selfdoubt os

Question

Answer 1

I am doing like this ...is it correct ???

Comments

So u r saying whatever given in question is worthless actual senerio is present in given code where mutal exclusion not satisfied? Right? ND I was not saying mutual exclusion satified for given code I am saying in a senerio I we just focus on the question word not in given code....

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yeah if the same way code would have been executed than obvio mutual exclusion would have been satisfied.

Look i am not sure it can be other way arnd too..:(

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Ya ok thanks....

Answer 2

i am not getting what you wanna say... but i will answer it.,... take n processes P1,P2,....Pn where pn is different than others

deadlock means all processes should be block, it can't be happened due to

if Pn is out side ====> it can enter at any time

if Pn is inside =====> 1) if No other process inside means Mutex =1 ===> No Problem

                                    2) if Some other processes inside, those process make Mutex=1 when they excute their exit section

 

We are using semaphores, therefore we have queue ===> No Starvation

 

Several Processes executes Critical Section at a time..

assume P1 enters ===> Mutex =0 ===> except Pn no other process can enter

Pn enters ===> Mutex = 1

P2 enters ====> Mutex =0

All these three are in Critical section at a time...

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P1 enter ,Pn enter, P2 enter , ----- P1 leave, Pn leave, ----- P1 enter, Pn enter, P3 enter repeat this process you can have many Processes in C.S.

Comments

I m saying that is there any relation or usefulness of giving explicit code in question in words and a code after question bevz both are different?? So as I interpreted is correct ???? Becz after all many process can enter into Cs at a tym

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@eyeamgj, let there are n processes

what they are saying P1,P2,P3,.....,Pn-1

wait(mutex)

CS

signal(mutex)

but for Pn only

signal(mutex)

C.S

wait(mutex)