Hitachi HDS728080PLAT20 Specifications - Page 89

Power management features

Page 89 highlights

10.5 Power management features The power management feature set permits a host to modify the behavior in a manner which reduces the power required to operate. The power management feature set provides a set of commands and a timer that enables a device to implement low power consumption modes. HDS7280x0PLATy0 implements the following set of functions: • A Standby timer • Idle command • Idle Immediate command • Sleep command • Standby command • Standby Immediate command 10.5.1 Power mode Sleep Mode Standby Mode Idle Mode Active Mode The lowest power consumption when the device is powered on occurs in Sleep Mode. When in Sleep Mode, the device requires a reset to be activated. The device interface is capable of accepting commands, but since the media may not be immediately accessible, there is a delay while waiting for the spindle to reach operating speed. In Idle Mode the device is capable of responding immediately to media access requests. The device is executing a command or accessing the disk media with the read look-ahead function or the write cache function. 10.5.2 Power management commands Check Power Mode Idle, Idle Immediate Sleep Standby, Standby Immediate Allows a host to determine if a device is currently in, going to, or leaving standby mode. Move a device to idle mode immediately from the active or standby modes. The idle command also sets the standby timer count and starts the standby timer. Moves a device to sleep mode. The device's interface becomes inactive at the completion of the sleep command. A reset is required to move a device out of sleep mode. When a device exits sleep mode it will enter standby mode. Move a device to standby mode immediately from the active or idle modes. The standby command also sets the standby timer count. 10.5.3 Standby timer The standby timer provides a method for the device to automatically enter standby mode from either active or idle mode following a host programmed period of inactivity. If the device is in the active or idle mode, the device waits for the specified time period and, if no command is received, the device automatically enters the standby mode. If the value of the SECTOR COUNT register on Idle command or Standby command is set to 00h, the standby timer is disabled. Deskstar 7K80 Hard Disk Drive Specification 85

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Deskstar 7K80 Hard Disk Drive Specification
85
10.5
Power management features
The power management feature set permits a host to modify the behavior in a manner which reduces the power
required to operate. The power management feature set provides a set of commands and a timer that enables a device
to implement low power consumption modes.
HDS7280x0PLATy0 implements the following set of functions:
A Standby timer
Idle command
Idle Immediate command
Sleep command
Standby command
Standby Immediate command
10.5.1
Power mode
10.5.2
Power management commands
10.5.3
Standby timer
The standby timer provides a method for the device to automatically enter standby mode from either active or idle
mode following a host programmed period of inactivity. If the device is in the active or idle mode, the device waits
for the specified time period and, if no command is received, the device automatically enters the standby mode.
If the value of the SECTOR COUNT register on Idle command or Standby command is set to 00h, the standby timer
is disabled.
Sleep Mode
The lowest power consumption when the device is powered on occurs in Sleep Mode. When
in Sleep Mode, the device requires a reset to be activated.
Standby
Mode
The device interface is capable of accepting commands, but since the media may not be
immediately accessible, there is a delay while waiting for the spindle to reach operating
speed.
Idle Mode
In Idle Mode the device is capable of responding immediately to media access requests.
Active Mode
The device is executing a command or accessing the disk media with the read look-ahead
function or the write cache function.
Check Power
Mode
Allows a host to determine if a device is currently in, going to, or leaving standby mode.
Idle, Idle
Immediate
Move a device to idle mode immediately from the active or standby modes. The idle command
also sets the standby timer count and starts the standby timer.
Sleep
Moves a device to sleep mode. The device's interface becomes inactive at the completion of the
sleep command. A reset is required to move a device out of sleep mode. When a device exits
sleep mode it will enter standby mode.
Standby,
Standby
Immediate
Move a device to standby mode immediately from the active or idle modes. The standby
command also sets the standby timer count.