Seagate ST9900805SS Savvio 10K.1 SAS Product Manual - Page 24

5.1.3 Seek 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. 5.1.4 Interface 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. 5.2 Reliability and service You can enhance the reliability of Savvio disc 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 8.2 provides recommended air-flow information. 5.2.1 Mean time between failure The production disc drive shall achieve an MTBF of 1,400,000 hours when operated in an environment that ensures the HDA case temperatures specified in Section 6.4 are not exceeded. Short-term excursions up to the specification limits of the operating environment will not affect MTBF performance. Continual or sustained operation at case temperatures above the values shown in Section 6.4.1 may degrade product reliability. The MTBF target is specified as device power-on hours (POH) for all drives in service per failure. Estimated power-on operating hours in the period = MTBF per measurement period Number of drive failures in the period Estimated power-on operation hours means power-up hours per disc drive times the total number of disc drives in service. Each disc drive shall have accumulated at least nine months of operation. Data shall be calculated on a rolling average base for a minimum period of six months. MTBF is based on the following assumptions: • 8,760 power-on hours per year. • 250 average on/off cycles per year. • Operations at nominal voltages. • Systems will provide adequate cooling to ensure the case temperatures specified in Section 6.4.1 are not exceeded. Drive failure means any stoppage or substandard performance caused by drive malfunction. A S.M.A.R.T. predictive failure indicates that the drive is deteriorating to an imminent failure and is considered an MTBF hit. 5.2.2 Preventive maintenance No routine scheduled preventive maintenance is required. 18 Savvio SAS Product Manual, Rev. D