching or other prescribed relation to a security key stored in host-inaccessible metadata that is associated with the stored data object. The security key may be established upon writing the data or allocating storage space, for example. This enables the storage controller or device to be attached directly to a network without compromising security or having to add an intermediate server to perform security functions. Another implementation concerns sound recording playback devices that only play sound tracks for which the user has purchased an appropriate security key.

Abstract: A storage-and-host-controller-managed outboard data management tool is described wherein the host controller defines logical paths between various storage controllers and data storage devices, and the storage controller manages the movement of data to and from the various data storage devices while only sending data to the host processor if necessary.

Abstract: An expedited data backup is performed by creating a duplicate set of pointers to a current dataset already identified by an original pointer set, then designating the dataset as a backup dataset, and thereafter preventing changes to the pointed-to-data and the duplicate pointers, where changes to the current dataset are nonetheless effected by storing new data and modifying the original pointer set alone. More specifically, the backup involves an original dataset having multiple subparts residing at various original storage locations, which are pointed-to by a primary set of pointers. A virtual backup copy is created by duplicating the primary set of pointers to create a backup set of pointers. The backup set of pointers are entered in a backup list, in association with the virtual backup copy and the original dataset. To preserve the backup copy, the system prevents changes to the original dataset and the backup set of pointers.

Abstract: A data storage system includes an outboard data transfer module that directs data transfer operations without requiring substantial host involvement. This subsystem includes a host computer, one or more digital data storage devices, one or more device controllers interposed between the host computer and the storage devices, and a outboard data manager coupled to the host and the device controllers. Data transfer operations are initiated when the outboard data manager receives a data transfer request from the host. The request identifies the type of operation, resulting target format, source data residing on one or more source devices, and one or more target devices. In response to this request, the outboard data manager retrieves a copy of the source data from the source device(s), formats target data according to host instruction, and then transmits the copy to the target device(s) for storage therein.

Abstract: A system and method for demand-based data recovery operating in a computerized data processing system that includes a computer platform operable under the control of system data, including system programs, catalogs, directories, inventories and the like, and one or more user applications operable in conjunction with user data. The data processing system includes a data backup and recovery system for periodically transferring data between one or more primary data storage resources and one or more secondary data storage resources. The demand-based system and method operate to recover data from the secondary data storage resources to the primary data storage resources following a disaster event resulting in the loss of all or a portion of the data on the primary data storage resources. In accordance therewith, the system data is first recovered from the secondary data storage resources to the primary data storage resources.