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

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

Shortest Job First Scheduling (SJF)

  Shortest Job First Scheduling (SJF) ·          SJF ia also known as shortest-job-next(SJN) algorithm and is faster than FCFS. ·          In SJF, the process with the least estimated execution time is selected from the ready queue for   execution. ·          For this, SJF algorithm associates with each process, the length of its next CPU burst. When the CPU is available, it is assigned to the process that has the smallest next CPU burst. ·          If tow processes have the same length of next CPU burst ,FCFS scheduling algorithm is used to break the tie. ·          SJF algorithm can be preemptive or non-preemptive.     Non-preeptive SJF ·          In non-preemptive SJF, scheduling, CPU is always assigned to the ...
Post a Comment
Read more

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

Message Delivery Protocol

  Message Delivery Protocol ·          A protocol is a set of rules and conventions shared by communicating entities . ·          Message passing can be blocking or non blocking . ·          In blocking protocol , a sender process is blocked till the message selivered to the . in this case , sender process has guarantee that the message sent by it ie delivered before it continues its execution . A blocking protocol normally includes: 1.        Blocking send : the sender process is blocked until the message is received by the receiving process or by the mailbox. 2.        Blocking receive : the receiver nlocks until a message is available thus when both sender as well as receiver is blocked ,it is known as rebdevezevous . this combination allows for tight sysnchronization between process. ·...
Post a Comment
Read more