Abstract: A method and system for retrieving data that is stored on a backup or secondary storage system located at a remote location to a local storage system. Restoring of backup data involves the transferring of a point-in-time copy of primary system data from a secondary storage system to the local system. The point-in-time copy is created on the secondary system using an asynchronous remote copy scheme. The point-in-time copy that is restored may be either an entire volume or portions thereof.

Abstract: A data structure, method, and computer system for fast data copy is provided which uses control structures in a data copy track table. The control structures include a physical location pointer, a physical location pointer flag, a forward track pointer and a backward source pointer. These control structures are used in an update-in-place architecture. Requests for source or target data updates do not require additional write cycles.

Abstract: A method and system for retrieving data that is stored on a backup or secondary storage system located at a remote location to a local storage system. Restoring of backup data involves the transferring of a point-in-time copy of primary system data from a secondary storage system to the local system. The point-in-time copy is created on the secondary system using an asynchronous remote copy scheme. The point-in-time copy that is restored may be either an entire volume or portions thereof.

Abstract: A data structure, method, and computer system for fast data copy is provided which uses control structures in a data copy track table. The control structures include a physical location pointer, a physical location pointer flag, a forward track pointer and a backward source pointer. These control structures are used in an update-in-place architecture. Requests for source or target data updates do not require additional write cycles.

Abstract: A storage control system and method for storing and retrieving data to and from a tape backup system that is located remotely from a primary host system. The primary system is coupled to a remote storage system for remote copy applications. The tape backup system is coupled to the remote storage system and operated at the remote site. Conducting control signals through the primary storage controller to the remote storage controller enables control over the tape backup system from the local or primary site. Data can be backed up to the tape system from the remote storage site which enables the local host to perform applications during the backup window. Data can also be restored from the tape system to the remote storage system and transferred back to the primary system via the communications link.

Abstract: The knowledge based system identifies the occurrence of a failure within the customer equipment and functions using its rules, hypotheses and collected data to isolate the functional resource which is the source of the error in the customer equipment and, whenever possible, "fence" or isolate the failed functional resource that has caused the error. In addition, the knowledge based system makes use of resource related rules to remove a resource or set of resources available for concurrent other failure management operations. The resource related rules allow resources to function in any one non-operational or operational mode or to functional simultaneously in multiple non-operational modes.

Abstract: The knowledge based system functions in a machine initiated maintenance environment to provide efficient and timely maintenance of customer equipment. The knowledge based system provides the failure evaluation function through the use of an expert or knowledge based system that is installed in the customer equipment. The knowledge based system makes use of a set of rules and hypotheses to operate on data collected from various points within the customer equipment to monitor the operational integrity of the customer equipment. This knowledge based system identifies the occurrence of a failure within the customer equipment and functions using its rules, hypotheses and collected data to isolate the source of the error in the customer equipment and, whenever possible, "fence" or isolate the failed field replaceable unit that has caused the error.

Abstract: A disk storage system that writes multiple copies of records directed to user-specified volumes. A plurality of spaced apart control units interconnected by direct data links and a corresponding plurality of sets of recording means communicate over the direct data links when a write request is received by one control unit to cause one volume in each set of recording means to write a copy of the received record.

Abstract: A hole angularity gauge is disclosed which is small, durable and easily calibrated. The gauge includes a probe which is sized to fit the hole to be measured. The probe is coupled to a lever, both of which are pivotal about a first pivot point whereby the lever is angularly displaced in response to any angular displacement of the probe. The gauge further includes a linkage asembly that amplifies the angular displacement of the lever. The linkage assembly includes a pointer which is adapted to pivot about a second pivot point. The pointer is coupled to the lever at a point that is displaced from the second pivot point such that the pointer is angularly displaced in response to any angular displacement of the lever whereby the angle that the pointer is displaced is a multiple of the angle that the lever is displaced. The probe further includes apparatus for indicating the angular displacement of the probe and, accordingly, indicating the angularity of the hole.