Hitachi HDS723020BLA642 Specifications page 173

Cylinder Low (HOB=1)
Cylinder High (HOB=0)
Cylinder High (HOB=1)
CCTO (Error, bit 0)
SE (Status, bit 5)
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.
SE (Stream Error) shall be set to one if an error has occurred during the
execution of the command and the RC bit is set to one, In this case the LBA
returned in the Sector Number registers shall be the address of the first sector in
error, and the Sector Count registers shall contain the number of consecutive
sectors that may contain errors. If the RC bit is set to one when the command
is issued and ICRC, UNC, IDNF, ABRT, or CCTO error occurs, the SE bit shall
be set to one, the ERR bit shall be cleared to zero, and the bits that would
normally be set in the Error register shall be set in the error log.
Hitachi hard disk drive specifications
173