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.
Deadlock occurs when a group of processes are all blocked, each waiting for a resource held by another process in the group. This mutual waiting prevents any process from proceeding, resulting in a standstill. This is also referred to as circular wait.

Step 2: Evaluate the options based on the definition. 
(A) Accurately describes a deadlock scenario, specifically the circular wait, where Process 1 needs a resource from Process 2, and Process 2 needs a resource from Process 1. 

(B) A process exceeding its time slice is managed by the scheduler through preemption, a scheduling concern, not a deadlock situation. 

(C) Insufficient memory is a memory management issue leading to process failure or system slowdown (thrashing), but it does not constitute a deadlock.

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

Conclusion: Deadlock is characterized by a group of blocked processes, each holding a resource while waiting for a resource held by another process within the group.