Skip to main content

Suspend a process

 

Suspend a process


A process is an active program. It can also be said as a program that is under execution. It is more than the program code as it includes the program counter, process stack, registers, program code etc. Compared to this, the program code is only the text section.

A process passes through different states as it executes. These states may be different in different operating systems. However, the common process states are explained below with the help of a diagram −

OS States

New

This is the state when the process has just been created. It is the initial state in the process life cycle.

Ready

In the ready state, the process is waiting to be assigned the processor by the short term scheduler, so it can run. This state is immediately after the new state for the process.

Ready Suspended

The processes in ready suspended state are in secondary memory. They were initially in the ready state in main memory but lack of memory forced them to be suspended and gets placed in the secondary memory.

Running

The process is said to be in running state when the process instructions are being executed by the processor. This is done once the process is assigned to the processor using the short-term scheduler.

Blocked

The process is in blocked state if it is waiting for some event to occur. This event may be I/O as the I/O events are executed in the main memory and don't require the processor. After the event is complete, the process again goes to ready state.

Blocked Suspended

This is similar to ready suspended. The processes in blocked suspended state are in secondary memory. They were initially in the blocked state in main memory waiting for some event but lack of memory forced them to be suspended and gets placed in the secondary memory. A process may go from blocked suspended to ready suspended if its work is done.

Terminated

The process is terminated once it finishes its execution. In the terminated state, the process is removed from main memory and its process control block is also deleted.



Reasons For Process Suspension

Swapping

The OS needs to release sufficient main memory to bring in a  process that is ready to execute.

Other OS reason

The OS may suspend a backgrounds or utility process or  a process that is suspected of causing a problem

 

Interactive user request

A user may wish to suspend the execution of a program for purpose of debugging or in connection with the use of a resource.

Timing

A process may be executed periodically and may be suspended while waiting for the next time interval

Parent process request

A parent process may wish to suspend the execution of a  descendant to examine or modify the suspended process or to coordinate the activity of descendants

 

 

 

 

 

 

 

 

 

 

Resuming A Process

·         Resuming a process means restarting it from the point at which it was suspended.

·         A suspended process needs another process for its restoration as it cannot resume itself.

·         The resume service is also called wakeup in some system

·         Whenever a process resumes any suspended process the OS inserts the target process PCB in the ready list and update its state from suspended to ready .

 

 

 

Changing The Priority Of A Process

·         The priority of a process can be  changed in run time

·         The process priority may be changed so as to increase or decrease the process ability to compete for system resources

 


Comments

Post a Comment

Popular posts from this blog

Monolithic Architecture

  Monolithic Architecture Monolith means composed all in one piece. The  Monolithic  application describes a single-tiered  software  application in which different components combined into a single program from a single platform. Components can be: Authorization — responsible for authorizing a user Presentation — responsible for handling HTTP requests and responding with either HTML or JSON/XML (for web services APIs). Business logic — the application’s business logic. Database layer — data access objects responsible for accessing the database. Application integration — integration with other services (e.g. via messaging or REST API). Or integration with any other Data sources. Notification module — responsible for sending email notifications whenever needed. Example for Monolithic Approach Consider an example of Ecommerce application, that authorizes customer, takes an order, check products inventory, authorize payment and ships ordered products. This applicat...
Post a Comment
Read more

Change the priority of a process

  Change the priority of a process You can tell the computer that certain processes should have a higher priority than others, and so should be given a bigger share of the available computing time. This can make them run faster, but only in certain cases. You can also give a process a  lower  priority if you think it is taking up too much processing power. Go to the  Processes  tab and click on the process you want to have a different priority. Right-click the process, and use the  Change Priority  menu to assign the process a higher or lower priority. There is typically little need to change process priorities manually. The computer will usually do a good job of managing them itself. (The system for managing the priority of processes is called  nice .) Does higher priority make a process run faster? The computer shares its processing time between all of the running processes. This is normally shared intelligently, so programs that are doing more ...
Post a Comment
Read more

Defination of OS(operating system) and its concepts

    What do you mean by operating system?     Definition :  An operating system is a program that act as an interface between the user of a computer and the                                      Computer hardware. Operating system is a first program that gets loaded into the memory through a process called booting. Concepts of operating system : ·                       The purpose of operating system is to provide an environment in which a user can execute program in a convenient and efficient manner. ·                       Operating system is an integrated set of program that ma...
3 comments
Read more

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...
Post a Comment
Read more

Multilevel Feedback queue scheduling (MFQ)

  Multilevel Feedback queue scheduling (MFQ) ·          Multilevel feedback queue scheduling is an enhancement of multi-levelqueue scheduling. In this scheme, processes can move between the different queue ·          The various processes are separates in different queue on the basis of their CPU Burst Char characteristics ·          If a process consumes a lot of CPU time , it is placed into a lower priority queue. Thus I/O bound and interactive process are placed in the higher priority queue and CPU bound pricesses are in lower priority ·          If a processes waits too long in a lower priority queue it is moved higher priority queue. Such an aging prevents starvation. ·          The top priority queue is given smallest CPU time Quantum ·      ...
Post a Comment
Read more