WD Green MB500M-6Gb
AT Command Set
2679-771422-A00
RELEASED 5/2/13 (WD CONFIDENTIAL)
23
4.1.4
SCT Commands
SCT commands provide capabilities not covered in ATA/ATAPI-7 for commands that do not fit the
ATA command delivery model. Some SCT commands report completion when the command begins
execution. Execution progress for these commands may be checked by requesting SCT status. For
instance, the host can track the progress of a Write Same command by issueing a status request once
per minute. See ATA8-ACS for a full description of SCT.
Table 4-4. SCT Action Codes
4.2
S.M.A.R.T. (B0h)
The S.M.A.R.T. command provides access to attribute values, S.M.A.R.T. status, and other
S.M.A.R.T. information. These commands can be used for logging and reporting purposes, and for
accommodating special user needs.
Prior to writing the S.M.A.R.T. command to the Command Register, the host must write key values
into the LBA Mid and LBA High Registers (4Fh, C2h) or the command will be aborted and an error
will be reported.
The S.M.A.R.T. command has several sub-commands that are selectable via the Features Register when
the host issues the S.M.A.R.T. command. To select a sub-command, the host must write the
appropriate sub-command code to the Features Register before issuing the S.M.A.R.T. command. The
sub-commands and their respective codes are listed below. For more detailed information on executing
S.M.A.R.T. commands, please see the ATA specification.
4.2.1
Read Attribute Values Sub-Command
This command returns a sector of data with the drive's S.M.A.R.T. data structure.
Table 4-5. Definitions for the 512 Bytes.
ACTION CODE
DESCRIPTION
0000h
RESERVED
0001h
Long Sector Access
0002h
Write Same
0004h
Features Control
0005h
SCT Data Tables
0006h
Vendor specific
0007h
BFFFh Reserved
C000h
FFFFh Vendor specific
BYTE
VALUE
DESCRIPTION
0 - 1
0010h
S.M.A.R.T. Data Structure Revision
2 - 361
XX
S.M.A.R.T. Attribute Data
362
XX
Offline data collection status
0Xh OL disabled
8Xh OL enabled
X0h scan not run
X2h scan complete
X4h scan suspended
X5h scan aborted
363
XX
Self-Test execution status byte.
00h
The previous self-test routine completed without error or no
self-test has ever been run
01h
The self-test routine was aborted by the host
02h
The self-test routine was interrupted by the host with a hard or
soft reset
