Question

An OS contain 3 user processes each requires 2 units of resource R. The minimum number of units of R such that no dead locks will ever arise is​

Answer 1

Answer:

we have XX number of resources where XX is sum of ri−1ri−1 where riri is the resource requirement of process ii, we might have a deadlock. But if we have one more resource, then as per Pigeonhole principle, one of the process must complete and this can eventually lead to all processes completing and thus no deadlock. 

Here, n=3n=3 and ri=2ri=2 for all ii. So, in order to avoid deadlock minimum no. of resources required

=∑i=13(2−1)+1=3+1=4.=∑i=13(2−1)+1=3+1=4.

PS: Note the minimum word, any higher number will also cause no deadlock. 

Correct Answer: CC

hriday 

answered May 28, 2016edited May 22, 2019 by Naveen Kumar 3

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1 Comment

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Good

Madhab commented Dec 24, 2016