Seagate ST9051A, Installation Manual

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Power management mode descriptions
The ST9144 family drives feature four-phase power management
with Active, Idle, Standby and Sleep modes. Power management
is required for low-power portable systems, and is enabled
through a system-dependent set-up procedure. Consult your
system documentation for power management information.
ST9051A power management mode
descriptions
Active mode. The drive is in Active mode during the read/write
and seek operations.
Idle mode. At power-on the drive defaults to Idle mode after
5 seconds of inactivity. The spindle is up to speed. The heads are
parked and latched away from the data zones for maximum data
integrity. The drive is Ready and accepts all commands.
Standby mode. The drive enters Standby mode when a Standby
Immediate command is received from the host. The drive also
enters Standby mode after a specifiable length of time has
elapsed with the drive in Idle mode. The Standby timer is system-
dependent, and is usually established by the user with a system
utility such as Setup. In Standby mode, the SeaCache buffer
remains enabled, the heads are parked and the spindle is at rest.
The drive accepts all commands, and returns to Active mode
when disc access is necessary.
Sleep mode. The drive enters Sleep mode when a Sleep Imme-
diate command is received from the host. The heads are parked
and the spindle is at rest. The drive leaves Sleep mode when a
hard or soft reset is sent from the host. After a soft reset is
received, the drive exits Sleep mode with all current emula-
tion/translation parameters intact.
12 ST9144 Family Installation Guide, Rev. B