Hitachi travelstar hds723020bla642 用户手册
7K200 SATA OEM Specification
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the device are predicting a lower probability of a degrading or fault condition existing. Accordingly,
lower attribute values indicate that the analysis algorithms being used by the device are predicting a
higher probability of a degrading or fault condition existing. There is no implied linear reliability
relationship corresponding to the numerical relationship between different attribute values for any
relationship corresponding to the numerical relationship between different attribute values for any
particular attribute.
12.8.3
Attribute thresholds
Each attribute value has a corresponding attribute threshold limit which is used for direct
comparison to the attribute value to indicate the existence of a degrading or faulty condition. The
numerical value of the attribute thresholds are determined by the device manufacturer through
design and reliability testing and analysis. Each attribute threshold represents the lowest limit to
design and reliability testing and analysis. Each attribute threshold represents the lowest limit to
which its corresponding attribute value can be equal while still retaining a positive reliability status.
Attribute thresholds are set at the device manufacturer’s factory and cannot be changed in the field.
The valid range for attribute thresholds is from 1 through 253 decimal.
The valid range for attribute thresholds is from 1 through 253 decimal.
12.8.4
Threshold exceeded condition
If one or more attribute values are less than or equal to their corresponding attribute thresholds,
then the device reliability status is negative, indicating an impending degrading or faulty condition.
12.8.5
S.M.A.R.T. commands
The S.M.A.R.T. commands provide access to attribute values, attribute thresholds and other logging
and reporting information.
12.8.6
S.M.A.R.T operation with power management modes
The device saves attribute values automatically on every head unload timing except the emergency
unload, even if the attribute auto save feature is not enabled. The head unload is done not only by
Standby, Standby Immediate, or Sleep command, but also by the automatic power saving functions
like ABLE-3 or Standby timer. So basically it is not necessary for a host system to enable the
like ABLE-3 or Standby timer. So basically it is not necessary for a host system to enable the
attribute auto save feature, when it utilizes the power management. If the attribute auto save
feature is enabled, attribute values will be saved after 30minutes passed since the last saving,
besides above condition.
besides above condition.
12.9 Security Mode Feature Set
Security Mode Feature Set is a powerful security feature. With a device lock password, a user can
prevent unauthorized access to hard disk device even if the device is removed from the computer.
New commands are supported for this feature as below.
prevent unauthorized access to hard disk device even if the device is removed from the computer.
New commands are supported for this feature as below.
Security Set Password
(‘F1’h)
Security Unlock
(‘F2’h)
Security Erase Prepare
(‘F3’h)
Security Erase Unit
(‘F4’h)
Security Freeze Lock
(‘F5’h)
Security Disable Password
(‘F6’h)
12.9.1
Security mode
Following security modes are provided.
Device Locked mode
The device disables media access commands after power on. Media access
commands are enabled by either a security unlock command or a security
erase unit command.
commands are enabled by either a security unlock command or a security
erase unit command.
Device Unlocked mode
The device enables all commands. If a password is not set this mode is