Andrew S. Tanenbaum (OS) Edition 4 Exercise 6 Question 26 (Page No. 467)

Question

A system has four processes and five allocatable resources. The current allocation and maximum needs are as follows:

What is the smallest value of x for which this is a safe state?

Answer 1

Start with x = 0  and make Need table

it will not satisfy any process in first step

then set x=1

it will satisfy process D need but in second step it will not able satisfy any process need

set x=2

This value will satisfy need with sequence  of Process D, C, B, A

Answer should be x=2

Answer 2

	NEED
A	0 1 0 0 2
B	0 2 1 0 0
C	1 0 3 0 0
D	0 0 1 1 0

X =2 will Satisfied all process

0 0 2 1 1