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:
Jun. 22, 1999
Filed:
Dec. 15, 1995
Ashwath Nagaraj, Fremont, CA (US);
Ashok Bhaskar, Fremont, CA (US);
Mylex Corporation, Fremont, CA (US);
Abstract
A RAID (3, 4, or 5) disk array memory system incorporates a method and apparatus for the management of faulty data that eliminates the unintentional creation of spurious data when a double fault occurs. For example, when a disk drive failure occurs in one channel and the failed disk is replaced, reconstruction of the data can be achieved because a parity drive channel is provided for correcting errors. If a read error occurs during reconstruction of the failed disk data, the block corresponding to the error block does not allow the reconstruction of the corresponding failed disk block. To prevent the misuse of the two data blocks, a bad data table (BDT) is constructed that lists the addresses of the block just read and the block to be reconstructed. Also a standard filler block is written into the two bad blocks and a new parity block is created. The addresses of all access requests to the memory array are compared with the BDT and, if not listed, the access proceeds. If an address is listed, an error signal is returned. For a listed write request, the bad block address is deleted from the BDT, new data written into the block and a new parity block computed and stored.