File History and Time Machine are examples of back-up utilities offered as part of two different operating systems.
a) Explain why it is important to back up files on a computer.
b) One of the features offered by both utilities is the possibility of ‘turning back the internal computer clock’.
Explain why this is an important feature and give two occasions when a user may wish to use this feature.
c) By using diagrams and written explanation, describe how defragmentation software works.