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:
May. 05, 1998
Filed:
Jun. 15, 1993
Sadasaburo Kanai, Kawasaki, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
In a cache controller having a cache disposed between a CPU and a direct access storage for temporarily storing therein data transferred between the CPU and the storage, data is written from the cache into the storage in a write after mode. There is employed an update generation identifier specified by the CPU at each predetermined point of time. When storing data (write after data) from the cache into the storage in the write after mode, the last update generation specified prior to when the data is first written in the cache is set as the update generation of the data. When an update generation is specified by the CPU, write after data having a generation older than the specified generation by a predetermined effective management generation number n or more is preferentially written in the storage. When write after data is lost in the cache due to a failure during execution of a program, old data is read from the storage to execute again the program beginning from a point thereof corresponding to the oldest update generation of write after data, thereby recovering the lost write after data. Alternatively, the write after data is recovered by use of the update journals beginning from a point thereof associated with the oldest update generation.