Patents Represented by Attorney, Agent or Law Firm Pryor A. Garnett
  • Patent number: 5343340
    Abstract: Apparatus and method are provided for servo signal demodulation using a servo processor and a partial-response maximum-likelihood (PRML) data channel in a disk file. A servo burst timing window is identified. Then a plurality of digital samples are detected with the PRML data channel responsive to identifying the servo burst timing window. Sequential sets of the detected digital samples are accumulated by the PRML data channel and transmitted to the servo processor. The digital samples are processed by the servo processor for providing servo phase information that is used to provide servo position information.
    Type: Grant
    Filed: December 31, 1992
    Date of Patent: August 30, 1994
    Assignee: International Business Machines Corporation
    Inventors: Zine-Eddine Boutaghou, Dana H. Brown, Kevin J. Erickson, Richard Greenberg
  • Patent number: 5329535
    Abstract: An ECC decoder is provided for use with variable block lengths of Reed-Solomon (RS) code for on-the-fly detecting of multiple errors and correction of one error byte per interleave in data recorded on a storage medium in blocks. Each data block includes variable length data subblocks equal to N*L, where N equals a variable number of bytes per interleave and L equals the interleave degree. The ECC decoder includes a delay register for sequentially receiving consecutive N*L data bytes of the data subblocks at a delay register data input and for sequentially transferring the consecutive N*L data bytes of data subblocks to a delay register data output. Each subblock contains a predetermined number of error check bytes M. Multiple M partial syndrome generators sequentially receive the consecutive subblocks of data and generate partial syndromes. The generated partial syndromes are compared to identify agreement.
    Type: Grant
    Filed: April 30, 1992
    Date of Patent: July 12, 1994
    Assignee: International Business Machines Corporation
    Inventor: Jonathan D. Coker
  • Patent number: 5327440
    Abstract: Viterbi trellis coding methods and Viterbi detector apparatus are provided for detecting trellis coded data. A systolic array Viterbi detector recursively calculates path metrics and partial sums of metric update equations to determine codeword sequences having minimum mean squared error for Viterbi-type maximum-likelihood data detection. The systolic array Viterbi detector is arranged to eliminate redundant calculations and simplify hardware requirements. Modified butterfly trellis geometries and rotating state metrics arrangements are provided for simplifying the Viterbi detector.
    Type: Grant
    Filed: October 15, 1991
    Date of Patent: July 5, 1994
    Assignee: International Business Machines Corporation
    Inventors: Lyle J. Fredrickson, James W. Rae
  • Patent number: 5313589
    Abstract: A controller device interfacing method and a low level device interface are provided for use between at least one controller and a plurality of devices in a direct access storage device. Message and command and data information are received and transmitted between the controller and the device. Responsive to a received predetermined read data command, read data function hardware transmits the requested data to the controller. Responsive to a received predetermined write data command, write data function hardware writes the received data from the controller to a device. Received message information is blocked from received data information so that message information is transmitted at any time within and between data information transmissions. The low level device interface supports two wire serial data transfer and provides improved data rate performance.
    Type: Grant
    Filed: March 12, 1993
    Date of Patent: May 17, 1994
    Assignee: IBM Corporation
    Inventors: James E. Donaldson, Gregory G. Floryance, Steven A. Schmitt
  • Patent number: 5311461
    Abstract: In a computer system in which conflicting requests for resources are prioritized, a programmable priority determination method and system. Relative priority between competing sources or requests is represented by a control word (priority code). The control word includes bits identifying the highest priority source, and rotation and skip bits determining the order or priority among the other sources. The control word is used to pre-set a priority circuit which then selects from among competing resource requests based on the priority represented by the control word. Relative priority between the sources can be changed during operation of the computer system by creating a new control word and applying it to the priority circuit.
    Type: Grant
    Filed: December 30, 1988
    Date of Patent: May 10, 1994
    Assignee: International Business Machines Corp.
    Inventor: Patrick W. Gallagher
  • Patent number: 5297248
    Abstract: A method for displaying statements of a computer program during an animation of the program's execution, the display using multiple colors to identify statements based on their respective frequency of execution, is disclosed. As a program statement becomes the current executed statement during the animation, the statement's frequency of execution is calculated as the number of times the statement has been executed so far during the animation, divided by the total number of statement executions throughout the animation. A display color is assigned based on whether the statement's execution frequency has reached one of two or more thresholds. The multi-hued display of program statements based on thresholds of execution frequency assists the programmer in understanding the operation of the program.
    Type: Grant
    Filed: October 7, 1992
    Date of Patent: March 22, 1994
    Assignee: International Business Machines Corporation
    Inventor: Andrew L. Clark
  • Patent number: 5289097
    Abstract: A spindle motor control method and apparatus for spindle motor control are provided for use in a direct access storage device. A plurality of operational modes of the direct access storage device are detected. The operational modes of the direct access storage device include start-up and idle operational modes and predetermined critical operational modes that include reading of data and reading of servo information. A pulse width modulation (PWM) mode control for applying driving current to the spindle motor is provided responsive to detecting a start-up or an idle operational mode. A linear mode control for applying driving current to the spindle motor is provided responsive to detecting one of the predetermined critical operational modes. During operation of the disk file, a small percentage of the overall file power-on time is spent performing critical file operations so that substantial power savings are achieved by the PWM mode control.
    Type: Grant
    Filed: August 18, 1992
    Date of Patent: February 22, 1994
    Assignee: International Business Machines Corporation
    Inventors: Kevin J. Erickson, Richard Greenberg, Douglas W. Nelson
  • Patent number: 5276848
    Abstract: A multilevel cache buffer for a multiprocessor system in which each processor has a level one cache storage unit which interfaces with a level two cache unit and main storage unit shared by all processors. The multiprocessors share the level two cache according to a priority algorithm. When data in the level two cache is updated, corresponding data in level one caches is invalidated until it is updated.
    Type: Grant
    Filed: August 20, 1991
    Date of Patent: January 4, 1994
    Assignee: International Business Machines Corporation
    Inventors: Patrick W. Gallagher, Steven L. Gregor, Stephen M. Reeve
  • Patent number: 5265244
    Abstract: A data access structure facilitates the processing of statistical queries concerning records stored in the structure. The structure, according to the present invention, includes a plurality of data nodes storing the records, and a plurality of access nodes, each storing at least one pointer to another access node or to a data node, and arranged according to an organization whereby each access node is linked directly or indirectly to at least one data node. Statistical information is stored in or linked to the nodes of a subset of the plurality of access nodes and data nodes. The statistical information concerns the records stored in the data node or data nodes linked directly or indirectly to the respective nodes of the subset. Further, a software algorithm is provided responsive to changes in the records stored in the data nodes for updating the statistical information in the access structure concerning the records stored in the data node.
    Type: Grant
    Filed: June 22, 1990
    Date of Patent: November 23, 1993
    Assignee: International Business Machines Corporation
    Inventors: Sakti P. Ghosh, Raymond A. C. Lorie
  • Patent number: 5202940
    Abstract: The electrical/optical modular coupler enables terminal units coupled to it to be interconnected over the optical and/or electrical bus by which they are physically intercoupled.
    Type: Grant
    Filed: February 6, 1992
    Date of Patent: April 13, 1993
    Assignee: International Business Machines Corporation
    Inventor: Robert Betts
  • Patent number: 5202972
    Abstract: A multiprocessor computer system has a common master storage and data/instruction caches for each processor. Separate buffer storage units for each processor read data from the processor in parallel with the caches, but write data to the master storage sequentially, as directed by a controller for the master storage.
    Type: Grant
    Filed: July 3, 1991
    Date of Patent: April 13, 1993
    Assignee: International Business Machines Corporation
    Inventors: Richard J. Gusefski, Chon I. Lei, Alfonso Ramirez
  • Patent number: 5203007
    Abstract: In a computer system, programmable priority as well as selective blocking in order to make selection between instructions and commands which require the use of common resources.
    Type: Grant
    Filed: October 3, 1991
    Date of Patent: April 13, 1993
    Assignee: International Business Machines Corporation
    Inventor: Patrick W. Gallagher
  • Patent number: 5201041
    Abstract: An inpage buffer is used between a cache and slower storage device. When a processor requests data, the cache is checked to see if the data is already in the cache. If not, a request for the data is sent to the slower storage device. The buffer receives the data from the slower storage device and provides the data to the processor that requested the data. The buffer then provides the data to the cache for storage provided that the cache is not working on a separate storage request from the processor. The data will be written into the cache from the buffer when the cache is free from such requests. The buffer is also able to provide data corresponding to subsequent requests provided it contains such data. This may happen if a request for the same data occurs, and the buffer has not yet written the data into the cache. It can also occur if the areas of the cache which can hold data from an area of the slower storage is inoperable for some reason.
    Type: Grant
    Filed: February 25, 1991
    Date of Patent: April 6, 1993
    Assignee: International Business Machines Corporation
    Inventors: James E. Bohner, Thang T. Do, Richard J. Gusefski, Kevin C. Huang, Chon I. Lei
  • Patent number: 5157765
    Abstract: A rasterizer 10 for converting a datastream 12 which describes a page to be printed into a rasterized pagemap bitstream 13 to be sent to a printer. The rasterization is done in four stages using parallel processors in all stages except the first, and pipelining the processors between all of the stages. In the first stage 11, a scan processor 14 identifies and stores state-independent blocks 14 in the datastream. In the second stage 17, parallel block processors 22 convert the scanned blocks into stored intermediate-form data objects 20 and request preparation of often-used resources such as characters. In the third stage 23, the objects are sorted and stored by geographical region of the pagemap by parallel sort processors 24. In the fourth stage 31, the sorted objects are rasterized into pelmaps and placed in the pagemap by parallel bin processors 30. All four stages are pipelined.
    Type: Grant
    Filed: January 3, 1992
    Date of Patent: October 20, 1992
    Assignee: International Business Machines Corporation
    Inventors: Yitzhak Birk, James M. McCrossin
  • Patent number: 5155678
    Abstract: A method for maintaining switchover between a backup and degrading active processor, which switchover is transparent to a terminal accessing the active processor with atomic transactions. The backup processor prepares for an outage by the active processor by synchronizing, tracking, and monitoring the active processor's log entries. When the active processor fails, the backup processor performs the necessary recovery processing and takes over user-transactions processing as the new active processor.
    Type: Grant
    Filed: October 29, 1985
    Date of Patent: October 13, 1992
    Assignee: International Business Machines Corporation
    Inventors: Takeshi Fukumoto, Takayuki Funahasi, Harrison Scofield, Terrence E. Walker, James W. Young, Jr.
  • Patent number: 5133068
    Abstract: An implementation of referential integrity in which descriptions of referential constraints are compiled into meta-data descriptions of the constraint rules and specifications. The meta-data descriptions of the constraints are stored in the form of objects called relationship descriptors. Each relationship descriptor contains a complete description of a referential constraint, either directly or by means of pointers to other objects such as record and index descriptors which contain information comprised in the constraint's specification. The relationship descriptors are linked into two types of chains by symbolic pointers. One type of relationship descriptor chain connects all relationship descriptors which have a common parent table. The other type of relationship descriptor chain connects relationship descriptors with common dependent tables. Both types of chains are anchored in respective fields in the tables' record descriptors.
    Type: Grant
    Filed: August 28, 1991
    Date of Patent: July 21, 1992
    Assignee: International Business Machines Corporation
    Inventors: Richard A. Crus, Michael J. Dockter, Robert W. Engles, Donald J. Haderle
  • Patent number: 5093912
    Abstract: A method for expanding and contracting a resource pool dynamically, i.e. in response to demand for the resources, is disclosed. Resources are allocated for use from a single master pool 22. The overall pool of available resources is expanded by creating an extension pool and adding its resources to the master pool. The master pool can theoretically be expanded to the limits of the number of resources available in the system.To contract the pool dynamically, first one of the extension pools is selected to be freed (FREE.sub.-- POOL 66). Those resources owned by the freed pool but still in the master pool (i.e., not in use) are moved to the extension pool, preventing their reuse. Resources in use which are owned by the freed pool are labeled by changing their home address 52 so that they will be returned to the extension pool instead of to the master pool. Once all such resources have been returned to the freed extension pool it is deleted, thereby contracting the overall pool of resources.
    Type: Grant
    Filed: June 26, 1989
    Date of Patent: March 3, 1992
    Assignee: International Business Machines Corporation
    Inventors: Margaret A. Dong, Richard K. Treiber
  • Patent number: 5043872
    Abstract: This invention measures the degree of clustering of an index for a relational data base table, estimates the number of physical page accesses required to access the table using a partial index scan using the index, and selects the index providing the fastest access path to the table. The degree of clustering is measured as follows:DC=Number of clustered rows (NCR)/Total rows (NR)A multiplier greater than 1 can be applied to the degree of clustering to reflect the benefit of having consecutively accessed rows on adjacent or nearby data pages.The degree of clustering so calculated is used to estimate the number of random and sequential page accesses required for a partial index scan. These numbers of accesses are then multiplied by the unit time required for each, and added to the total CPU processing time required to arrive at the estimated total time for the scan.
    Type: Grant
    Filed: July 15, 1988
    Date of Patent: August 27, 1991
    Assignee: International Business Machines Corporation
    Inventors: Josephine M. Cheng, Akira Shibamiya, Yun Wang
  • Patent number: 4961134
    Abstract: A page-accessing method in a segmented tablespace 10 which eliminates unnecessary reading and locking. The tablespace comprises data pages 18 grouped into identically-sized segments 16, each segment storing data for a single table. A status indicator 26 for each data page of a segment is kept in a separate segment control block 20 stored on a space map page 14. Five data page status indicator values are maintained:(1) FULL (26a) - entirely full of current data;(2) PARTIALLY FULL (26b) - partially full of current data;(3) UNFORMATTED (26c) - empty; contains no data;(4) MASS DELETE (26d) - contains only obsolete data because of an unqualified deletion (mass delete) of data; or(5) QUALIFIED DELETE (26e) - contains only obsolete data because of a qualified deletion of data.When scanning over the data in a segment, UNFORMATTED and MASS DELETE pages are skipped. QUALIFIED DELETE pages are locked, and then skipped if they still contain only obsolete data when the lock is obtained.
    Type: Grant
    Filed: July 15, 1988
    Date of Patent: October 2, 1990
    Assignee: International Business Machines Corporation
    Inventors: Richard A. Crus, Donald J. Haderle, James Z. Teng
  • Patent number: 4956774
    Abstract: A method for more accurately estimating the time required to process a data base query using a selected index. A selected number of the most frequently occurring index key values (38) are collected during an index sequential scan. These most frequency occurring values are stored as percentage frequencies of occurrence in the data base system's catalog (42). Estimated access and processing times (NPAR, NPAS, NCPU) for a given query are calculated based on the stored frequencies where possible. Where the query's search criteria specify values other than the stored most frequently occurring values, those values are assumed to be uniformly distributed.
    Type: Grant
    Filed: September 2, 1988
    Date of Patent: September 11, 1990
    Assignee: International Business Machines Corporation
    Inventors: Akira Shibamiya, Melvin R. Zimowski