gate forum workbook

Question

Let Flag is declared Boolean Flag[2]

Process Pi                                                                     Process Pj

while(true)                                                             while(true)
{                                                                             {                                                                                               
flag[i]=true;                                                             flag[j]=true;
while(flag[j]);                                                           while(flag[i]);

<critical section>                                                   <critical section>

flag[i]=false;                                                            flag[j]=false;

<remainder section>                                              <remainder section>
}                                                                             }
 

 

The above solution satisfies:

a Mutual Exclusion only

b Mutual exclusion and bound waiting satisfy only

c Mutual exclusion, progress only

d Progress only

Comments

Initially flag [i] contain false for i = 0 and 1. in this linked question
https://gateoverflow.in/226875/critical-section

but here in question they didn't given initial value

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that is not standard question.

take every possible case

1) Flag[i] = false and Flag[j]=true

2) Flag[i] = true and Flag[j]=false

3) Flag[i] = true and Flag[j]=true

4) Flag[i] = false and Flag[j]=false

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@Shaik Masthan  how is progress possible? both can remain outside the critical section and block each other from entering. This can lead to deadlock situation.