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:
Nov. 20, 2001
Filed:
Jan. 25, 1999
Walter A. Hubis, Louisville, CO (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for providing cache coherency in a RAID system in which multiple RAID controllers provide read/write access to shared storage devices for multiple host computers. Each controller includes read, write and write mirror caches and the controllers and the shared storage devices are coupled to one another via common backend busses. Whenever a controller receives a write command from a host the controller writes the data to the shared devices, its write cache and the write mirror caches of the other controllers. Whenever a controller receives a read command from a host the controller attempts to return the requested data from its write mirror cache, write cache and read cache and the storage devices, in that order.