Patents by Inventor Steven Gerdt
Steven Gerdt has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 6336164Abstract: Aspects for preventing deadlock in a log structured array are described. In an exemplary method aspect, and system for providing same, the method includes monitoring available segments to determine when to reserve an open segment, identifying a process type requesting access to the open segment, and limiting access to one process type for the reserved segment. Limiting access further includes limiting access to a garbage collection process.Type: GrantFiled: May 12, 1999Date of Patent: January 1, 2002Assignee: International Business Machines CorporationInventors: Steven Gerdt, Juan Li, Dung Lim Nguyen, Hai-Fang Yun
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Patent number: 6021509Abstract: A method for rebuilding contents of a malfunctioned direct access storage device within a log-structured array is disclosed. In accordance with the method and system of the present invention, each direct access storage device within a log-structured array is divided into multiple segment-columns, and each corresponding segment-column from each direct access storage device within the log-structured array forms a segment. A segment is first located within the direct access storage devices. A determination is made as to whether or not the segment is empty. In response to a determination that the segment is empty, a pointer is moved within a segment-column mapping table from pointing to a segment-column in the malfunctioned direct access storage device to point to a segment-column in a spare direct access storage device of the segment.Type: GrantFiled: May 11, 1998Date of Patent: February 1, 2000Assignee: International Business Machines CorporationInventors: Steven Gerdt, M. Jaishankar Menon, Dung Kim Nguyen
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Patent number: 5832199Abstract: Predictive failure analysis of a storage subsystem is efficiently conducted and data quickly recovered from a failed Read operation. This may be implemented in a storage system including a host coupled to a supervising processor that couples to a parity-equipped RAID storage subsystem having multiple HDAs each including an HDA controller and at least one storage medium. In one embodiment, when an HDA experiences an error during a Read attempt, the HDA transmits a recovery alert signal to the supervising processor; then, the processor and HDA begin remote and local recovery processes in parallel. The first process to complete provides the data to the host, and the second process is aborted. In another embodiment, an HDA's PFA operations are restricted to idle times of the HDA. A different embodiment limits HDA performance of PFA to times when the processor is conducting data reconstruction.Type: GrantFiled: June 23, 1997Date of Patent: November 3, 1998Assignee: International Business Machines CorporationInventors: Norman Apperley, James Thomas Brady, Steven Gerdt, Alden B. Johnson
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Patent number: 5832204Abstract: Predictive failure analysis of a storage subsystem is efficiently conducted and data quickly recovered from a failed Read operation. This may be implemented in a storage system including a host coupled to a supervising processor that couples to a parity-equipped RAID storage subsystem having multiple HDAs each including an HDA controller and at least one storage medium. In one embodiment, when an HDA experiences an error during a Read attempt, the HDA transmits a recovery alert signal to the supervising processor; then, the processor and HDA begin remote and local recovery processes in parallel. The first process to complete provides the data to the host, and the second process is aborted. In another embodiment, an HDA's PFA operations are restricted to idle times of the HDA. A different embodiment limits HDA performance of PFA to times when the processor is conducting data reconstruction.Type: GrantFiled: June 23, 1997Date of Patent: November 3, 1998Assignee: International Business Machines CorporationInventors: Norman Apperley, James Thomas Brady, Steven Gerdt, Alden B. Johnson
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Patent number: 5815650Abstract: Predictive failure analysis of a storage subsystem is efficiently conducted and data quickly recovered from a failed Read operation. This may be implemented in a storage system including a host coupled to a supervising processor that couples to a parity-equipped RAID storage subsystem having multiple HDAs each including an HDA controller and at least one storage medium. In one embodiment, when an HDA experiences an error during a Read attempt, the HDA transmits a recovery alert signal to the supervising processor; then, the processor and HDA begin remote and local recovery processes in parallel. The first process to complete provides the data to the host, and the second process is aborted. In another embodiment, an HDA's PFA operations are restricted to idle times of the HDA. A different embodiment limits HDA performance of PFA to times when the processor is conducting data reconstruction.Type: GrantFiled: June 23, 1997Date of Patent: September 29, 1998Assignee: International Business Machines CorporationInventors: Norman Apperley, James Thomas Brady, Steven Gerdt, Alden B. Johnson
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Patent number: 5764880Abstract: A method for rebuilding contents of a malfunctioned direct access storage device within a log-structured array is disclosed. In accordance with the method and system of the present invention, each direct access storage device within a log-structured array is divided into multiple segment-columns, and each corresponding segment-column from each direct access storage device within the log-structured array forms a segment. A segment is first located within the direct access storage devices. A determination is made as to whether or not the segment is empty. In response to a determination that the segment is empty, a pointer is moved within a segment-column mapping table from pointing to a segment-column in the malfunctioned direct access storage device to point to a segment-column in a spare direct access storage device of the segment.Type: GrantFiled: September 10, 1996Date of Patent: June 9, 1998Assignee: International Business Machines CorporationInventors: Steven Gerdt, M. Jaishankar Menon, Dung Kim Nguyen
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Patent number: 5758050Abstract: A system for managing data storage devices of a data storage subsystem. A data storage system includes a controller coupled to multiple data storage devices. In response to a request, the controller allocates the devices' storage space into a number of storage partitions or "virtual devices." The request specifies the size and function mode for each storage partition. Each storage partition, having the requested size, is operated according to its requested function mode. This involves mapping access commands, which specify virtual addresses, to the proper physical addresses of the appropriate data storage devices.Type: GrantFiled: March 12, 1996Date of Patent: May 26, 1998Assignee: International Business Machines CorporationInventors: James Thomas Brady, Paul T. Burton, Alden B. Johnson, Jaishankar Moothedath Menon, Steven Gerdt
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Patent number: 5717850Abstract: Predictive failure analysis of a storage subsystem is efficiently conducted and data quickly recovered from a failed Read operation. This may be implemented in a storage system including a host coupled to a supervising processor that couples to a parity-equipped RAID storage subsystem having multiple HDAs each including an HDA controller and at least one storage medium. In one embodiment, when an HDA experiences an error during a Read attempt, the HDA transmits a recovery alert signal to the supervising processor; then, the processor and HDA begin remote and local recovery processes in parallel. The first process to complete provides the data to the host, and the second process is aborted. In another embodiment, an HDA's PFA operations are restricted to idle times of the HDA. A different embodiment limits HDA performance of PFA to times when the processor is conducting data reconstruction.Type: GrantFiled: March 12, 1996Date of Patent: February 10, 1998Assignee: International Business Machines CorporationInventors: Norman Apperley, James Thomas Brady, Steven Gerdt, Alden B. Johnson