Rakesh D Barve

US Patent:

62601083, Jul 10, 2001

Filed:

Jul 2, 1998

Appl. No.:

9/110114

Inventors:

Rakesh D. Barve - Durham NC
Phillio B. Gibbons - Westfield NJ
Bruce K. Hillyer - Lebanon NJ
Yossi Matias - Potomac MD
Elizabeth Shriver - Jersey City NJ
Jeffrey S. Vitter - Durham NC

Assignee:

Lucent Technologies, Inc. - NJ

International Classification:

G06F 1200

US Classification:

711112

Abstract:

A method for estimating and read durations, in response to requests to read data blocks stored in the disk drives in a computer system having a plurality of disk drives. Each disk drive has a disk cache with a non-zero fence parameter value coupled to a host computer via a common bus. The method according to one embodiment, comprises the steps of: (a) measuring an overhead period corresponding to the time during which a request to read is transmitted to a disk drive via the bus; (b) measuring an expected minimum positioning time corresponding to the shortest time required for a disk drive to locate said data block; (c) measuring mechanism-to-cache read time corresponding to the time required for a disk drive to transfer a data portion B. sub. C to a disk cache; (d) measuring the time required to transfer data blocks stored in each of said disk caches to the host; and (e) adding the times measured at steps (a) through (d).

US Patent:

63016400, Oct 9, 2001

Filed:

Jul 2, 1998

Appl. No.:

9/110110

Inventors:

Rakesh D. Barve - Durham NC
Phillip B. Gibbons - Westfield NJ
Bruce K. Hillyer - Lebanon NJ
Yossi Matias - Potomac MD
Elizabeth Shriver - Jersey City NJ
Jeffrey S. Vitter - Durham NC

Assignee:

Lucent Technologies, Inc. - NJ

International Classification:

G06F 1200

US Classification:

711113

Abstract:

A method for scheduling access of data blocks located in a computer system having a plurality of disk drives, each disk drive has a disk cache with a specified fence parameter value coupled to a host computer via a common bus. The method according to one embodiment, comprises the steps of: (a) sequentially accessing each of the disk drives for a predetermined number of iterations to retrieve a predetermined number of data blocks; (b) for a specified number of the iterations, transferring data located in the disk cache to be transferred to the common bus and requesting data corresponding to the following iteration to be transferred to the disk cache; and (c) repeating steps (a) and (b) until the predetermined iterations are completed.