Invalidity dossier
US 6292795
Indexed file system and a method and a mechanism for accessing data records from such a system
Current assignee: International Business Machines Corp
Added 9/23/2026, 7:26:52 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 6,292,795 B1
Title: Indexed file system and a method and a mechanism for accessing data records from such a system
Assignee: International Business Machines Corporation (original assignee; current assignee listed as International Business Machines Corp)
Inventor(s): Matthew Peters; Stephen James Paul Todd
Key dates: Priority date 1998-05-30; filing date 1999-02-16; publication/grant date 2001-09-18; anticipated expiration 2019-02-16. Legal status listed as "Expired – Fee Related."
Purpose: The patent addresses access to data records in a dynamic database — one where data elements can be added and deleted so the data volume, not just data values, changes over time. The excerpt frames the problem around hashing: static hash structures needed deletion-flags, overflow bins, and frequent costly restructuring, while dynamic adaptations required expensive "rehashing" when a bin became over-full. Underestimating storage caused overflow and slow updates; overestimating wasted disk space. Very large databases and operating-system-imposed maximum hash-table sizes compounded the problem.
Plain-language scope (per the excerpt): The claimed access mechanism has a directory with entries pointing to respective indexed data files. Each indexed data file has an index containing identifiers and storage addresses of data blocks; associated logic (a) transforms an input data key into a transformed key, (b) compares it with block identifiers in the index to find a match and obtain the block address, and (c) identifies, from records in that block, data records related to the input key. The directory is preferably hierarchical (a radix tree) analyzed one bit at a time per node until a leaf node supplies a pointer to a hash table. The directory is preferably locally extensible, varying how many key bits identify a hash table.
Source: https://patents.google.com/patent/US6292795/en
What the excerpt does not establish: The full claim set, dependent-claim limitations, drawings, the complete detailed description, and the exact wording of the "locally extensible" feature (the excerpt is cut off mid-sentence). It does not list cited prior art references, prosecution history, or foreign counterparts.
Generated 10/1/2026, 9:42:04 PM
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Litigation summary
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PTAB challenges
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Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
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Obviousness
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Extensions
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Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.