Command aging method for data storage devices

A method for aging queued commands in a data storage device, wherein a next command is selected from the queued commands based on a combination of an expected access time (EAT) and an incentive term. The incentive term provides for selection of older ones of the queued commands that have larger EATs, instead of younger ones of the queued commands that have smaller EATs. Preferably, the value of the incentive term begins at zero, remains at zero for some number of queue sorts (which are performed before a command is selected for execution), and then increases continuously for some number of queue sorts or indefinitely. Both the incentive term's starting value and the rate at which it increases ate user-selectable parameters, and thus can be used to control service time and throughput in the disk drive's queue.