Method and apparatus for transferring speculative data in lieu of
requested data in a data transfer operation. First data are transferred
in response to an execution of a first pending command. Speculative data
are transferred instead of second data associated with a second pending
command during a next available latency period for the second data,
preferably when the speculative data are adjudged as having a utility
greater than a utility of the second data. The first and second commands
are preferably received in a queue and a command execution algorithm
identifies the second command as a next best command to be executed after
execution of the first command. The above steps are preferably carried
out by a controller of a data storage device.