Hitachi IC25N040ATCS04-0 Specifications - Page 168

13.25 Security Unlock (F2h) Command Block Output Registers Register 7 6 5 4 3 2 1 0 Data Feature Sector Count Sector Number Cylinder Low Cylinder High Device/Head 1 - 1 D - - - - Command 1 1 1 1 0 0 1 0 Command Block Input Registers Register 7 6 5 4 3 2 1 0 Data Error see below Sector Count Sector Number Cylinder Low Cylinder High Device/Head Status see below Error Register 76543210 CRC UNC 0 IDN 0 ABT T0N AMN 0V000V00 Status Register 7 6 5 4 3 2 10 BSY RDY DF DSC DRQ COR IDX ERR 0 V 0 - - 0 -V Figure 113. Security Unlock command (F2h) This command unlocks the password and causes the device to enter device unlock mode. If a 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 Figure 114 on page 156. If the Identifier bit is set to master and the drive is in high security mode then the password supplied will be compared with the stored master password. If the drive is in maximum security mode then the security unlock will be rejected. If the Identifier bit is set to user, then the drive 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 this counter reaches zero, all password protected commands are rejected until there is a hard reset or a power off. Hitachi Travelstar 60GH & 40GN hard disk drive specifications 155