Fujitsu MAX3073NC - SCSI,80, Dell DC961,Hard Drive Scsi Logical Interface Specifications page 104

Command Specifications
It is possible to select the disk drive's spindle motor starting mode through the setting terminal on the
IDD. If prohibition of motor starting control is set by this command at the setting terminal, the spindle
motor starts automatically when the IDD's power is switched on. It is also possible to delay the starting
time through the specifications in the CHANGE DEFINITION command. When the setting terminal is
being set to perform motor starting control by command, the IDD's spindle motor will not start even
when the power is switched on. In this case, it is necessary for the INIT to issue a command to start the
spindle motor. See the description of the motor starting mode in Section 5.3.2 of the Product Manual
concerning the setting terminal.
Note:
The setting terminal specifies only the spindle motor starting method at power on time, and
whichever mode is set, this command is valid.
The INIT can issue this command whenever it is desired and stop or start the spindle motor
regardless of the state of the setting terminal.
Depending on the value specified in the "Immed (immediate)" bit, bit 0 of CDB byte 1, the timing of
completion (status 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 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 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.
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