Patent ID: 6665739
Filing Date: 2003-12-16
Classification: G06F

Abstract:
A method for responding to an input-output request from a host to effect a transfer to a specified location within a logical volume in a disk array storage device wherein a host operating system utilizes a first, uniquely identified, base unit control block corresponding to the logical volume to effect a transfer in response to the input-output request, said method enabling the host to send overlapped input-output requests to the logical volume and comprising the steps of:A) within the host i) defining at least one related, uniquely identified unit control block that identifies the logical volume including the establishment of a parallel access control block for each unit control block associated with the logical volume and a parallel access main control block for the logical volume through which each of the base and related unit control blocks can be identified, ii) interrupting the operating system response to the input-output request by assigning one of the base and related unit control blocks to the input-output request, and iii) returning control of the response to the input-output request to the operating system identifying the assigned unit control block whereby the host operating system can issue overlapped input-output requests to the given logical volume, and B) within the disk array storage facility i) establishing a table for the logical volume with entry input-output requests and corresponding parameters, and ii) testing the parameters for each new input-output request to the logical volume with respect to the parameters for input-output request entries in the table to determine which, of a plurality of control functions including enabling the processing of the input-output request by the storage facility, will be performed.