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.

Comments

Thread

Thread What is Thread? A thread is a flow of execution through the process code, with its own program counter that keeps track of which instruction to execute next, system registers which hold its current working variables, and a stack which contains the execution history. A thread shares with its peer threads few information like code segment, data segment and open files. When one thread alters a code segment memory item, all other threads see that. A thread is also called a lightweight process . Threads provide a way to improve application performance through parallelism. Threads represent a software approach to improving performance of operating system by reducing the overhead thread is equivalent to a classical process. Each thread belongs to exactly one process and no thread can exist outside a process. Each thread represents a separate flow of control. Threads have been successfully used in implementing network servers and web server. They also provide a suitable foundation ...

Multi Level Queue Scheduling (MLQ)

Multi Level Queue Scheduling (MLQ) · Multilevel queue scheduling classifies the processes according to their types for example, a multilevel queue scheduling algorithm makes a common. · In this scheduling ready queue is divided into various queue that are called sub queues. A subqueue is a distinct operational queue · The process are permanently assigned to subqueues, generally based on some property of the process such as memory size,priority or process type · Each subqueue has its process sucheduling algorithm. For example interactive process at the foreground may use round robin scheduling while batch jobs at the background may use the FCFS method · For example, consider a system with four different queues 1. ...

Layered Operating System

Layered Operating System Layered Structure is a type of system structure in which the different services of the operating system are split into various layers, where each layer has a specific well-defined task to perform . It was created to improve the pre-existing structures like the Monolithic structure ( UNIX ) and the Simple structure ( MS-DOS ). Example – The Windows NT operating system uses this layered approach as a part of it . Design Analysis : The whole Operating System is separated into several layers ( from 0 to n ) as the diagram shows. Each of the layers must have its own specific function to perform. There are some rules in the implementation of the layers as follows. The outermost layer must be the User Interface layer. The innermost layer must be the Hardware layer. A particular layer can access all the layers present below it but it cannot access the layers present above it. That is layer n-1 can access all the layers from n-2 to 0 but it canno...

Classification of Operating System

Classification of operating systems The operating systems may be classified into different types depending upon the nature of interaction between the user and his/her program. The various types of operating system are : 1. single user operating system 2. Multi user operating system 3. Batch processing operating system 4. Multi programming operating system 5. Multi tasking operating system 6. Multiprocessing operating system 7. Time sharing operating system 8. Real time system Distributed system Multi threading operating system Single user operating system · ...

System structure operating architecture

System structure operating architecture An operating system is a construct that allows the user application programs to interact with the system hardware. Since the operating system is such a complex structure, it should be created with utmost care so it can be used and modified easily. An easy way to do this is to create the operating system in parts. Each of these parts should be well defined with clear inputs, outputs and functions. Simple Structure There are many operating systems that have a rather simple structure. These started as small systems and rapidly expanded much further than their scope. A common example of this is MS-DOS. It was designed simply for a niche amount for people. There was no indication that it would become so popular. An image to illustrate the structure of MS-DOS is as follows − It is better that operating systems have a modular structure, unlike MS-DOS. That would lead to greater control over the computer system and its various applications. T...

Easytolearn

Search This Blog