Emc Corporation

Daniel P Murphy

Douglas Eric LeCrone

William R Fairchild

Natan Vishlitzky

Hana Moreshet

Martin Farley

Izhar Sharon

Elizabeth E Patapoutian

A method and system for optimizing input-output requests. Input-output requests are intercepted before any information transfers to a data storage facility. Commands in the input-output request are scanned to determine their starting and ending addresses. The scanned addresses are then converted into an address extent that is coextensive with all the starting and ending addresses associated with commands for transferring data to the data storage facility. That address extent is transferred to the data storage facility and may incorporate fewer addresses than are present in an initial address extent.

Method for optimizing multiple input/output requests to a single logical device

A method for enabling overlapped input/output requests to a logical device using assigned and parallel access unit control blocks. Each I/O request interrupts an operating system to assign a base and related unit control block to the input/output requests. In addition a parallel access control block is associated with each unit control block for a logical volume and a parallel access main control block is established with a logical volume through which each of the base and related unit control block can be identified. An input/output request to a logical device interrupts the operating system to assign one of the base and one of the assigned unit control blocks to the input/output requests after which control transfers back to the operating system. At a disk storage facility, the input/output request is located in a table with other input/output requests and corresponding parameters. The disk array storage facility tests the parameters for each new input/output request to determine which of a plurality of control functions will be performed.

Method for enabling overlapped input/output requests to a logical device using assigned and parallel access unit control blocks

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Hopkinton, MA, United States of America

Daniel P Murphy