What is deadlock in operating system with example?

By Mark Clifford, On 8th March 2021, Under Electronics and Technology
Introduction of Deadlock in Operating System. Deadlock is a situation where a set of processes are blocked because each process is holding a resource and waiting for another resource acquired by some other process.

In respect to this, how does deadlock occur in operating system?

In an operating system, a deadlock occurs when a process or thread enters a waiting state because a requested system resource is held by another waiting process, which in turn is waiting for another resource held by another waiting process.

Also Know, what are the types of deadlock?

Two types of deadlocks can be considered:
  • Resource Deadlock. Occurs when processes are trying to get exclusive access to devices, files, locks, servers, or other resources.
  • Communication Deadlock.

What causes deadlock?

In an operating system, a deadlock occurs when a process or thread enters a waiting state because a requested system resource is held by another waiting process, which in turn is waiting for another resource held by another waiting process.

How can we avoid deadlock in operating system?

7.4 Deadlock Prevention
  1. 7.4.1 Mutual Exclusion. Shared resources such as read-only files do not lead to deadlocks.
  2. 2 Hold and Wait. To prevent this condition processes must be prevented from holding one or more resources while simultaneously waiting for one or more others.
  3. 3 No Preemption.
  4. 4 Circular Wait.
An Operating system (OS) is a software which acts as an interface between the end user and computer hardware. Every computer must have at least one OS to run other programs. An application like Chrome, MS Word, Games, etc needs some environment in which it will run and perform its task. Types of Operating system.
A dead bolt, deadbolt or dead lock is a locking mechanism distinct from a spring bolt lock because a deadbolt cannot be moved to the open position except by rotating the key. A deadbolt can therefore make a door more resistant to entry without the correct key.
A deadlock is a condition where a program cannot access a resource it needs to continue. When an active application hits a deadlock, it may "hang" or become unresponsive. Resources, such as saved or cached data, may be locked when accessed by a specific process within a program.
A state is safe if the system can allocate all resources requested by all processes ( up to their stated maximums ) without entering a deadlock state. If a safe sequence does not exist, then the system is in an unsafe state, which MAY lead to deadlock.
Four Necessary and Sufficient Conditions for Deadlock
  • mutual exclusion. The resources involved must be unshareable; otherwise, the processes would not be prevented from using the resource when necessary.
  • hold and wait or partial allocation.
  • no pre-emption.
  • resource waiting or circular wait.
A SQL Server deadlock is a special concurrency problem in which two transactions block the progress of each other. The first transaction has a lock on some database object that the other transaction wants to access, and vice versa.
A deadlock happens in operating system when two or more processes need some resource to complete their execution that is held by the other process. Process 1 and process 2 are in deadlock as each of them needs the other's resource to complete their execution but neither of them is willing to relinquish their resources.
In a database, a deadlock is a situation in which two or more transactions are waiting for one another to give up locks. For example, Transaction A might hold a lock on some rows in the Accounts table and needs to update some rows in the Orders table to finish.
In computer operating systems, paging is a memory management scheme by which a computer stores and retrieves data from secondary storage for use in main memory. In this scheme, the operating system retrieves data from secondary storage in same-size blocks called pages.
Deadlock describes a situation where two or more threads are blocked forever, waiting for each other. A Java multithreaded program may suffer from the deadlock condition because the synchronized keyword causes the executing thread to block while waiting for the lock, or monitor, associated with the specified object.
The individual guidelines provide ways of identifying and eliminating the possibility that the other thread is waiting for you.
  1. AVOID NESTED LOCKS.
  2. AVOID CALLING USER-SUPPLIED CODE WHILST HOLDING A LOCK.
  3. ACQUIRE LOCKS IN A FIXED ORDER.
  4. USE A LOCK HIERARCHY.
  5. EXTENDING THESE GUIDELINES BEYOND LOCKS.
A deadlock occurs when there is a circular chain of threads or processes which each hold a locked resource and are trying to lock a resource held by the next element in the chain. For example, two threads that hold respectively lock A and lock B, and are both trying to acquire the other lock.