Compaq 3200 - Manual (Page 159)

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Compaq Smart Array 3200 Controller Reference Guide
Writer: Rickard Project: Compaq Smart Array 3200 Controller Reference Guide Comments: 340862-002
File Name: L-APPE.DOC Last Saved On: 12/7/98 9:30 AM
COMPAQ CONFIDENTIAL - NEED TO KNOW REQUIRED
Concurrent I/O Request Servicing
The Smart Array 3200 Controller can service hundreds of I/O requests at a time.
For example, if you request data that resides on the first drive and another end
user requests data that resides on the second drive, the controller delivers both
pieces of information concurrently. Figure E-9 illustrates concurrent request
servicing.
User 1
Request User 2
Request User 3
Request User 4
Request
Figure E-9. Concurrent request servicing handles several I/O requests
Optimized Request Management
Optimized Request Management, also known as elevator trend sorting, is
another performance enhancement feature provided by the Smart Array 3200
Controller. The controller receives and queues multiple data requests from the
operating system. The controller then rearranges the requests in an order that
optimizes performance.
For example, the Smart Array 3200 Controller receives a request for a physical
drive that is not currently active. The controller schedules the request
immediately ahead of previously received requests already queued to other
active drives within the array. This request management process operates
concurrently with drive operations. The benefits of optimized request
management increase as greater demands are made on the drive subsystem.