An I/O Optimizer receives an I/O request specifying a plurality of disk blocks of the disk drive for access. A plurality of I/O sub-requests is determined from the I/O request, each I/O sub-request specifying a set of one or more adjacent disk blocks of the plurality of disk blocks along the same cylinder. A plurality of execution sequences for performing the plurality of I/O sub-requests is determined. For each of the plurality of execution sequences, a total estimated execution time for performing the I/O sub-requests according to the execution sequence is calculated. One of the plurality of execution sequences for performing the I/O sub-requests is selected based, at least in part, on the total estimated execution times for the plurality of execution sequences. A disk drive controller is instructed to perform the I/O sub-requests according to the selected execution sequence.