Seagate ST3146855LW ユーザーズマニュアル

Cheetah 15K.5 SCSI Product Manual, Rev. J

15

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 10

8

 seeks.   Unrecoverable seek errors 

(Sense Key = 04h) are classified as drive failures.

You can enhance the reliability of Cheetah 15K.5 SCSI disc drives by ensuring that the drive receives ade-
quate cooling. Section 7.0 provides temperature measurements and other information that may be used to 
enhance the service life of the drive. Section 9.3 provides recommended air-flow information.

These drives shall achieve an AFR of 0.62% (MTBF of 1,400,000 hours) when operated in an environment that 
ensures the HDA case temperatures do not exceed the values specified in Section 7.4.1. 

Operation at case temperatures outside the specifications in Section 7.4.1 may increase the AFR (decrease 
the MTBF). AFR and MTBF statistics are population statistics that are not relevant to individual units.

AFR and MTBF specifications are based on the following assumptions for Enterprise Storage System environ-
ments:

• 8,760 power-on hours per year

• 250 average on/off cycles per year

• Operating at nominal voltages

• System provides adequate cooling to ensure the case temperatures specified in Section 7.4.1 are not 

exceeded.

No routine scheduled preventive maintenance shall be required.