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David Levish Phones & Addresses

  • 6137 Corte Del Conejo, San Jose, CA 95120

Publications

Us Patents

Method, System, And Program For Reverse Index Scanning

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US Patent:
6647386, Nov 11, 2003
Filed:
Dec 14, 2000
Appl. No.:
09/736608
Inventors:
Christina Marie Lee - San Jose CA
David L. Levish - San Jose CA
Michael R. Shadduck - Los Altos CA
Yufen Wang - Saratoga CA
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 1730
US Classification:
707 8, 707 3
Abstract:
Provided is a system, method, and program for performing a reverse scan of an index implemented as a tree of pages. Each leaf page includes one or more ordered index keys and previous and next pointers to the previous and next pages, respectively. The scan is searching for keys in the leaf pages that satisfy the search criteria. If a current index key is a first key on a current page, then a request is made for a conditional shared latch on a previous page prior to the current page. If the requested conditional shared latch is not granted, then the latch on the current page is released and a request is made for unconditional latches on the previous page and the current page. After receiving the latches on the previous and current pages, a determination is made of whether the current index key is on the current page if the current page was modified since the unconditional latch was requested. The current index key is located on the current page if the current index key is on the current page. A determination is then made of whether the located current index key satisfies the search criteria.

Method, System And Program For Scrolling Index Scans

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US Patent:
6654039, Nov 25, 2003
Filed:
Oct 13, 2000
Appl. No.:
09/687856
Inventors:
Christina Marie Lee - San Jose CA
David L. Levish - San Jose CA
San Yu Phoenix - Morgan Hill CA
Michael R. Shadduck - Los Altos CA
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 300
US Classification:
345830, 345968, 345823, 345860, 345784, 715503, 707 3
Abstract:
A method, system and program for accessing records in a database object, such as an index or table. A cursor is maintained that points to a start entry in the database object. The database object has rows and columns of values. A runtime component receives a command to return a kth entry in the object having column values that satisfy predicates in a query statement. The runtime component calls a manager component that accesses entries in the database object to return the kth entry in the object having column values that satisfy the predicates. The manager component moves the cursor through sequential entries in the database object, in either the forward or reverse direction, until a kth entry that satisfies the predicates from the start entry is reached. The manager component positions the cursor to an entry that is the kth entry that satisfies the predicates from the start entry and returns data from the kth entry pointed to by the cursor to the runtime component.

System And Method For Performing Dynamic Buffer Management In An Hfs (Hierarchical File System Df/Sms)

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US Patent:
6718445, Apr 6, 2004
Filed:
Mar 26, 1999
Appl. No.:
09/280796
Inventors:
Cecilia Carranza Lewis - San Jose CA
Jeffrey Allen Berger - San Jose CA
David Levish - San Jose CA
W. James Kincaid - Pebble Beach CA
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 1200
US Classification:
711159, 711170, 710 56
Abstract:
The present invention provides a system and method for dynamic management of buffers by the buffer manager for a hierarchical file system. A system according to the present invention includes a buffer pool which is comprised of both fixed and virtual storage. The buffer pool is logically partitioned into three states, fixed, pageable and released, wherein each of the plurality of buffers in the buffer pool exists in one of these states. The system further comprises the buffer manager, which dynamically manages the buffers in the system by moving them between these three states in a non-disruptive manner based on a comparison between the actual usage of fixed and virtual storage compared with target usage values for the fixed and virtual storage.

Dynamically Switching The Serialization Method Of A Data Structure

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US Patent:
8484235, Jul 9, 2013
Filed:
Mar 28, 2011
Appl. No.:
13/072953
Inventors:
Stephanie Hui-An Lee - Saratoga CA,
David L. Levish - San Jose CA,
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 17/30
US Classification:
707760, 710769
Abstract:
Embodiments of the invention comprise a method for dynamically switching a serialization method of a data structure. If use of the serialization mechanism is desired, an instruction to obtain the serialization mechanism is received. If use of the serialization mechanism is not desired and if the serialization mechanism is in use, an instruction to obtain the serialization mechanism is received. If use of the serialization mechanism is not desired and if the serialization mechanism is not in use, an instruction to access the data structure without obtaining the serialization mechanism is received.

Dynamically Switching The Serialization Method Of A Data Structure

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US Patent:
8538977, Sep 17, 2013
Filed:
Mar 5, 2012
Appl. No.:
13/412021
Inventors:
Stephanie Hui-An Lee - Saratoga CA,
David L. Levish - San Jose CA,
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 17/30
US Classification:
707760, 710769
Abstract:
Embodiments of the invention comprise a method for dynamically switching a serialization method of a data structure. If use of the serialization mechanism is desired, an instruction to obtain the serialization mechanism is received. If use of the serialization mechanism is not desired and if the serialization mechanism is in use, an instruction to obtain the serialization mechanism is received. If use of the serialization mechanism is not desired and if the serialization mechanism is not in use, an instruction to access the data structure without obtaining the serialization mechanism is received.

Creating And Maintaining Order Of A Log Stream Without Use Of A Lock Or Latch

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US Patent:
20120096055, Apr 19, 2012
Filed:
Oct 13, 2010
Appl. No.:
12/904026
Inventors:
Stephanie H. Lee - Saratoga CA,
David L. Levish - San Jose CA,
Ronald E. Parrish - Santa Cruz CA,
Assignee:
INTERNATIONAL BUSINESS MACHINES CORPORATION - Armonk NY
International Classification:
G06F 17/30
US Classification:
707822, 707E17009
Abstract:
Provided are techniques for using a series of compare and swap operations to assign a Relative Byte Address (RBA) and a Logical Record Sequence Number (LRSN) to a log record. One or more log buffers for storing the log record are identified, and the log record is moved to the one or more log buffers.

Creating And Maintaining Order Of A Log Stream Without Use Of A Lock Or Latch

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US Patent:
20120203805, Aug 9, 2012
Filed:
Apr 18, 2012
Appl. No.:
13/450337
Inventors:
Stephanie H. Lee - Saratoga CA,
David L. Levish - San Jose CA,
Ronald E. Parrish - Santa Cruz CA,
Assignee:
INTERNATIONAL BUSINESS MACHINES CORPORATION - Armonk NY
International Classification:
G06F 17/30
US Classification:
707822, 707E1701
Abstract:
Provided are techniques for using a series of compare and swap operations to assign a Relative Byte Address (RBA) and a Logical Record Sequence Number (LRSN) to a log record. One or more log buffers for storing the log record are identified, and the log record is moved to the one or more log buffers.

Method And Apparatus For Shadowing A Hierarchical File System Index Structure To Enable Error Recovery

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US Patent:
61923761, Feb 20, 2001
Filed:
Nov 13, 1998
Appl. No.:
9/191172
Inventors:
W. James Kincaid - Pebble Beach CA
David Levish - San Jose CA
Thomas A. Mahon - San Jose CA
Assignee:
International Business Machines Corporation - Armonk NY
International Classification:
G06F 1730
US Classification:
707202
Abstract:
The method of the invention updates a tree arranged index for an hierarchical file system (HFS). The index includes at least one index value, i. e. , an index page, that is logically positioned between an index anchor value and a sequence page. The sequence page includes actual index data. Logical positioning of the index page is determined by one or more pointers. The method initially responds to an index update request by making an update "shadow" copy of (i) a sequence page and (ii) any other index pages, up to and including a root page, that are to be updated in accord with the update request. Thereafter, an index manager updates the shadow copy of the sequence page in accord with the update request. The index manager further updates the root page and each shadowed index page that is present in a path to the updated sequence page to indicate that the path has been updated and includes the most current data. If a cancel or error indication occurs prior to updating of the index path, the shadowed copies of the sequence page, index page and root page are released, enabling the system to return to the non-updated pages.
David L Levish from San Jose, CA, age ~62 Get Report