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:
Aug. 12, 2008
Filed:
Mar. 31, 2005
Tetsuya Uemura, Saitama, JP;
Tetsuya Uemura, Saitama, JP;
Hitachi Global Storage Technologies Netherlands B.V., Amsterdam, NL;
Abstract
Embodiments of the invention achieve data write in an appending manner by conversion from a logical block address to a physical block address in a HDD that has only one storage device and does not have a large-scale cache memory. In one embodiment, a check is made as to whether or not the size of an address translation table in a cache memory exceeds a threshold value. If the size exceeds the threshold value, entries whose number is specified are selected by the LRU method. The selected entries are added to a WRITE buffer, and the address translation table is saved on the HDD by executing WRITE. Seek time of a head at the time of WRITE is reduced, thereby improving WRITE performance. There is produced an effect of building such a snapshot that while a usual access to a HDD volume is allowed, it is possible to make an access to a volume of the snapshot which is a past state of the HDD. Disabling write after writing to the HDD is disabled. Thus, it possible to roll back to a HDD state at an arbitrary point of time.