Operating system for generating overlapped input-output requests to a device in a disk array storage
AssigneeEMC Corporation
InventorsWilliam R. Fairchild, Douglas E. LeCrone, Daniel A. Murphy
Life of this patent
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Abstract
A method for enabling a data processing system with a host running under an operating system and with a disk array storage device organized by logical devices to process panel I/O requests to a logical device from one or more host processors concurrently. The system includes a parallel access control block that identifies unit control blocks assigned to the same logical device. If an I/O request is received while a main UCB unit is busy, the main control block identifies another unit control block to enable an overlapped access to the logical device.
Claims24
A method for responding to an input-output request from a host to effect a transfer with 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 comprising the steps of:
- A) defining at least one uniquely identified related unit control block that identifies the logical volume and a parallel access main control block through which each of the base and related control blocks can be identified,
- B) interrupting the operating system response to the input-output request,
- C) assigning one of the base and related unit control blocks to the input-output request, and
- D) returning control of the response to the input-output request to the operating system identifying the assigned control block whereby the host operating system can issue overlapped input-output requests to the given logical volume.
A system 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 system comprising:
- A) a pool of at least one uniquely identified related unit control block wherein each related unit control block identifies the logical volume,
- B) a parallel access main control block for the logical volume that enables the location of each of the base and related control blocks to be identified,
- C) a first module for interrupting the operating system response to each input-output request identifying the logical volume,
- D) a second module for assigning one of the base and related unit control blocks to the input-output request, and
- E) a third module for returning control of the response to the input-output request to the operating system identifying the assigned control block whereby the host operating system can issue overlapped input-output requests to the given logical volume.
Dependencies are inferred from the claim text.