I think time spent in each type of I/O operation is the best way to profile usage patterns in this context.
good point, i agree

Is it just counting the number of I/O operations of each type and computing a percentage?
i think. i am wondering how they came to that as well. when he gets back from CES i will shoot him a pm and see. you make excellent points, thats what i was looking for, varied viewpoints on it