IBM Deskstar 120 GXP, Технические характеристики

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9.7 S.M.A.R.T. function
The intent of Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T) is to protect user data and
prevent unscheduled system downtime that may be caused by predictable degradation and/or fault of the
device. By monitoring and storing critical performance and calibration parameters, S.M.A.R.T devices
employ sophisticated data analysis algorithms to predict the likelihood of near-term degradation or fault
condition. By alerting the host system of a negative reliability status condition, the host system can warn
the user of the impending risk of a data loss and advise the user of appropriate action.
9.7.1 Attributes
Attributes are the specific performance or calibration parameters that are used in analyzing the status of
the device. Attributes are selected by the device manufacturer based on the ability of that attribute to
contribute to the prediction of degrading or faulty conditions for that particular device. The specific set of
attributes being used and the identity of these attributes is vendor specific and proprietary.
9.7.2 Attribute values
Attribute values are used to represent the relative reliability of individual performance or calibration attri-
butes. The valid range of attribute values is from 1 to 253 decimal. Higher attribute values indicate that
the analysis algorithms being used by the device are predicting a lower probability of a degrading or faulty
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 faulty condition.
9.7.3 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 values 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 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 decimals.
9.7.4 Threshold Exceeded Condition
If one or more attribute values, whose Pre-failure bit of their status flag is set, are less than or equal to
their corresponding attribute thresholds, the device reliability status is negative, indicating an impending
degrading or faulty condition.
9.7.5 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.
9.7.6 Off-line read scanning
The device provides the off-line read scanning feature with reallocation. This is the extension of the off-
line data collection capability. The device performs the entire read scan with reallocation of the marginal
sectors to prevent loss of user data.
If interrupted by the host during the read scanning, the device services the host command .
9.7.7 Error log
Logging of reported errors is supported. The device provides information on the last five errors that the
device reported as described in the SMART error log sector. The device may also provide additional
Deskstar 120GXP hard disk drive specifications
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