The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 27, 1998
Filed:
Aug. 29, 1996
Frederick J DeWitt, Kirkland, WA (US);
Ronald O Radko, Bellevue, WA (US);
Microsoft Corporation, Redmond, WA (US);
Abstract
A method and system for caching data that improve the efficiency of a cache are provided. Generally, three types of data are stored in a cache constructed according to the principles of the present invention. These types of data include: (1) path tables, (2) directories, and (3) files. Path tables include data regarding all of the directories on a storage medium, directories include data regarding all of the subdirectories and files in each directory, and files include the actual file data. The preferred embodiment of the cache logically includes eight regions. These regions include (in order of preferred descending priority): (1) path table, (2) directory, (3) two-access, (4) zero-access or prefetch, (5) sequential-locked, (6) one-access, (7) discarded, and (8) invalid. The path table region includes sectors containing path table data, the directory region includes sectors containing directory data, the two-access region includes sectors containing file data that have been accessed twice, the prefetch region includes sectors containing file data that have been prefetched, the sequential-locked region includes sectors containing file data that were prefetched and have now been locked for access, the one-access region includes sectors containing file data that have been accessed once, the discarded region includes empty sectors that are available for reuse, and the invalid region includes a single dummy sector that is used as a placeholder. During operation, a cache manager manages the cache. The cache manager is responsible for manipulating the cache, such as by adding and removing sectors to and from the cache.