Compaq 3200 manual Concurrent I/O Request Servicing, Optimized Request Management, E-17

E-17

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	User 2	User 3	User 4
	Request	Request	Request	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.

Compaq Smart Array 3200 Controller Reference Guide