BCS1333 OS :Chapter 7 Deadlocks

1.)    What is deadlock?
2.)    Draw four (4) symbols used in Resources-Allocation Graph as follows.

I ) Process
II) Resources Type with three instances
III) Pi requests instances of Rj
IV) Pi is holding an instances of Rj
 
3.)    Draw resources-allocation graph for the following situation.
 The sets P,R and E:
•    P = {P1,P2,P3}
•    R= {R1,R2,R3,R4}
•    E = {P1->R1, P2->R3,R1->P2, R2->P2, R2->P1, R3->P3}
Resources Instances:
•    One instance of resources type R1
•    Two instancesof resources type R2
•    One instance of resources type R3
•    Three instance of resources type R4