Abstract: A method, computer program product, and cache management system for receiving an indication of a data portion update within an electromechanical storage system. Information concerning the data portion update is provided to at least one proprietary, solid-state, non-volatile, cache memory system. The proprietary, solid-state, non-volatile, cache memory system is associated with at least a first of a plurality of computing devices and is not associated with at least a second of the plurality of computing devices.

Abstract: A system, computer-implemented method, and a computer program product for monitoring a first data portion written to a first storage device accessible by a first computing device. At least a second data portion written to at least a second storage device accessible by at least a second computing device is monitored. Recovery data is written to a recovery storage device external to and accessible by the first and the at least a second computing devices, wherein the recovery data is based, at least in part, upon the first and second data portions.

Abstract: A method, computer program product, and cache management system for receiving an indication of a data portion update within an electromechanical storage system. Information concerning the data portion update is provided to at least one proprietary, solid-state, non-volatile, cache memory system. The proprietary, solid-state, non-volatile, cache memory system is associated with at least a first of a plurality of computing devices and is not associated with at least a second of the plurality of computing devices.

Abstract: A system, method and computer program product for receiving on a non-volatile, solid-state, cache memory system, a data segment, including a plurality of data elements, from one or more of a volatile, solid-state, cache memory system and a non-volatile, electromechanical memory system. The data segment may be stored on the non-volatile, solid-state, cache memory system. Each data element includes one or more data extents.

Abstract: A system and method for storing data, the system having one or more storage devices, caches data from a sender into a first random-access structure located in a first cache level, caches data from the first cache level into a log structure located in a second cache level, and stores data from CL into a second random-access structure located in a storage level, wherein CL is the first cache level or the second cache level. In further embodiments of the invention, the second cache level caches in the log structure parity data for the data cached in the log structure. In a still further embodiment of the invention, the storage level stores in the second random-access structure parity data for the data stored in the second random-access structure.

Abstract: There is disclosed apparatus and methodology for enhancing computer system data transfer when writing to network attached storage systems employing FC-2 fibrechannel protocol by dynamically reconfiguring a fibrechannel switch in response to map/unmap command controls issued by a disk drive aggregator. The reconfiguration involves fabrication of a dynamic map table having sets of fibrechannel FC-2 header fields and their corresponding new or proxy destination IDs (which correspond to the switch's output ports), and fabrication of both an input frame header buffer for temporary storage purposes and a frame header field selector (which can be a frame header mask) containing only relevant information. The input frame header is temporarily stored in the buffer and the field selector is used to obtain a “distilled” input header which is compared with the dynamic map table of stored header fields to obtain a match.

Abstract: A system and method for cleaning a log structure, the log structure including one or more segments, each segment including live data, orders the one or more segments into a hot list according to age, with the youngest segment at the beginning of the hot list and the oldest segment at the end of the hot list, the youngest segment being the most recently used segment and the oldest segment being the least recently used segment, pushes one or more of the oldest segments in the hot list to a cleaning matrix, the cleaning matrix grouping segments according to age and percent of live data in the segment, traverses the cleaning matrix looking for a segment, determines whether enough live data has been found to write a complete segment, sequentially repeats the previous two processes until enough live data has been found to write a complete segment, reads data from the one or more found segments, and writes the read live data into an unused segment.

Abstract: A system and method for expanding a log structure in a disk array, the disk array being expanded from M-width to N-width, the disk array including a storage level, the log structure including one or more sequential used segments, the one or more sequential used segments including live data, locates one or more sequential used segments, writes live data from the one or more located segments to the storage level, enlarges the size of the one or more located segments from M-width to N-width, and places the one or more enlarged segments on a first free segment list.

Abstract: A high performance data path for performing XOR on the fly. A first memory is connected to a first bus and a second memory is connected to a second bus selectively coupled to the first bus. Logic for performing an XOR can be switched into connection with the first and second bus for XORing data in a buffer with the data passed from one of the memories to the other memory. The result is replaced into the buffer to permit successive XORing. When reading from an interrelated group of disks such as a RAID 3 group, the data path permits an N-1 and go mode in which a read does not wait for data from the last disk to retrieve its data sector. If the last disk contains data (as opposed to parity) the data is obtained from the XORed data in the XOR buffer of the high performance data path. For writing data, the XOR on the fly generates the parity sector for writing at the completion of a write to an interrelated group of disks.

Abstract: A data storage system has at least three data storage disks and a plurality of processing nodes in communication with the data storage disks. Each of the processing nodes shares access to the data storage disks, and each of the processing nodes includes a distributed lock manager that allows or denies access to selected stripes of data storage sectors on any of the data storage disks. Each of the processing nodes includes an interface to a private communication link to a single one of a plurality of host operating systems.

Abstract: A recovery method for use in a data storage system in which a plurality of data storage devices are connected to each of two communication paths. A switch may route requests to either of the two communication paths. With one data storage controller in communication with the data storage devices over a first path and a second data storage controller in communication with the data storage devices over a second path, upon detection of a malfunction on the first path, a data storage controller may request access to the other path. Thereafter, the controller may be switched into connection with the remaining operable path so as to share that path with the other controller.

Abstract: A recovery method and fail-over switch for use in a data storage system in which a plurality of data storage devices are connected to each of two communication paths. The switch may route requests to either of the two communication paths. Switching may be accomplished by two fail-over switches connected to each other and each in connection with one of the two communication paths. With one data storage controller in communication with the data storage devices over a first path and a second data storage controller in communication with the data storage devices over a second path, the fail-over switches may be used upon detection of a malfunction on one path to switch a controller into connection with the remaining operable path so as to share that path with the other controller.

Abstract: A method for handling data in a plurality of data storage disks having user data sectors and corresponding parity sectors, the method being used when the disks are being operated in a non-degraded or a degraded mode wherein a non-volatile RAM is used in an array control processor which controls the operation of such disks. When new data is to be written into the array, the non-volatile RAM stores information identifying the array, the starting sector into which data is to be written and the number of sectors to be used for writing the new data so that parity and data entries in corresponding sectors can be matched when a power failure occurs. Further, when opening a new array, the data and parity entries in corresponding sectors can be matched and verified, the operation for such matching being performed in between other operations that are being performed by the control processors (i.e., in the "background" thereof).

Abstract: A method for providing on-line replacement of a module which is at a specified position in an array of modules connected to a common control processor so that all other modules in the array can continue operating during the replacement operation. When the module is removed an indication is provided to the control processor showing that removal has occurred and identifying the position thereof. When the replacement has occurred an indication thereof is provided to the control processor, the replacement module is tested, and the state of the replacement module is updated to place it in the same state it would have been in if it had not been replaced.

Abstract: A method for handling data in a plurality of data storage disks having user data sectors and corresponding parity sectors, the method being used when the disks are being operated in a degraded mode wherein data in sectors of an inoperative user data disk are reconstructed from data in the corresponding sectors of the other user data disks and the corresponding parity entry. The reconstructed user data in a user data sector of the inoperative disk is written into the corresponding parity sector in place of the parity entry therein, before any new data is written into the corresponding sector of an operative disk. Information identifying the inoperative disk is written into a specified identification region of the parity disk to indicate that such operation has occurred. The new data is then written into the corresponding sector of the operative disk.