why is the below state although being unsafe not leading to deadlock ?

Question

I got the state to be unsafe since Available is (1,1) which can't satisfy the need of any process so why is not deadlock ?

Answer 1

Unsafe states are necessary condition for deadlock.

Like in this case if we run T1, T2 serially then no deadlock. But interleaved execution of T1, T2T2  may create deadlock condition. U can't say always deadlock, so better to say Unsafe

Comments

here i think any execution cannot satisfy the needs of process . and no safe sequence is possible .

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Type  1 followed by Type  2 ???

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So in general if the available is not able to meet the requirement of any process so should I simply declare it to be unsafe state ?

Answer 2

it will be a deadlock as the execution of any process cannot complete in any possible way of execution. unsafe state means the system may go to deadlock if not executed in a determined manner.

Answer 3

Being in a deadlock or being into unsafe state are two different things . Unsafe state is a state which MAY lead to deadlock but it has not happened yet , sometimes this may also happen if some process does not require max resources and it will terminate leaving resources for other processes , hence deadlock can be avoided in this way from unsafe state . For more info this can be referred https://cs.stackexchange.com/questions/45145/why-unsafe-state-not-always-cause-deadlock