Richard E Mattson

US Patent:

54349923, Jul 18, 1995

Filed:

Sep 4, 1992

Appl. No.:

7/940560

Inventors:

Richard L. Mattson - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1200
G06F 1300

US Classification:

395425

Abstract:

A method and means is disclosed for dynamically partitioning an LRU cache partitioned into a global cache storing referenced objects of k different data types and k local caches storing objects of a single type. Referenced objects are stored in the MRU position of the global cache and overflow is managed by destaging the LRU object from the global to the local cache having the same data type. Dynamic partitioning is accomplished by recursively creating and maintaining from a trace of objects an LRU list of referenced objects and associated data structures for each subcache, creating and maintaining a multi-planar array of partition distribution data from the lists and the trace as a collection of all possible of maximum and minimum subcache sizing, optimally resizing the subcache partitions by applying a dynamic programming heuristic to the multiplanar array, and readjusting the partitions accordingly.

US Patent:

54169151, May 16, 1995

Filed:

Dec 11, 1992

Appl. No.:

7/989245

Inventors:

Richard L. Mattson - San Jose CA
Jaishankar M. Menon - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1116
G06F 1206

US Classification:

395425

Abstract:

A method and system for minimizing seek affinity and enhancing write sensitivity in a direct access storage device (DASD) array are disclosed. SEEK affinity and WRITE efficiency are preserved in which logical cylinders, as recorded on the DASD array, are managed as individual log structured files (LSF). Tracks or segments of data and parity blocks having the same or different parity group affinity and stored on the same or different DASD cylindrical addresses are written into a directory managed buffer. Blocks having the same parity affinity and written to counterpart cylinders are written out from the buffer to spare space reserved as part of each DASD cylinder. Otherwise, blocks are updated in place in their DASD array location.

US Patent:

52589846, Nov 2, 1993

Filed:

Jun 13, 1991

Appl. No.:

7/714969

Inventors:

Jaishankar M. Menon - San Jose CA
Richard L. Mattson - San Jose CA
Spencer W. Ng - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1120

US Classification:

371 101

Abstract:

A method and means in which data and parity blocks forming parity groups together with spare blocks are distributed over array block locations according to at least one combinatorial design, each group having N data and P parity blocks. The combinatorial designs yield uniform or balanced loading thereby minimizing the number of accesses to reconstruct missing data and parity blocks and their copyback into spare block locations, and, minimize the number of accesses to the reconstructed data referenced subsequent to its copyback. Distributions of the spare block capacity of one or two DASDs are shown over single and multiple arrays and shared among multiple arrays. Parity block distribution although ancillary to spare distribution enhances throughput and reduces the number of accesses for rebuild etc.

US Patent:

44634242, Jul 31, 1984

Filed:

Oct 21, 1983

Appl. No.:

6/544331

Inventors:

Richard L. Mattson - San Jose CA
Juan A. Rodriguez-Rosell - Gaithersburg MD

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1300

US Classification:

364300

Abstract:

Short traces of consecutive CPU references to storage are accumulated and processed to ascertain hit ratio as a function of cache size. From this determination, an allocation of cache can be made. Because this determination requires minimal processing time, LRU-referenceable memory space among concurrently executing sequential processes is used dynamically by a CPU cache manager.

US Patent:

52650987, Nov 23, 1993

Filed:

Aug 3, 1990

Appl. No.:

7/562188

Inventors:

Richard L. Mattson - San Jose CA
Spencer Ng - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1100

US Classification:

371 111

Abstract:

A method and apparatus are disclosed which minimize the additional read and write loading for each remaining DASD in a DASD array occasioned by a single point of failure where subsets of DASDs may accessed asynchronously (RAID 4 or RAID 5). In this method, parity groups are written across the array in a pattern forming a balanced incomplete block design or the equivalent. In the event of failure of a DASD in the array, then any additional loading resulting from the failure is uniformly spread among the remaining DASDs.

US Patent:

47149965, Dec 22, 1987

Filed:

Nov 26, 1985

Appl. No.:

6/801896

Inventors:

Henry M. Gladney - Saratoga CA
Douglas J. Lorch - San Jose CA
Richard L. Mattson - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 900

US Classification:

364300

Abstract:

In a distributed processing system having a source node accessing data objects from a database and a replica node storing replicas of requested source data objects received from the source location, the impact to replicas caused by a change in a source data object is calculated by assigning a version number to the change. An identifier of the portion of the source database affected by the change is generated, as well as a list of replicas containing objects from the affected portion of the database. For a replica location communicating with the source location, a table of the replicas from the list is then recorded along with the version number for communicating to the replica location.

US Patent:

55420664, Jul 30, 1996

Filed:

Dec 23, 1993

Appl. No.:

8/172527

Inventors:

Richard L. Mattson - San Jose CA
Jaishankar M. Menon - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 1200

US Classification:

395463

Abstract:

A controller for a disk array with parity and sparing includes a non-volatile cache memory and optimizes the destaging process for blocks from the cache memory to both maximize the cache hit ratio and minimize disk utilization. The invention provides a method for organizing the disk array into segments and dividing the cache memory into groups in order of least recently used memory locations and then determining metrics that permit the disk array controller to identify the cache memory locations having the most dirty blocks by segment and group and to identify the utilization rates of the disks. These characteristics are considered to determine when, what, and how to destage. For example, in terms of maximizing the cache hit ratio, when the percentage of dirty blocks in a particular group of the cache memory locations reaches a predetermined level, destaging is begun. The destaging operation continues until the percentage of dirty blocks decreases to a predetermined level. In terms of minimizing disk utilization, all of the dirty blocks in a segment having the most dirty blocks in a group are destaged.

US Patent:

47149922, Dec 22, 1987

Filed:

Nov 26, 1985

Appl. No.:

6/801897

Inventors:

Henry M. Gladney - Saratoga CA
Douglas J. Lorch - San Jose CA
Richard L. Mattson - San Jose CA

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 100

US Classification:

364200

Abstract:

In a distributed processing system network in which at least one node operates as a source location having access to data objects of a database, and at least one other node operates as a replica location storing replicas of data objects from the source location, managing obsolescence of the replicas is performed by having the replica locations submitting requests to the source location for ascertaining obsolescence of data objects. The source location, responsive to a request from a requesting replica location, extracts identifiers of a set of obsolete objects and communicates them to the requesting replica location. Upon receiving the identifiers, the requesting location renders inaccessible those data objects corresponding to the identifiers received. The source location then removes those identifiers that have been communicated to the requesting replica location.