Emulex Corporatioln

Jennifer Sullivan

Peter Mark Fiacco

Vi Chau

A method and apparatus for establishing a large number of EDTOV timers, each determining when an event has failed to occur on an exchange of a communications protocol. Values for each timer are maintained as a timer array. The entire timer array is read at regular scan intervals by a state machine and decremented by four associated hardware decrementers, four timers at one time. A Scan Interval variable determines the scan interval. The present invention is capable of scan intervals of up to 100 ns. Active time values are read, checked for zero, decremented preferably by one, and written back to the timer array. If a timer is detected as having timed out (equal to zero), then a value which identifies the exchange associated with that timer is logged into a time-out FIFO and 'FF'h is written back into the timer. At the heart of the invention is the efficient use of dedicated hardware to decrement or otherwise alter the values of each timer as appropriate, and the use of a dedicated state machine to read values for each timer, provide the value to the hardware, and then load the new value of each timer back into memory.

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Huntington Beach, CA, United States of America

Jennifer Sullivan