Assume that we are debating whether to implement operating system functionalities X$,$ Y$,$ and Z as user$-$space programs or not. Based on the following facts, provide opinions on whether implementing each of these functionalities as a user$-$level program would be a good idea $($give your opinions separately for $,$X$,$Y and Z$).$ Remember to provide the reasons as well.

X: contains interrupt handler code

Y: the code size is huge

Z: the functionality needs to be frequently invoked by programs on the system