$(1)$ xv$6$ is an interrupt driven operating system.

a$)$ Give an interrupt that will cause a process to change from Running to

Blocked.

b$)$ Give an interrupt that will cause a process to change from Blocked to Ready.

Process blocks for input

Scheduler picks another process

Scheduler picks this process

Input becomes available

$(2)$ Why does a programmer have to write a system call anyway? Give two reasons.

$($Hint: "The professor made us do it$."$ will not count.$)$

$(3)$ The address space of a process contains a stack segment, a heap segment, a $.$bss

segment, a $.$data segment and a $.$txt segment. Where are the following stored?

a$)$ Dynamic data allocated by malloc$()$

b$)$ An initialized local static variable $.$

c$)$ A method