Problem
A disk rotates at a rate of 7200 revolutions per minute. After the access heads arrives at a desired track, it takes an average of one half revolution of the disk to get to the beginning of a requested sector. Each track contains 128 sectors and each sector contains 512 bytes of data. After the access head arrives at a desired track, how long on average does it take a randomly selected sector to rotate to a point directly beneath the access head? Express your answer in micro-seconds (not seconds or milli-seconds).