Multi threading operating system

Multi threading

operating system

· Multi threading is a technique in which a process, executing an application is divided into threads that can run concurrently

· A thread is a dispatch able unit of work. It includes a processor context and its own data area for sack .

· A thread execute sequentially and is interruptible so that the processor can turn to another thread.

· Thus, a thread represents a light weight process and is the smallest unit of CPU utilization it is like a mini process.

· A process, on other hand is a collection of one or more threads and associated system resources

· A thread is not a process by itself. Cannot run on its own. It always run within a process.

· Thus, a multithreaded process may have multiple execution flows, different once belonging to difficult threads.

Multi Threading Operating

System

A thread is not a process by itself .it cannot run on its own. It always run within a process

The various States exhibited by windows thread are:

1. Ready. A ready thread may be scheduling for execution. The kernel dispatcher keeps track of all ready threads and schedules them in priority order.

2. Standby. A thread that has been selected to run next on a particular processor is said to be in standby state. The thread waits in this state until the processor is made available.

3. Running the thread that is currently CPU is in running state.it keeps the processor until it is preempted by a higher priority thread or it gets blocked or its time slice expires.

4. Waiting. A thread enters waiting state when:

(a) It is blocked on event .

(b) It voluntarily waits for synchronization purpose.

When waiting condition is satisfied, the thread moves back to ready state if all the resource are available.

5. Transition. A thread enters this state after waiting if it is ready to run but resources are not available.

6. Terminated. A thread can be terminated by itself, by another thread or when its parent process terminates.

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