A method allowing a device or controller to proceSS commandS received from a device driver out of order. It requireS that the device driver attacheS a tag to each command which the controller or device can later uSe to identify the reSponSe to the command. Tagged queueing can Speed up proceSSing conSiderably if a controller ServeS deviceS of very different SpeedS, Such aS an SCSI controller Serving a mix of CD-ROMS and high-Speed diSkS. In Such caSeS if a requeSt to fetch data from the CD-ROM iSShortly followed by a requeSt to read from the diSk, the controller doeSn' t have to wait for the CD-ROM to fetch the data, it can inStead inStruct the diSk to fetch the data and return the value to the device driver, while the CD-ROM iS probably Still Seeking. (1997-07-04)
