Volume II: Troubleshooting - Disk

Media Defect Management

Embedded SCSI Disk Drives

The FORMAT UNIT command formats the media so that all data blocks can be accessed. The following lists are used during the defect management process.

Primary, or Manufacturer's, Defect List (P list)

The P list supplied by the manufacturer is resident on the disk drive. The initiator can reference this list with the READ DEFECT DATA command. The initiator cannot change or erase the Primary list.

Certification Defect List (C list)

The C list is the position information of defective data blocks detected during data block verification after initialization when the FORMAT UNIT command is issued. These defects are added to the Grown list.

Data Defect List (D list)

The D list is the defect position information transferred from the initiator upon execution of the FORMAT UNIT command. These defects are added to the Grown list.

Grown Defect List (G list)

The G list includes defects identified to, or by, the drive. It does not include the P list. These defects are classified as flaws appearing after the media is formatted. The initiator may request that the current G list be used during formatting, or that the current G list be erased and a new list begun. Entries to the G list include:

1. Defects provided to the drive in D lists during previous FORMAT UNIT commands.
2. Drive C list defects detected during previous FORMAT UNIT commands.
3. Defects appended by successful completion of the REASSIGN BLOCKS command.