User manual
Hitachi hard disk drive specifications
186
11.35 Security Unlock (F2h)
Command Block Output Registers
Command Block Input Registers
Register
7
6
5
4
3
2
1
0
Register
7
6
5
4
3
2
1
0
Data
-
-
-
-
-
-
-
-
Data
-
-
-
-
-
-
-
-
Feature
-
-
-
-
-
-
-
-
Error
…See Below…
Sector Count
-
-
-
-
-
-
-
-
Sector Count
-
-
-
-
-
-
-
-
Sector Number
-
-
-
-
-
-
-
-
Sector Number
-
-
-
-
-
-
-
-
Cylinder Low
-
-
-
-
-
-
-
-
Cylinder Low
-
-
-
-
-
-
-
-
Cylinder High
-
-
-
-
-
-
-
-
Cylinder High
-
-
-
-
-
-
-
-
Device/Head
1
-
1
D
-
-
-
-
Device/Head
-
-
-
-
-
-
-
-
Command
1
1
1
1
0
0
1
0
Status
…See Below…
Error Register
Status Register
7
6
5
4
3
2
1
0
7
6
5
4
3
2
1
0
CRC
UNC
0
IDN
0
ABT
T0N
AMN
BSY
RDY
DF
DSC
DRQ
COR
IDX
ERR
0
V
0
0
0
V
0
0
0
V
0
-
-
0
-
V
Table 135 Security Unlock Command (F2h)
This command unlocks the password and causes the device to enter device unlock mode. If power on reset or
hard reset is done without executing the Security Disable Password command after this command is completed,
the device will be in device lock mode. The password has not been changed yet.
The Security Unlock command requests to transfer a single sector of data from the host including information
specified in Table 135 on the page 186.
If the Identifier bit is set to master and the file is in high security mode then the password supplied will be
compared with the stored master password. If the file is in maximum security mode then the security unlock will
be rejected.
If the Identifier bit is set to user, then the file compares the supplied password with the stored user password.
If the password compare fails, then the device returns an abort error to the host and decrements the unlock
attempt counter. This counter is initially set to 5 and is decremented for each password mismatch.
When security is disabled and the Identifier bit is set to User, then the device shall return command aborted.