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 ti me. 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. pred ictabilit y 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 disab led. 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 Regist er, the
command is aborted and 0x04 (abort) is written to the Error
register.
55HDisable read look-ahead (read cache) feature.
82HDisable write cache.
AAHEnable read look-ahead (read cache) feature

(default).

Code in Features
Register S.M.A.R.T. Command
D0HS.M.A.R.T. Read Data
D1HVendor-specific
D2HS.M.A.R.T. Enable/Disable Attribute Autosave
D3HS.M.A.R.T. Save Attribute Values
D4HS.M.A.R.T. Execute Off-line Immediate
D7HVendor-specific
D8HS.M.A.R.T. Enable Operations
D9HS.M.A.R.T. Disable Operations
DAHS.M.A.R.T. Return Status