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:
Apr. 14, 1987
Filed:
Nov. 18, 1983
Kenichi Shiozaki, Odawara, JP;
Makoto Kishi, Ashigarakamigun, JP;
Tomoatsu Yanagita, Machida, JP;
Kanji Kubo, Hadano, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Change bits are provided in correspondence with storage information units (blocks or pages) of a storage, and indicate whether or not a 'store' operation has been performed into the corresponding storage information units. The change bits are retained in a first retention device in correspondence with the storage information units, and a copy of the change bits in the first retention device is retained in a second retention device. When the store operation is performed to effect a storing of data into the storage, a control device refers to the change bit retained by the second retention device and controls updating of the change bit of the first retention device in accordance with the indication of the change bit referred to.