Seagate ST800FM0012 Pulsar.2 SAS Product Manual - Page 53

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10.0 Defect and error management Seagate continues to use innovative technologies to manage defects and errors. These technologies are designed to increase data integrity, perform drive self-maintenance, and validate proper drive operation. SCSI defect and error management involves drive internal defect/error management and SAS system error considerations (errors in communications between the initiator and the drive). In addition, Seagate provides the following technologies used to increase data integrity and drive reliability: • Background Media Scan (see Section 10.4) • Auto-Reallocation (see Section 10.5) The read error rates and specified storage capacities are not dependent on host (initiator) defect management routines. 10.1 Drive internal defects/errors During the initial drive manufacturing test operation at the factory, media defects are identified, tagged as being unusable, and their locations recorded on the drive primary defects list (referred to as the "P' list). At factory format time, these known defects are also deallocated, that is, marked as retired and the location listed in the defects reallocation table. The "P" list is not altered after factory formatting. Locations of defects found and reallocated during error recovery procedures after drive shipment are listed in the "G" list (defects growth list). The "P" and "G" lists may be referenced by the initiator using the READ DEFECT DATA command. Details of the SCSI commands supported by the drive are described in the SAS Interface Manual. Also, more information on the drive Error Recovery philosophy is presented in the SAS Interface Manual. The drive uses a vendor unique format to report defects via the READ DEFECT DATA command pending T10 standardization of a format for Solid State Devices. This format defect type is defined as 110b in the SCSI FORMAT UNIT command. The definition of the 110b format is defined in the following table. Table 13: Bit Byte 0 1 2 3 4 5 6 7 SSD Physical format address descriptor 7 (MSB) 6 5 4 3 2 1 0 MEDIA ID (LSB) CHANNEL DIE BLOCK (LSB) RESERVED VENDOR UNIQUE (MSB) The MEDIA ID field contains an identifier for the flash controller for devices that utilize more than one flash controller. The CHANNEL field contains the channel number within the corresponding Flash Controller. Pulsar.2 SAS Product Manual, Rev. B 45

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Pulsar.2 SAS Product Manual, Rev. B
45
10.0
Defect and error management
Seagate continues to use innovative technologies to manage defects and errors. These technologies are
designed to increase data integrity, perform drive self-maintenance, and validate proper drive operation.
SCSI defect and error management involves drive internal defect/error management and SAS system error
considerations (errors in communications between the initiator and the drive). In addition, Seagate provides
the following technologies used to increase data integrity and drive reliability:
•
Background Media Scan (see Section 10.4)
•
Auto-Reallocation (see Section 10.5)
The read error rates and specified storage capacities are not dependent on host (initiator) defect management
routines.
10.1
Drive internal defects/errors
During the initial drive manufacturing test operation at the factory, media defects are identified, tagged as being
unusable, and their locations recorded on the drive primary defects list (referred to as the “P’ list). At factory
format time, these known defects are also deallocated, that is, marked as retired and the location listed in the
defects reallocation table. The “P” list is not altered after factory formatting. Locations of defects found and
reallocated during error recovery procedures after drive shipment are listed in the “G” list (defects growth list).
The “P” and “G” lists may be referenced by the initiator using the READ DEFECT DATA command.
Details of the SCSI commands supported by the drive are described in the
SAS Interface Manual
. Also, more
information on the drive Error Recovery philosophy is presented in the
SAS Interface Manual
.
The
drive uses a vendor unique format to report defects via the READ DEFECT DATA command pending T10
standardization of a format for Solid State Devices. This format defect type is defined as 110b in the SCSI
FORMAT UNIT command. The definition of the 110b format is defined in the following table.
Table 13:
SSD Physical format address descriptor
Bit
Byte
7
6
5
4
3
2
1
0
0
(MSB)
MEDIA ID
1
(LSB)
2
CHANNEL
3
DIE
4
(MSB)
BLOCK
5
(LSB)
6
RESERVED
7
VENDOR UNIQUE
The MEDIA ID field contains an identifier for the flash controller for devices that utilize more than one flash
controller.
The CHANNEL field contains the channel number within the corresponding Flash Controller.