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12.41 Security Erase Unit (F4h)
The Security Erase Unit command initializes all user data sectors, and then disables the device lock function.
Note that the Security Erase Unit command initializes from LBA 0 to Native MAX LBA. Host MAX LBA set by Initialize
Drive Parameter, Device Configuration Overlay, or Set MAX Address command is ignored. The protected area by Set
MAX Address command is also initialized.
This command requests to transfer a single sector data from the host including information specified in Table 196.
When security is disabled and the Identifier bit is set to User, then the device shall return command aborted.
If the password does not match, then the device rejects the command with an Aborted error.
The Security Erase Unit command erases all user data and disables the security mode feature (device lock function).
After completing this command, all user data will be initialized to zero with write operation. At this time, it is not verified
with read operation whether the sector of data is initialized correctly. Also, the defective sector information and the
reassigned sector information for the device are not updated. The security erase prepare command should be
completed immediately prior to the Security Erase Unit command. If the device receives a Security Erase Unit
command without a prior Security Erase Prepare command, the device aborts the security erase unit command.
This command disables the security mode feature (device lock function); however, the master password is still stored
internally within the device and may be re-activated later when a new user password is set. If you execute this
command on disabling the security mode feature (device lock function), the password sent by the host is NOT
compared with the password stored in the device for both the Master Password and the User Password, and then
the device only erases all user data.
The execution time of this command is set in Word 89 of Identify device information
Table 195 Security Erase Unit Command (F4h)
Command Input
Field
Description
FEATURE
N/A
COUNT
N/A
LBA
N/A
Bit Description
DEVICE
7 Obsolete
6 N/A
5 Obsolete
4 Transport Dependent
3:0 Reserved
Command
7:0 F4h
Table 196 Erase Unit Information
Word
Description
00
Control word
bits 15:3
Reserved
bit 2
Reserved
bit 1
Erase mode (1- Enhanced, 0- Normal)
bit 0
Identifier (1-Master, 0-User)
01-16
Password
(32 bytes)
17-255
Reserved
Identifier
Zero indicates that the device should check the supplied password against the user password stored
internally. One indicates that the device should check the given password against the master password
stored internally.
269
Hard Disk Drive Specification