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Bit 1 (LoEj (load/eject) of byte 4 of the CDB is the exclusive bit which controls
devices with replaceable recording media, and it has no meaning for the IDD. The
IDD disregards the value specified in this bit and controls the Power Condition in
accordance with the "Start" bit only.
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")
−
−
b.
In the case of the stop specification ("Start" bit = "0")
−
−
C141-C009
When the Immed bit is "1," the power condition state becomes
Active_Wait, the GOOD status is reported, and command execution is
completed.
When the Immed bit is "0," the power condition state becomes
Active_Wait, and the spindle motor is started after the NOTIFY
(ENABLE SPINUP) primitive has been received. Then, when the disk
drive enters the ready state, the status byte is reported and command
execution is completed. In this case, the INIT has no means of detecting
the timing when the power condition state becomes Active_Wait, and
there are no limitations on the time period in which the system waits the
NOTIFY (ENABLE SPINUP) primitive. Therefore, the INIT needs to
issue the NOTIFY (ENABLE SPINUP) primitive after this command is
issued and before the spindle motor becomes ready.
When the Immed bit is "1," after the power condition state becomes
Stopped, instructing the drive to stop the spindle motor is sufficient so
that the GOOD status is reported and command execution is completed.
When the Immed bit is "0," after the power condition state becomes
Stopped and the spindle motor enters the Stopped state, the status byte is
reported and command execution is completed.
4.1 Control/Sense Commands
4-81
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