ATA Bus Interface and ATA Commands
Quantum Fireball Plus AS 10.2/20.5/30.0/40.0/60.0 GB AT
6-53
6.7.14.1
6.7.14.1
6.7.14.1
6.7.14.1
Power Management Commands
Power Management Commands
Power Management Commands
Power Management Commands
The Quantum Fireball Plus AS hard disk drive provides numerous power
management options. Two important options center around a count down counter
known as the automatic power down counter or APD. This counter can trigger one
of two power saving events depending on which of the two commands was most
recently issued.
•
Standby:
Once a standby command is issued, the drive enters the
standby mode. Further, each time the APD counter reaches zero in the
future, the drive enters the standby mode, the spindle and actuator
motors are off and the heads are parked in the landing zone. Receipt
of any command that requires media access causes the drive to exit the
standby command and service the host request. Each time the drive
executes the standby command, the drive will reenter the standby
mode when the APD counter reaches zero.
•
Idle:
Once an idle command is issued, each time the APD counter
reaches zero, the drive enters the standby mode. In the standby mode,
the actuator and spindle motors are off with the heads locked in the
landing area. This is the default setting.
Three commands are available which are not dependent upon the APD counter
reaching zero:
•
Sleep:
When a sleep command is received, the drive enters the sleep
mode. In the sleep mode, the spindle and actuator motors are off and
the heads are latched in the landing zone. Receipt of a reset causes the
drive to transition from the sleep to the standby mode.
•
Standby Immediate:
When a standby immediate command is received,
the drive immediately enters the standby mode.
•
Idle Immediate:
When an idle immediate command is received, after
the first decrement of the APD counter, the drive enters the idle mode.
The sleep, standby immediate, and idle immediate commands differ in a significant
way from the standby and idle commands. Specifically, sleep, standby immediate,
and idle immediate have a one-time effect and must be reissued each time their
effect is desired. In contrast, standby and idle operate in conjunction with the APD
counter and stay in effect continually, becoming non-effectual only upon issuance
of the other of these two commands. Thus, for example, once the standby command
is issued just one time, each time the APD counter reaches zero the drive will enter
the standby mode.
Note: The user has the ability to determine the value to which the
APD counter is set upon completion of any command. This
value is set by writing to the Sector Count Register a number
between 12 and 255 just prior to issuance of a standby or idle
command.
Summary of Contents for FIREBALL PLUS AS 10.2
Page 12: ...About This Manual 1 4 Quantum Fireball Plus AS 10 2 20 5 30 0 40 0 60 0 GB AT ...
Page 16: ...General Description 2 8 Quantum Fireball Plus AS 10 2 20 5 30 0 40 0 60 0 GB AT ...
Page 61: ...Basic Principles of Operation Quantum Fireball Plus AS 10 2 20 5 30 0 40 0 60 0 GB AT 5 16 ...
Page 62: ...Basic Principles of Operation 5 17 Quantum Fireball Plus AS 10 2 20 5 30 0 40 0 60 0 GB AT ...
Page 162: ...Index I 4 Quantum Fireball Plus AS 10 2 20 5 30 0 40 0 60 0 GB AT ...