Steven R Lowe

US Patent:

6615318, Sep 2, 2003

Filed:

Jan 22, 2002

Appl. No.:

10/055633

Inventors:

Thomas Charles Jarvis - Tucson AZ
Steven Robert Lowe - Tucson AZ
Bruce McNutt - Gilroy CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

B06F 1200

US Classification:

711133

Abstract:

In a cache management system multiple cache lists are utilized, where each entry in a list names at least one corresponding data item in cache. A cache manager always demotes cache list entries from a âcurrent removal listâ (and demotes or destages the corresponding data items from cache) until that list is exhausted and another list rotates into the function of current removal list. A prescribed order is established for rotating the role of current removal list. In response to prescribed activities of data items in cache, new cache list entries are added nearer or farther from the current removal list according to the prescribed order and the data items priorities.

US Patent:

6785771, Aug 31, 2004

Filed:

Dec 4, 2001

Appl. No.:

10/005003

Inventors:

Kevin John Ash - Tucson AZ
Brent Cameron Beardsley - Tucson AZ
Michael Thomas Benhase - Tucson AZ
Thomas Charles Jarvis - Tucson AZ
Steven Robert Lowe - Tucson AZ
David Frank Mannenbach - Tucson AZ

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1200

US Classification:

711136, 711112, 711114, 711133, 711134, 711143

Abstract:

Provided is a method, system, and program for destaging data from a first computer readable medium to a second computer readable medium. A list of entries indicating data blocks in the first computer readable medium is scanned. For each entry scanned, a determination is made as to whether the data block indicated in the scanned entry satisfies a criteria. If the data block indicated in the scanned entry satisfies the criteria, then a destage operation is called to destage the data block in the scanned entry from the first computer readable medium to the second computer readable medium. If the called destage operation is not initiated, then the scanned entry is removed from the cache list. The removed scanned entry is added to one destage wait list. During one destage operation, data blocks indicated in entries in the destage wait list are destaged.

US Patent:

6948009, Sep 20, 2005

Filed:

Jun 4, 2002

Appl. No.:

10/163219

Inventors:

Thomas Charles Jarvis - Tucson AZ, US
Steven Robert Lowe - Tucson AZ, US
Sam Clark Werner - Tucson AZ, US
William Dennis Williams - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F003/00
G06F013/00

US Classification:

710 17, 710 5, 710 31, 710 32, 710 39, 712405

Abstract:

Provided are a method, system, and program for increasing processor utilization. A list of work is divided for processing among a plurality of processes, wherein a process is allocated a part of the list of work to process, and the processes execute in parallel. If a process completes the list of work allocated to the process then the process is made available on an available process queue. Before a process performs any work, the process reads the available process queue and determines if any process is available to share the work. If so, the work is split up between the examining process and the available process. In one implementation, the work involves scanning a cache and if necessary destage data.

US Patent:

7051174, May 23, 2006

Filed:

Sep 24, 2002

Appl. No.:

10/255026

Inventors:

Kevin John Ash - Tucson AZ, US
Vernon J. Legvold - Tucson AZ, US
Steven Robert Lowe - Tucson AZ, US
David Frank Mannenbach - Tucson AZ, US
Carol Santich Mellgren - Tucson AZ, US
Kenneth Wayne Todd - Tucson AZ, US
William Dennis Williams - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 12/02

US Classification:

711162, 711113, 711114, 711161, 711163, 711165, 711166, 707204, 707205, 714 5, 714 6

Abstract:

Provided are a method, system, and program for maintaining data in a first cache and second cache, wherein a backup cache maintains a backup copy of data in the first cache, and wherein the first cache is used to cache a first set of data in a storage system and the second cache is used to cache a second set of data in the storage system. An unavailable state of the first cache is detected. In response to detecting the unavailable state, requests to the first set of data are blocked and at least one space in the second cache is allocated for data in the backup cache. Requests to the first set of data are allowed to proceed after the at least one space is allocated in the second cache and before the data in the backup cache is copied to the at least one allocated space in the second cache. The data from the backup cache is copied to the allocated at least one space in the second cache after the requests to the first set of data are allowed to proceed.

US Patent:

7171516, Jan 30, 2007

Filed:

Sep 29, 2003

Appl. No.:

10/674871

Inventors:

Steven R. Lowe - Tucson AZ, US
Kevin J. Ash - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 12/00

US Classification:

711113

Abstract:

A data storage control unit is coupled to one or more host devices and to one or more physical storage units, the physical storage units collectives configured as a plurality of logical storage ranks. The storage control unit receives and processes write requests from the host devices and directs that data updates be stored in a temporary storage. The data updates are subsequently destaged to the logical ranks. Write requests are processed at a predetermined rate relative to the rate at which destages are performed (destage mode or rate). The storage control unit evaluates workload conditions of the temporary storage and modifies the destage mode if the temporary storage is in danger of becoming backlogged or if an actual backlog is created, thereby applying a “throttle” to the host write requests. Thus, method, apparatus and program product are provided to dynamically modify a level of throttling whereby through-put of a host device is substantially maintained.

US Patent:

7191207, Mar 13, 2007

Filed:

Jun 11, 2003

Appl. No.:

10/459645

Inventors:

Lawrence C. Blount - Tucson AZ, US
Thomas C. Jarvis - Tucson AZ, US
Steven R. Lowe - Tucson AZ, US
David F. Mannenbach - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G09F 15/173
G06F 9/00

US Classification:

709200, 711112, 370208, 709105

Abstract:

An apparatus and a method to allocate device adapter bandwidth, where that device adapter is disposed in an information storage and retrieval system capable of communicating with one or more host computers, and where that device adapter interconnects a data cache with information storage devices. The data storage and retrieval system receives a plurality of requests from the host computers to read information from, or to write information to, information storage devices. The method determines a read/write request ratio and a non-volatile storage utilization ratio. The method allocates device adapter bandwidth based upon the read/write request ratio and/or the non-volatile storage utilization ratio.

US Patent:

7421535, Sep 2, 2008

Filed:

May 10, 2004

Appl. No.:

10/843150

Inventors:

Thomas Charles Jarvis - Tucson AZ, US
Michael Howard Hartung - Tucson AZ, US
Karl Allen Nielsen - Tucson AZ, US
Jeremy Michael Pinson - Tucson AZ, US
Steven Robert Lowe - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 12/00
G06F 12/16

US Classification:

711113, 711112, 711111, 711101, 711118, 711135

Abstract:

Provided are a method, system, and program for destaging a track from cache to a storage device. The destaged track is retained in the cache. Verification is made of whether the storage device successfully completed writing data. Indication is made of destaged tracks eligible for removal from the cache that were destaged before the storage device is verified in response to verifying that the storage device is successfully completing the writing of data.

US Patent:

7680982, Mar 16, 2010

Filed:

Feb 20, 2007

Appl. No.:

11/676634

Inventors:

Kevin John Ash - Tucson AZ, US
Lokesh Mohan Gupta - Tucson AZ, US
Steven Robert Lowe - Tucson AZ, US
Alfred Emilio Sanchez - Tucson AZ, US
Kenneth Wayne Todd - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 12/00

US Classification:

711113, 711154, 711158, 711162, 711165, 707204, 714 5, 714 6

Abstract:

In a data storage subsystem with disk storage and a pair of clusters, one set of DASD fast write data is in cache of one cluster and in non-volatile data storage of the other. In response to a failover of one of the pair of clusters to a local cluster, the local cluster converts the DASD fast write data in local cache to converted fast write data to prioritize the converted data for destaging to disk storage. In response to failure to destage, the local cluster allocates local non-volatile storage tracks and emulates a host adapter to store the converted fast write data by the local non-volatile storage, reconverting the converted fast write data of the non-volatile storage to local DASD fast write data stored in the local non-volatile storage and stored in the local cache storage.