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. 24, 2019
Filed:
Apr. 08, 2015
Hitachi, Ltd., Tokyo, JP;
Kazutomo Ushijima, Tokyo, JP;
Akira Yamamoto, Tokyo, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A blockwise-erase nonvolatile storage device for storing a database includes extended logical-to-physical conversion information that associates, for each of a plurality of logical addresses, a timestamp, a physical address, and a reference counter with each other. Each reference counter indicates the number of referring sources to refer to data associated with both the logical address and the timestamp that are associated with the reference counter. On the basis of the conversion information, it is determined whether a target logical address has associated therewith a timestamp older than the latest timestamp and whether the reference counter associated with both the target logical address and the older timestamp indicates that there is no referring source. If so, then the blockwise-erase nonvolatile storage device manages, as an erasable physical area (invalid physical area), the physical area at the physical address associated with both the target logical address and the older timestamp.