1
Philip K Chai, Chan Y Ng, John R Paveza, Lloyd R Shipman Jr, Christ J Xydes: Fault tolerant data storage subsystem employing hierarchically arranged controllers. International Business Machines Corporation, Esther Klein, Andrew J Dillon, April 2, 1996: US05504882 (184 worldwide citation)

A fault tolerant disk storage subsystem which includes a multipath dynamically alterable hierarchical arrangement of storage device controllers. Multiple storage device controllers are provided which are each adapted to emulate a storage device and which each include a cache memory which has multipl ...


2
Brent C Beardsley, Joel H Cord, Joseph S Hyde II, Vernon J Legvold, Carol S Michod, Gary E Morain, Chan Y Ng, John R Paveza, Lloyd R Shipman Jr: Performance enhancement system and method for a hierarchical data cache using a RAID parity scheme. International Business Machines Corporation, Baker Maxham Jester & Meador, June 3, 1997: US05636359 (90 worldwide citation)

A system and method for reducing device wait time in response to a host initiated write operation modifying a data block. The system includes a host computer channel connected to a storage controller which has cache memory and a nonvolatile storage buffer in a first embodiment. An identical system m ...


3
Brent C Beardsley, Eugene P Hefferon, Kenneth R Lynch, Stephen W Schimke, Lloyd R Shipman Jr, Susan M Wethington: Device initiated partial system quiescing. International Business Machines Corporation, November 13, 1990: US04970640 (37 worldwide citation)

A data processing system includes a plurality of host systems and peripheral subsystems, particularly data storage subsystems. Each of the data storage subsystems includes a plurality of control units attaching a plurality of data storage devices such as direct access storage devices (DASD) for stor ...


4
Dennis R Escola, Steven D Gerdt, Barrie N Harding, Paul W Hunter, Lloyd R Shipman Jr: Storage subsystem having a modifiable key-lock. International Business Machines Corporation, Baker Maxham Jester & Meador, July 11, 1995: US05432929 (19 worldwide citation)

A data storage and retrieval system is described having one or more key-lock storage areas which can be modified under the control of commands received from an attached computer. Each key-lock is stored in nonvolatile data storage. A key-lock contains a key field and a lock field. The contents of th ...


5
James C Chen, Joseph S Glider, Lloyd R Shipman Jr, Jesse I Stamness: Method and system for enhanced data management efficiency in memory subsystems utilizing redundant arrays of disk memory devices and a nonvolatile cache. International Business Machines Corporation, Esther Klein, Andrew J Dillon, May 27, 1997: US05634109 (16 worldwide citation)

The present system may be utilized to minimize access performance penalties in memory subsystems which utilize redundant arrays of disk memory devices. Redundant arrays of disk memory devices provide levels of reliability which are not available with single storage devices; however, the redundancy c ...


6
Dennis R Escola, Steven D Gerdt, Barrie N Harding, Lloyd R Shipman Jr: Disk storage system with fault tolerant media maintenance. International Business Machines Corporation, G Marlin Knight, Esther E Klein, May 30, 1995: US05421003 (14 worldwide citation)

A data storage system is described which provides for fault tolerance during execution of a media maintenance program on a selected track of nonvolatile data storage. Checkpoint data for the media maintenance program is stored in nonvolatile storage prior to writing control information on the select ...


7
Lloyd R Shipman Jr: Method and system for separate data and media maintenance within direct access storage devices. International Business Machines Corporation, Esther Klein, Andrew J Dillon, November 14, 1995: US05467361 (13 worldwide citation)

The present application may be utilized for enhanced maintenance of data stored on storage media within a data processing system storage subsystem. Data to be stored is first subdivided into multiple blocks and subblocks, segments or tracks. Each subdivision of data is then analyzed and appropriate ...


8
Janet S Anglin, Lloyd R Shipman Jr: Method and apparatus for executing critical disk access commands. International Business Machines Corporation, G Marlin Knight, Paik Saber, June 27, 1995: US05428802 (13 worldwide citation)

The present invention is a controller and a method for its use in a disk data storage and retrieval system. The controller is of the type which associates a file mask with a sequence of commands. The controller has means for executing a critical-section-start (CSS) command received from the host com ...