+-=======-=======-=======-=======-=======+
| 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|-------+-------+-------+-------+-------+-------+-------+-------|
| BBK | UNC | MC | IDNF | MCR | ABRT | TK0NF | AMNF |
+======================================+

- BBK (Bad Block Detected) indicates a bad block mark was detected in the requested sector's ID field.
- UNC (Uncorrectable Data Error) indicates an uncorrectable data error has been encountered.
- MC (Media Changed) indicates that the removable media has been changed i.e., there has been a change in the ability to access the media.
- IDNF (ID Not Found) indicates the requested sector's ID field could not
be found.
- ABRT (Aborted Command) indicates the requested command has been aborted due to a drive status error (Not Ready, Write Fault, etc.) or because the command code is invalid.
- MCR (Media Change Requested) indicates that the release latch on a
removable media drive has been pressed. This means that the user wishes
to remove the media and requires an action of some kind e.g., have software issue a Media Eject or Door Unlock command.
- TK0NF (Track 0 Not Found) indicates track 0 has not been found during
a Recalibrate command.
- AMNF (Address Mark Not Found) indicates the data address mark has not
been found after finding the correct ID field.