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Ultrastar 7K2
HGST Hard Disk Drive Technical Reference Manual
28
R
ELIABILITY
Reliability Considerations
The error rates stated in this specification assume the following:
Operation of the drive at the minimum or maximum base casting temperature is intended for short time
periods only.
You can enhance the reliability of the HGST hard drive by ensuring that the drive receives adequate
cooling. “Temperature Measurement” on page.17 Provides temperature measurements and other
information that may be used to enhance the service life of the drive. Recommended airflow
information is provided in “Cooling” on page.18. The drive incorporates industry standard Self-
Monitoring, Analysis and Reporting Technology (SMART).
If the system in which the drive is installed does not meet the characteristics defined in this TRM, please
use a HGST drive that matches your system's capability.
Error Rates
The error rates stated in this specification assume the following:
The drive is operated per the DC power specified.
The drive has been formatted with the FORMAT UNIT command.
Errors previously detected as caused by media defects are excluded from further error rate
computations.
Random error distribution
Error Rates
Error Rates are specified as based upon ECC On-The-Fly data correction, automatic retries being allowed,
and all drive flaws reallocated.
Recoverable Read error rate:
Less than 1 error in 10
12
bits transferred
Unrecoverable Read error rate:
Less than 1 in 10
15
bits transferred
Mis-corrected Read error rate:
Less than 1 sector in 10
21
bits transferred
Interface Error Rate:
Less than 1 error in 10
12
bits transferred
A seek error is defined as a failure to position a head over the addressed track. As stated by the seek error rate
above, if the drive detects a seek error it will automatically perform an error recovery procedure. If this error
recovery fails, this is deemed an unrecoverable seek error and the drive will report back an ‘04’h sense key;
these errors are classified as a drive failure as defined within our MTBF specification.