IBM IC25N020ATDA04 - Travelstar 20 GB Hard Drive Specifications page 187

13.33.1.11 S.M.A.R.T. Enable/Disable Automatic Off-Line (subcommand DBh)
This subcommand enables and disables the optional feature that cause the device to perform the set of
off-line data collection activities that automatically collect attribute data in an off-line mode and then save
this data to the device's nonvolatile memory. This subcommand may either cause the device to automa-
tically initiate or resume performance of its off-line data collection activities or cause the automatic off-line
data collection feature to be disabled. This subcommand also enables and disables the off-line read
scanning feature that cause the device to perform the entire read scanning with defect reallocation as the
part of the off-line data collection activities.
The Sector Count register shall be set to specify the feature to be enabled or disabled.
Sector Count Feature description
00h Disable Automatic Off-line
01h Disable Off-line Read Scanning
F8h Enable Automatic Off-line
F9h Enable Off-line Read Scanning
A value of zero — written by the host into the device's Sector Count register before issuing this
subcommand — shall cause the automatic off-line data collection feature to be disabled. Disabling this
feature does not preclude the device from saving attribute values to nonvolatile memory during some
other normal operation — such as during a power-on, during a power-off sequence, or during an error
recovery sequence.
A value of one written by the host into the device's Sector Count register before issuing this subcommand
shall cause the off-line read scanning feature to be disabled. The Device does not perform the off-line
read scanning at the off-line data collection activities which is initiated by the S.M.A.R.T. Execute Off-line
Immediate(Subcommand D4h) or automatically if the off-line read scanning feature is disabled.
A value of F8h — written by the host into the device's Sector Count register before issuing this
subcommand — shall cause the automatic Off-line data collection feature to be enabled.
A value of F9 written by the host into the device's Sector Count register before issuing this subcommand
shall cause the off-line read scanning feature to be enabled. The Device perform the off-line read
scanning at the off-line data collection activities which is initiated by the S.M.A.R.T. Execute Off-line
Immediate (Subcommand D4h) even if the automatic off-line feature is disabled.
Any other non-zero value — written by the host into this register before issuing this subcommand — is
vender specific and will not change the current Automatic Off-Line Data Collection and Off-line Read
Scanning status. However, the device may respond with the S.M.A.R.T. error code specified in
Figure 128 on page 185.
Travelstar 48GH, 30GN & 15GN hard disk drive specifications
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