3.1 Control/Sense Commands
Depending on the value specified in the "Immed (immediate)" bit, bit 0 of CDB byte 1, the timing of completion (status byte report) of this command differs as shown below.
a.In the case of the start specification ("Start" bit = "1")
•When the "Immed" bit is "1," simply by instructing starting of the spindle motor, a GOOD status is reported without waiting until the disk drive is in the Ready state, and command execution is completed.
•When the "Immed" bit is "0," the status byte is reported, and command execution is completed, at the point when the disk drive has entered the Ready state after the spindle motor has started.
b.In the case of the stop specification ("Start" bit = "0")
•When the "Immed" bit is "1," simply by instructing stopping of the spindle motor, the GOOD status is reported and command execution is completed.
•When the "Immed" bit is "0," the status byte is reported, and command execution is completed, after the spindle motor is in the stopped state.
Notes:
1.When this command with the Start instruction is issued with a link to another command, the specification in the "Immed" bit should be "0." If "1" is specified for the "Immed" bit, ordinarily, the disk drive is still not in the Ready state at the point when this command is completed, so a linked command cannot be executed normally
2.Even if "1" is specified in the "Immed" bit of this command, if other commands are already queued and another command exists which is already being executed, this command is placed on the queue and disconnect processing is performed. Therefore, even if "1" is specified in the "Immed" bit, the status will not necessarily be reported immediately after the COMMAND phase.
3.1.11RESERVE (16)
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