Fault Prevention deals with preventing faults being incorporated into a system. This can be accomplished by use of development methodologies and good implementation techniques. Dependability means are intended to reduce the number of failures presented to the user of a system. Failures are traditionally recorded over time and it is useful to understand how their frequency is measured so that the effectiveness of means can be assessed.11  
Fault Prevention deals with preventing faults being introduced into a system. This can be accomplished by use of development methodologies and good implementation techniques. Dependability means are intended to reduce the number of failures made visible to the end users of a system. Persistence Based on how faults appear or persist, they are classified as: Transient: They appear without apparent cause and disappear again without apparent cause Intermittent: They appear multiple times, possibly without a discernible pattern, and disappear on their own Permanent: Once they appear, they do not get resolved on their own
R
incorporated
introduced
R
presented to the user
made visible to the end users
R
Failures are traditionally recorded over time and it is useful to understand how their frequency is measured so that the effectiveness of means can be assessed.11
Persistence
A
Based on how faults appear or persist, they are classified as:
A
Transient: They appear without apparent cause and disappear again without apparent cause Intermittent: They appear multiple times, possibly without a discernible pattern, and disappear on their own Permanent: Once they appear, they do not get resolved on their own