Hitachi HDS723020BLA642 Specifications page 257

Sector Number (HOB=1)
Cylinder Low (HOB=0)
Cylinder Low (HOB=1)
Cylinder High (HOB=0)
Cylinder High (HOB=1)
CCTO (Error, bit 0)
LBA (31:24) of the address of the first unrecoverable error.
LBA (15:8) of the address of the first unrecoverable error.
LBA (39:32) of the address of the first unrecoverable error.
LBA (23:16) of the address of the first unrecoverable error.
LBA (47:40) of the address of the first unrecoverable error.
CCTO bit shall be set to one if a Command Completion Time Limit Out error has
occurred.
Hitachi hard disk drive specifications
257