Sughrue, Mion, Zinn, Macpeak & Seas, PLLC
Method and apparatus of controlling a disk cache during a degenerated mode of operation
 A disk cache is controlled to continue duel data writing even during a degenerated mode of operation due to a failure of a cache memory, and also to continue a FAST WRITE process while maintaining reliability for thereby avoiding a drop in performance. If a memory module MM#1 fails, processing of dirty data 111 stored in the memory module MM#1 is continued using backup data 122 stored in a memory module MM#2 for the dirty data 111 stored in the memory module MM#1. The backup data 122 stored in the memory module MM#2 for the dirty data 111 stored in the memory module MM#1 is copied to a memory module MM#3, generating backup data 111' for the dirty data 111. Then, dirty data 131 stored in the memory module MM#3 is copied to the memory module MM#2, generating backup data 112' for the dirty data 131 stored in the memory module MM#3, instead of backup data 112 stored in the memory module MM#1. 
NEC Corporation
G G G
G06F G06F G06F
additional inventional inventional
Yoshiaki
Mori