(a) What is a Process Control Block (PCB)?

(b) Which are the main fields of a PCB?

(c) {What is the PCB used for?

(d) Who is using the PCB?

2 ) Early computer systems allowed only one process to be executed at a time. In contrast, current computer systems allow multiple programs to be loaded into memory and executed concurrently. This evolution requires the concepts of process, which is a program in execution, and process state.

(a) Draw the Seven-State Process Model, and Explain when or why a process moves from one state to an other.

Let us consider process P2 and assume that the ........................ moves it from the ...... state into the Ready state. Show the relevant parts of the Main Memory and the Process Control Block of P2 1 .

(d)Knowing that at time t:

Processes P2, P9 and P3 are in the ready state

Process P4 is running

Process P1 is waiting for the disk to complete its service Use PCB and queue structures, to draw the interesting queues of the system at time t, and at time t+1, when the request of process P1 is completed2 .