Fujitsu MHW2080BS Manual Do Utilizador

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1.7  Reliability 
C141-E249 
1-11 
1.7  Reliability 
(1)  Mean time between failures (MTBF)  
Conditions of 500,000 h 
Power-on time 
24H/day or less 
 
Operating time 
50 % or less of power-on time 
 
Temperature  
5 to 45 °C (DE surface) 
 
Humidity 
8 to 90 % (ambient) 
But humidity bulb temperature 
29 °C or less 
 
Conditions of 300,000 h 
Power-on time 
24H/day or less 
 
Operating time 
50 % or less of power-on time 
 
Temperature  
5 to 60 °C (DE surface) 
 
Humidity 
8 to 90 % (ambient) 
But humidity bulb temperature 
29 °C or less 
MTBF is defined as follows: 
 
Total operation time in all fields 
MTBF= (H) 
 
number of device failure in all fields (*1) 
*1  “Disk drive defects” refers to defects that involve repair, readjustment, or 
replacement.  Disk drive defects do not include failures caused by external 
factors, such as damage caused by handling, inappropriate operating 
environments, defects in the power supply host system, or interface cable. 
(2)  Mean time to repair (MTTR)  
The mean time to repair (MTTR) is 30 minutes or less, if repaired by a specialist 
maintenance staff member. 
(3) Service life 
In situations where management and handling are correct, the disk drives requires 
no overhaul for five years or 30,000 hours of operation, whichever occurs first, 
when the DE surface temperature is less than 45
°C.  When the DE surface 
temperature exceeds 45
°C, the disk drives requires no overhaul for five years or 
20,000 hours of operation, whichever occurs first.  
Refer to item (3) in Subsection 3.2 for the measurement point of the DE surface 
temperature.  The operating conditions of Service life are based on the equal 
conditions with MTBF. 
(4)  Data assurance in the event of power failure 
Except for the data block being written to, the data on the disk media is assured in 
the event of any power supply abnormalities.  This does not include power supply 
abnormalities during disk media initialization (formatting) or processing of 
defects (alternative block assignment).