System for scheduling read ahead operations if new request is sequential of last n last read requests wherein n is different on independent activities

Claim 1

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request sequentially follows any of the addresses of the last plurality n disk read requests; scheduling a readahead operation when the disk read request sequentially follows an address of the last plurality n disk read requests; determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and performing the readahead operation by reading a block of data having the readahead length.

Claim 2

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request sequentially follows any of the addresses of the last plurality n disk read requests; scheduling a readahead operation when the disk read request sequentially follows an address of the last plurality n disk read requests; determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and performing the readahead operation by reading a block of data having the readahead length.

Claim 3

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request sequentially follows any of the addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request sequentially following an address of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.

Claim 4

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request sequentially follows any of the addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request sequentially following an address of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.

Claim 5

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request follows in a pattern with respect to addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request following in a pattern with respect to an address of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.

Claim 6

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request follows in a pattern with respect to addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request following in a pattern with respect to an address of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.

Claim 7

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: tracking the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request is adjacent to any address of the addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request that is adjacent to an address of the addresses of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.

Claim 8

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: tracking the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request is adjacent to any address of the addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request that is adjacent to an address of the addresses of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.

Claim 9

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request is in proximity to any of the addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request in proximity to an address of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.

Claim 10

A method of operating one or more disk drives through a disk drive controller which is interfaced through a bus to a host computer, wherein the disk drive controller receives read requests from the host computer, each read request specifying one or more data read addresses, the method comprising the controller-executed steps of: monitoring the read addresses of the last plurality of n disk read requests, where n is a programmable parameter having a value of n set as a function of the number of independent activities executing within the host computer; determining whether the address of a disk read request is in proximity to any of the addresses of the last plurality of n disk read requests; and performing a readahead operation operable for a disk read request in proximity to an address of the last plurality of n disk read requests, the readahead operation including the steps of: determining a data read length specified by the disk read request; deriving a readahead length which is a multiple of the determined data read length; and reading a block of data specified by the address of the disk read request and the readahead length.