Q. Differentiate between failures and faults?

Ans. Failure:-Failure is the disappearance of external results of program operation from requirements. Consequently failure is something dynamic. Failure can also be defined as deficiency in performance and attributes and excessive response time.

There are four universal ways of characterizing failure occurrence in time:-

1) Time of failure.

2) Time interval between failures.

3) Cumulative failures experienced up to a given time.

4) Failure experienced in a time interval.

Various failure classes are permanent, recoverable, transient, unrecoverable, non-corrupting and corrupting.

Fault: - fault is the imperfection in the program that when executed under particular condition causes of failure. A fault is a property of the program moderately than a property of its execution or behaviour. Different fault classes are control faults, interface faults, data faults, input/output faults, storage management faults and exception management faults.