GO Classes DPP | GATE CS | Operating System | Safe Sequence Count

Answer 1

Initially,

$Work=(1,3,2)$.

Compare each process's Need with Work:

• $P_0:(0,2,1)\leq(1,3,2)$, so $P_0$ can complete.
• $P_1:(1,2,3)\nleq(1,3,2)$ because $3>2$ for resource $C$.
• $P_2:(0,1,3)\nleq(1,3,2)$ for the same reason.

Therefore the first process is forced to be $P_0$.

After $P_0$ finishes:

$Work=(1,3,2)+(2,0,1)=(3,3,3)$.

Now both remaining processes can finish:

$P_1:(1,2,3)\leq(3,3,3)$

and

$P_2:(0,1,3)\leq(3,3,3)$.

So the two possible safe sequences are:

$P_0\rightarrow P_1\rightarrow P_2$

and

$P_0\rightarrow P_2\rightarrow P_1$.
 

So, Answer : $\boxed{2}$