Test by Bikram | Operating Systems | Test 2 | Question: 2

Question

Consider an operating system containing $n$ processes each requiring $4$ resources. The maximum number of processes that can be executed without any deadlock if there are $21$ resources is available  ______

Answer 1

The standard Rule is :

 "  A system with m resources of same type being shared by n processes.  Resources can be requested and released by processes only on at a time . 

The system is deadlock free if and only if --> The sum of all max needs is < m+n " 

Now here in this question 

1. n processes each requiring 4 resources. So  total maximum need  are 4n.

2. There are 21 resources are in total which is shared by n processes.

so applying above stated Rule 

4n < 21+n 

=> 3n< 21 

=> n < 7 hence number of process must be less than 7 , which is 6 at maximum .( asked in the question) .

Comments

is thiz standard formula ?

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 The system is deadlock free if and only if 

The sum of all max needs is < m+n 

This Rule use here.

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i know what is banker algo ....tell wht u want to say.

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yes @wanted , please see what i did here, 

The standard Rule is :

 "  A system with m resources of same type being shared by n processes.  The system is deadlock free if and only if --> The sum of all max needs is < m+n " 

Now here in this question 

1. n processes each requiring 4 resources. So  total maximum need  are 4n.

2. There are 21 resources are in total which is shared by n processes.

so applying above stated Rule 

4n < 21+n 

=> 3n< 21 

=> n < 7 hence number of process must be less than 7 , which is 6 ( as maximum no of process can be executed asked in the question ).