Fujitsu Corporation

Yuichi Hirao

Hideaki Tanaka

Aaron Keith Olbrich

Douglas Alan Prins

Shigeru Shimizu

Tatsuya Haga

Hiroaki Murai

Koji Yoneyama

Noriyuki Sato

Masami Aihara

Masaki Obuchi

Mitsuhiko Sugiyama

Shigeru Hatakeyama

Takumi Kakuya

A disk storage device stores write data in a cache area of a data buffer according to a write command from a host, reports write completion to the host, and then writes the write data in the cache area to a storage medium. The disk storage device stores the write data stored in the data buffer in a save area created on the storage disk in response to the reception of a command which requires integrity, other than a write command, and reports a response to the host. Therefore processing time of this command and response time to the host can be decreased, while maintaining the safety of the write data.

Disk storage device and cache control method for disk storage device

Methods for controlling and storing data in a cache buffer in a storage apparatus having a nonvolatile memory medium are disclosed. Memory cells are logically divided into a plurality of pages. An open status is registered in a counter for each page that has at least some (and usually all) memory cells available to store new data. A full status is registered in the counter for each page that does not have memory cells that are available to store new data. New data is stored in pages having the open status in the counter. The pages can be weighted according to the read command rate and prioritized for reading and writing purposes.

Cache buffer control apparatus and method using counters to determine status of cache buffer memory cells for writing and reading data therefrom

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Kawasaki, Japan

Yuichi Hirao