Entering FIDES Hard Disks
The following table describes the part parameters required for hard disks when a FIDES model is selected for the calculation.
Parameter
Type
Description
[Standard FIDES Parameters]
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For more information, see FIDES Standard Part Parameters.
* 
For this FIDES part, Type of Use, Protection, and Portable appear in the midst of the standard FIDES parameters when the FIDES 2009 model for parts stress or the FIDES 2004 model is selected.
Type of Use
Choice List
The way in which the device is used. Choices are:
Normal Use
Intensive Use, Ventilated
Intensive Use, Not Ventilated
Protection
Choice List
The way in which the device is protected from damage. Choices are:
Protection against shocks/vibrations
Qualification for shocks/vibrations
No special protection or qualification
Portable
Choice List
Indicates if the device is fixed or portable.
Type
Choice List [Parts Count also]
The type of device. Choices are:
EIDE Hard Disk
SCSI Hard Disk
Hard Disk Size
Real (in)
The size of the device in inches.
Avg. Access Time
Real (ms)
The average time for the device to access and return requested data in milliseconds.
Duty Cycle
Real
The percentage of time that the device is in an operational (on) state.
# of Disk Platters
Integer
The number of rapidly rotating platters with magnetic regions that store digitally encoded data.
Life Time (L10)
Real (Hours)
Required only by the FIDES 2009 model.
Expresses product life by means of the L10 parameter, which corresponds to the time at which 10% of wearout failures occur. These failures are additional to so-called random failures that are modeled using the exponential distribution with a constant failure rate.
MTTP Preventive Maintenance
Real (Hours)
Required only by the FIDES 2009 model.
The mean or average time between two periodic preventive maintenance operations. When the maintenance policy does not include any preventive maintenance, the average failure rate is calculated over the average period between two corrective maintenance operations due to wear-out failure using the parameter values provided below.
Usage Rate
Real
Required only by the FIDES 2009 model.
The usage rate during the duration of the life profile specified by Life Time (L10). This value is the sum of the operating times divided by the total duration.
Shape Factor β
Real
Required only by the FIDES 2009 model.
The shape factor for the Weibull distribution, which is used to model the wear-out type.
[Derating Parameters]
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For more information, see Derating Parameters.