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:
Dec. 20, 2011
Filed:
Sep. 30, 2004
Josef Ezra, Ashland, MA (US);
Adi Ofer, Framingham, MA (US);
Josef Ezra, Ashland, MA (US);
Adi Ofer, Framingham, MA (US);
EMC Corporation, Hopkinton, MA (US);
Abstract
Described are techniques and criteria used in connection with cache management. The cache may be organized as a plurality of memory banks in which each memory bank includes a plurality of slots. Each memory bank has an associated control slot that includes groups of extents of tags. Each cache slot has a corresponding tag that includes a bit value indicating the availability of the associated cache slot, and a time stamp indicating the last time the data in the slot was used. The cache may be shared by multiple processors. Exclusive access of the cache slots is implemented using an atomic compare and swap instruction. The time stamp of slots in the cache may be adjusted to indicate ages of slots affecting the amount of time a particular portion of data remains in the cache. Each director may obtain a cache slot from a private stack of nondata cache slots in addition to accessing a shared cache used by all directors.