K6602743
Rev.2
02.12.’02
- 79 -
6.3.2.10 Protected Area Feature, Address Offset Feature
6.3.2.10.1 Protected Area Feature and Set Max Security Extension
A reserved area for data storage outside the normal operating system is required for several specialized
applications. Systems may wish to store configuration data or save memory to disk data in a location that
operation system can not change. Following commands are defined in this feature.
−
Read Max Address Command
−
Set Max Address Command
−
Set Max Set Password command
−
Set Max Lock command
−
Set Max Freeze Lock command
−
Set Max Unlock command
The Read Max Address Command returns the full size of disk. The Set Max Address Command sets the
maximum address for commands.
The LBA/Cylinder changed by Set Max Address command affects the Identify Device command. The
LBA/Cylinder changed by Set Max Address command affects the Identify Device command.
The Read Max Address command allows the host to determine the maximum native address space of the
device even when a protected area has been allocated.
The Set Max Address command allows the host to redefine the maximum address of the user accessible
address space. That is, when the Set Max Address command is issued with a maximum address less than
the native maximum address, the device reduces the user accessible address space to the maximum set,
providing a protected area above that maximum address. After the Set Max Address command has been
issued, the device reports only the reduced user address space in response to an Identify Device command.
A volatility bit in the Sector Count register allows the host to specify if the maximum address set is preserved
across power-on or hardware reset cycles. On power-on or hardware reset the device maximum address
returns to the last non-volatile address setting regardless of subsequent volatile Set Max Address
commands. If the Set Max Address command is issued with a value that exceeds the native maximum
address command aborted be returned.
The Set Max Set Password command allows the host to define the password to be used during the
current power-on cycle. The password does not persist over a power cycle but does persist over a hardware
or software reset. This password is not related to the password used for the Security Mode Feature set.
When the password is set the device is in the Set Max Unlocked mode.
The Set Max Lock command allows the host to disable the SET MAX commands (except Set Max
Unlock) until the next power cycle or the issuance and acceptance of the Set Max Unlock command.
When this command is accepted the device is in the Set Max Locked mode.
