XL500S
ATA Command Set
2679-701211-A06
RELEASED 10/21/10 (WD CONFIDENTIAL)
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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, see the ATA-7 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
0003h
Error Recovery Control
0004h
Features Control
0005h
SCT Data Tables
0006h
Vendor specific
0007h
SCT BIST
C000h
FFFFh Vendor specific
BYTE
VALUE
DESCRIPTION
0 - 1
0001h
S.M.A.R.T. Data Structure Revision
2 -361
XX
S.M.A.R.T. Attribute Data
135 - 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
