K6602743
Rev.2
02.12.’02
- 87 -
6.3.2.11 Device Configuration Overlay Feature
The Device Configuration Overlay feature set allows a utility program to modify some of the commands,
modes, and features sets that a device reports as supported in the IDENTIFY DEVICE command response
as well as the capacity reported. Commands unique to the Device Configuration Overlay feature set use a
single command code and are differentiated from one another by the value placed in the Features register.
These commands are:
−
DEVICE CONFIGURATION FREEZE LOCK
−
DEVICE CONFIGURATION IDENTIFY
−
DEVICE CONFIGURATION RESTORE
−
DEVICE CONFIGURATION SET
The Device Configuration Overlay feature set affects the IDENTIFY DEVICE command responses. Certain
bits in these words that indicate that a command, mode, capacity, or feature set is supported and enabled
can be cleared by a DEVICE CONFIGURATION SET command. Since a host protected area may be lost if
the capacity of the device is reduced, an attempt to modify the maximum capacity when a host protected
area is set will cause the DEVICE CONFIGURATION SET command to return command aborted. If a
DEVICE CONFIGURATION FREEZE LOCK command has been issued since the device powered-up, the
DEVICE CONFIGURATION RESTORE SET command returns command aborted. The settings made by a
DEVICE CONFIGURATION SET command are maintained over power-down and power-up.
A DEVICE CONFIGURATION IDENTIFY command indicates the selectable commands, modes, capacity,
and feature sets that the device is capable of supporting. After the execution of DEVICE CONFIGURATION
SET command this information is no longer available from an IDENTIFY DEVICE command.
A DEVICE CONFIGURATION RESTORE command disables an overlay that has been set by a DEVICE
CONFIGURATION SET command and returns the IDENTIFY DEVICE command response to that indicated
by the DEVICE CONFIGURATION IDENTIFY command. Since a host protected area may be lost if the
capacity of the device is reduced, an attempt to modify the maximum capacity when a host protected area is
set will cause the DEVICE CONFIGURATION RESTORE command to return command aborted. If a
DEVICE CONFIGURATION FREEZE LOCK command has been issued since the device powered-up, the
DEVICE CONFIGURATION RESTORE command returns command aborted.
A DEVICE CONFIGURATION FREEZE LOCK command prevents accidental modification of the state of the
Device Configuration Overlay feature set. A device always powers-up with configuration freeze lock not set.
After a successful DEVICE CONFIGURATION FREEZE LOCK command is executed, all DEVICE
CONFIGURATION SET, DEVICE CONFIGURATION IDENTIFY, and DEVICE CONFIGURATION
RESTORE commands are aborted by the device until the device is powered-down and powered-up again.
The freeze locked state is not affected by hardware or software reset.
