HYBRID DRIVE BALANCING EXECUTION TIMES FOR NON-VOLATILE SEMICONDUCTOR MEMORY AND DISK

A hybrid drive is disclosed comprising a head actuated over a disk, and a non-volatile semiconductor memory (NVSM). A first execution time needed to execute commands in a NVSM command queue is estimated, and a second execution time needed to execute commands in a disk command queue is estimated. An access command is inserted into a selected one of the NVSM command queue and the disk command queue in response to the first and second execution times, and one of the first and second execution times is updated in response to an estimated execution time of the access command.