External storage subsystem

This patent is subject to a terminal disclaimer.

(21) Appl. No.: 10/614,860

(22) Filed: Jul. 9, 2003

(65) Prior Publication Data

US 2004/0010639 Al Jan. 15, 2004

Related U.S. Application Data

(63) Continuation of application No. 09/819,636, filed on Mar. 29, 2001, now Pat. No. 6,745,261, which is a continuation of application No. 09/379,635, filed on Aug. 24, 1999, now abandoned, which is a division of application No. 08/902, 362, filed on Jul. 29, 1987, now Pat. No. 5,951,655, which is a continuation of application No. 08/502,045, filed on Jul. 13, 1995, now Pat. No. 5,689,729, which is a continuation of application No. 07/984,763, filed on Dec. 3, 1992, now Pat. No. 5,459,856.

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(Continued)

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Japanese language Office Action dated Jan. 4, 2005. English Translation of Japanese Office Action No. 2003-156485, dated Mar. 25, 2005 and Office Action of Japanese Patent Application No. 2003-156486, dated Mar. 25, 2005 and Office Action of Japanese Patent Application No. 2003-156486.

(Continued)

Primary Examiner—Jeffrey Gaffin Assistant Examiner—Alan S. Chen (74) Attorney, Agent, or Firm—Kenyon & Kenyon LLP

(57) ABSTRACT

A plurality of independent cache units and nonvolatile memory units are provided in a disk controller located between a host (central processing unit) and a magnetic disk drive. A plurality of channel units for controlling the data transfer to and from the central processing unit and a plurality of control units for controlling the data transfer to and from the magnetic disk drive are independently connected to the cache units and the nonvolatile memory units through data buses and access lines.

14 Claims, 6 Drawing Sheets

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English Translation of Japanese Office Action No.

2003-156486, dated Mar. 25, 2005 and Office Action of

Japanese Patent Application No. 2003-156486.

English Translation of Japanese Office Action No.

2003-189152, dated Mar. 25, 2005 and Office Action of

Japanese Patent Application No. 2003-189152.

Partial Translation of Japanese Office Action No. 3-322965

dated Apr. 1, 2003 and Japanese Office Action No. 3-322965

of Apr. 1, 2003.

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* cited by examiner