Seagate U4 ST36421A - Manual (Page 38)

30 U4 Family Product Manual, Rev. D
Note. At power-on, or after a hardware or software reset, the default
values of the features are as indicated above.
3.2.4 S.M.A.R.T. commands
S.M.A.R.T. provides near-term failure prediction for disc drives. When
S.M.A.R.T. is enabled, the drive monitors predetermined drive attributes
that are susceptible to degradation over time. If self-monitoring determines
that a failure is likely, S.M.A.R.T. makes a status report available to the
host. Not all failures are predictable. S.M.A.R.T. predictability is limited to
the attributes the drive can monitor. For more information on S.M.A.R.T.
commands and implementation, see the
Draft ATA-4 Standard.
This drive is shipped with S.M.A.R.T. features disabled. You must have
a recent BIOS or software package that supports S.M.A.R.T. to enable
this feature. The table below shows the S.M.A.R.T. command codes that
the drive uses.
Note. If an appropriate code is not written to the Features Register, the
command is aborted and 0x04 (abort) is written to the Error
register.
55
H
Disable read look-ahead (read cache) feature.
82
H
Disable write cache.
AA
H
Enable read look-ahead (read cache) feature (default).
Code in Features
Register
S.M.A.R.T. Command
D0
H
S.M.A.R.T. Read Data
D1
H
Vendor-specific
D2
H
S.M.A.R.T. Enable/Disable Attribute Autosave
D3
H
S.M.A.R.T. Save Attribute Values
D4
H
S.M.A.R.T. Execute Off-line Immediate
D7
H
Vendor-specific
D8
H
S.M.A.R.T. Enable Operations
D9
H
S.M.A.R.T. Disable Operations
DA
H
S.M.A.R.T. Return Status