Patents by Inventor Richard L. Mattson

Richard L. Mattson 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).

  • Patent number: 5551003
    Abstract: Seek affinity is preserved in a segment oriented, cached, log structured array (LSA) of DASDs responsive to accesses dominated by sequential read and random writes of logical tracks stored in the segments. This is achieved by collecting all the write modified read active tracks and clean read active tracks either destaged from the cache or garbage collected from the LSA and rewriting them out to the LSA as segments into regions of contiguous segments of read active tracks. Also, all write modified read inactive tracks and clean read inactive tracks either destaged from cache or garbage collected from the LSA are collected and rewritten out to the LSA as segments into regions of contiguous segments of read inactive tracks. Garbage collection is initiated when the detected free space in a region falls below a threshold and continues until the collected segments exceed a second threshold.
    Type: Grant
    Filed: February 14, 1994
    Date of Patent: August 27, 1996
    Assignee: International Business Machines Corporation
    Inventors: Richard L. Mattson, Jaishankar M. Menon
  • Patent number: 5542066
    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.
    Type: Grant
    Filed: December 23, 1993
    Date of Patent: July 30, 1996
    Assignee: International Business Machines Corporation
    Inventors: Richard L. Mattson, Jaishankar M. Menon
  • Patent number: 5434992
    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.
    Type: Grant
    Filed: September 4, 1992
    Date of Patent: July 18, 1995
    Assignee: International Business Machines Corporation
    Inventor: Richard L. Mattson
  • Patent number: 5416915
    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.
    Type: Grant
    Filed: December 11, 1992
    Date of Patent: May 16, 1995
    Assignee: International Business Machines Corporation
    Inventors: Richard L. Mattson, Jaishankar M. Menon
  • Patent number: 5271012
    Abstract: A method and means for encoding data written onto an array of M synchronous DASDs and for rebuilding onto spare DASD array capacity when up to two array DASD fail. Data is mapped into the DASD array using an (M-1)*M data array as the storage model where M is a prime number. Pairs of simple parities are recursively encoded over data in respective diagonal major and intersecting row major order array directions. The encoding traverse covering a topologically cylindrical path. Rebuilding data upon unavailability of no more than two DASDs merely requires accessing the data array and repeating the encoding step where the diagonals are oppositely sloped and writing the rebuilt array back to onto M DASDs inclusive of the spare capacity.
    Type: Grant
    Filed: February 11, 1991
    Date of Patent: December 14, 1993
    Assignee: International Business Machines Corporation
    Inventors: Miguel M. Blaum, Hsieh T. Hao, Richard L. Mattson, Jaishankar M. Menon
  • Patent number: 5265098
    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.
    Type: Grant
    Filed: August 3, 1990
    Date of Patent: November 23, 1993
    Assignee: International Business Machines Corporation
    Inventors: Richard L. Mattson, Spencer Ng
  • Patent number: 5258984
    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.
    Type: Grant
    Filed: June 13, 1991
    Date of Patent: November 2, 1993
    Assignee: International Business Machines Corporation
    Inventors: Jaishankar M. Menon, Richard L. Mattson, Spencer W. Ng
  • Patent number: 4714992
    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.
    Type: Grant
    Filed: November 26, 1985
    Date of Patent: December 22, 1987
    Assignee: International Business Machines Corporation
    Inventors: Henry M. Gladney, Douglas J. Lorch, Richard L. Mattson
  • Patent number: 4714996
    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.
    Type: Grant
    Filed: November 26, 1985
    Date of Patent: December 22, 1987
    Assignee: International Business Machines Corporation
    Inventors: Henry M. Gladney, Douglas J. Lorch, Richard L. Mattson
  • Patent number: 4463424
    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.
    Type: Grant
    Filed: October 21, 1983
    Date of Patent: July 31, 1984
    Assignee: International Business Machines Corporation
    Inventors: Richard L. Mattson, Juan A. Rodriguez-Rosell