Question

In an operating system, the "deadlock" occurs when:

• A. Two or more processes are waiting for each other to release resources
• B. A process is executed beyond its allocated time slice
• C. System runs out of physical memory
• D. When a process entered into running state

Hint:

Remember the four necessary conditions for deadlock (Coffman conditions): 

1. Mutual Exclusion: Resources cannot be shared. 

2. Hold and Wait: A process holds at least one resource and is waiting for another. 

3. No Preemption: Resources cannot be forcibly taken from a process. 4. Circular Wait: A closed chain of processes exists, such that each process holds at least one resource needed by the next process in the chain.

Answer 1

The Correct Option is A

Step 1: Define deadlock. 
A deadlock is a state in which each member of a group of processes is waiting for some other member to release a resource. Since all processes are waiting, none of them can proceed, and they are stuck in a permanent state of waiting. This situation is also known as a circular wait.

Step 2: Evaluate the options based on the definition. 
(A) This statement perfectly describes the deadlock condition, specifically the circular wait condition where Process 1 waits for a resource held by Process 2, and Process 2 waits for a resource held by Process 1. 

(B) A process exceeding its time slice is handled by the scheduler, which will preempt the process. This is related to scheduling, not deadlock. 

(C) Running out of memory is a memory management issue that can cause processes to fail or the system to slow down (thrash), but it is not a deadlock.

(D) A process entering the running state is a normal part of the process life cycle. 

Conclusion: The defining characteristic of a deadlock is a set of blocked processes each holding a resource and waiting to acquire a resource held by another process in the set.