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:
Mar. 16, 2010
Filed:
Feb. 05, 2007
Applicants:
Toshiya Seki, Odawara, JP;
Eiju Katsuragi, Odawara, JP;
Takashi Sakaguchi, Odawara, JP;
Inventors:
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06F 7/00 (2006.01); G06F 12/00 (2006.01);
U.S. Cl.
CPC ...
Abstract
A storage control technique with which, even if not data, but only its management information is deleted, a host system can recognize storage areas storing unnecessary data and so use them effectively. When a file system in the host system deletes the management information for data stored in a page in a pool volume, a control circuit writes '0' in all the areas in the deletion target page in response to a command from the host system. The control circuit then detects the page where '0' is written in all of its areas and releases it from allocation to the corresponding virtual volume.