Seagate 2531 Computer Drive User Manual


 
1.7.4 Power-management modes
This drive provides programmable power management to provide
greater energy efficiency. In most systems, you can control power
management through the system setup program. This Seagate drive
features several power-management modes, which are summarized in
the following table and described in more detail below:
Mode Heads Spindle Buffer
Active Moving Rotating Enabled
Idle Move every 3 minutes Rotating Enabled
Standby Parked Stopped Enabled
Sleep Parked Stopped Disabled
Active mode.
The drive is in Active mode during the read/write and seek
operations.
Idle mode.
At power-on, the drive sets the idle timer to enter Idle mode
after 5 seconds of inactivity. You can set the idle timer delay using the
system setup utility. In Idle mode, the spindle remains up to speed. Every
3 minutes, the drive performs a random seek. The buffer remains
enabled, and the drive accepts all commands and returns to Active mode
any time disc access is necessary.
Standby mode.
The drive enters Standby mode when the host sends a
Standby Immediate command. If the host has set the standby timer, the
drive can also enter Standby mode automatically after the drive has been
inactive for a specifiable length of time. The standby timer delay is system-
dependent and is usually established using the system setup utility. In
Standby mode, the buffer remains enabled, the heads are parked and the
spindle is at rest. The drive accepts all commands and returns to Active
mode any time disc access is necessary.
Sleep mode.
The drive enters Sleep mode after receiving a Sleep
Immediate command from the host. The heads are parked and the
spindle is at rest. The drive leaves Sleep mode after it receives a Hard
Reset or Soft Reset command from the host. After receiving a soft reset,
the drive exits Sleep mode and enters Standby mode with all current
emulation and translation parameters intact.
Idle and standby timers.
The drive sets the default time delay for the idle
timer at power-on. In most systems, you can set this delay using the system
setup utility. Each time the drive performs an Active function (read, write or
seek), the idle and standby timers are reinitialized and begin counting down
from their specified delay times to zero. If the idle timer reaches zero before
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