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:
Sep. 03, 1996
Filed:
Apr. 16, 1993
Tetsuhiko Fujii, Kawasaki, JP;
Akira Yamamoto, Sagamihara, JP;
Tetsuzo Kobashi, Odawara, JP;
Masahiko Sato, Odawara, JP;
Takao Satoh, Sagamihara, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A disk subsystem provided with a cache has a capability of executing writing of data of discontinuous dirty blocks on a cache memory into a disk and reading of data of discontinuous empty blocks on the cache memory through the effect of just one DMA transfer. When the dirty data discontinuously ranged on a cache segment is written on the disk, the microprocessor provides a bit-map to a harddisk controller (HDC) as control information for data transfer. If an i-th bit of the bit-map is '1', the HDC operates to write the i-th block data sent from a direct memory access controller (DMAC) onto the corresponding sector of the disk. If the i-th bit is '0', the microprocessor serves to stop the write of the data and control a read/write head to wait until it passes the corresponding sector.