A disk drive and method are disclosed for data transfer initiated by
nonstandard disk-drive commands on a serial interface that only supports
standard disk-drive commands. In the method, a nonstandard disk-drive
command for data transfer is embedded within a first data block
accessible using a first standard disk-drive command. The first standard
disk-drive command is transmitted through the serial interface causing
the first data block to be transferred from the host computer to the disk
control system. The embedded command is extracted from the transferred
first data block and provided to the disk control system. A status
response is transmitted to the host computer based on the extracted
command. At least one additional standard disk-drive command is
transmitted through the serial interface to the disk control system for
transferring the identified data between the host computer and the disk
drive.