5.0RELIABILITY SPECIFICATIONS
The following reliability specifications assume correct host and drive operational interface, including all interface timings, power supply voltages, environmental requirements and drive mounting constraints.
Seek error rate: | Less than 10 errors in 108 seeks |
Read Error Rates | Less than 10 errors in 1012 bits transferred (OEM default settings) |
Recovered Data | |
Unrecovered Data | Less than 1 sector in 1016 bits transferred |
Miscorrected Data | Less than 1 sector in 1021 bits transferred |
Interface error rate: | Less than 1 error in 1012 bits transferred |
MTBF | 1,600,000 hours |
AFR | 0.55% |
Preventive maintenance: | None required |
5.1ERROR RATES
The error rates stated in this manual assume the following:
•The drive is operated per this specification using DC power as defined in this manual (see Section 6.2).
•Errors caused by host system failures are excluded from error rate computations.
•Assume random data.
•Default OEM error recovery settings are applied. This includes AWRE, ARRE, full read retries, full write retries and full retry time.
•Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated
5.1.1Recoverable Errors
Recoverable errors are those detected and corrected by the drive, and do not require user intervention.
Recoverable Data errors use retries and correction. Application of ECC
Recovered Data error rate is determined using read bits transferred for recoverable errors occurring during a read, and using write bits transferred for recoverable errors occurring during a write.
5.1.2Unrecoverable Errors
Unrecoverable Data Errors (Sense Key = 03h) are specified at less than 1 sector in error per 1016 bits transferred. Unrecoverable Data Errors resulting from the same cause are treated as 1 error for that block.
5.1.3Seek errors
A seek error is defined as a failure of the drive to position the heads to the addressed track. After detecting an initial seek error, the drive automatically performs an error recovery process. If the error recovery process fails, a seek positioning error (Error code = 15h or 02h) will be reported with a Hardware error (04h) in the Sense Key. Recoverable seek errors are specified at Less than 10 errors in 108 seeks. Unrecoverable seek errors (Sense Key = 04h) are classified as drive failures.
5.1.4Interface errors
An interface error is defined as a failure of the receiver on a port to recover the data as transmitted by the device port connected to the receiver. The error may be detected as a running disparity error, illegal code, loss of word sync, or CRC error.
5.2RELIABILITY AND SERVICE
You can enhance the reliability of Cheetah disk drives by ensuring that the drive receives adequate cooling. Section 6.0 provides temperature measurements and other information that may be used to enhance the service life of the drive. Section 10.2 provides recommended
CHEETAH 15K.7 SAS PRODUCT MANUAL, REV. F | 12 |