Skip to main content

Shortest job next scheduling in operating system-computer world

 Shortest job next scheduling 

Shortest job Next Scheduling (SJN) is also known as shortest job first(SJF). In SJF Scheduling the processes which have the smallest execution time is chosen for the next execution. When the CPU is available, it is assigned to the process that has the smallest next CPU burst. If the next CPU burst of two processes is same then FCFS Scheduling is used to break the tie. SJF Scheduling gives the minimum average waiting time fir a given set of processes. Moving a short process before a long process the waiting time of short process more then it increase the waiting time of long process so the average waiting time decrease. 

Process.                                  Burst time

A1                                                 6

A2                                                 8

A3                                                 7

A4                                                 3

The waiting time for process A1 = 3 millisecond 

The waiting time for process A2 = 16 millisecond 

The waiting time for process A3= 9 millisecond 

The waiting time for process A4 = 0 millisecond 

Thus the average waiting time = (3+16+9+0)/4 =7 millisecond 


Comments

  1. Zulkarnain aliDecember 26, 2020 at 11:07 AM

    amazing bro lekin abka theme thoda kharab ha agar apko woozone theme ya koi doosra theme chahiya toh mujha batana christmas offer chal raha ha wo bhi 80 percent off ka sath sirf 299 rs ma 100% original with gsl license pora saal bhar ka sabsa bada offer
    email karo ya insta pe dm my id zulkrnain_ali_zab

    ReplyDelete

Post a Comment

Popular posts from this blog

Deadlock in operating system-computer world

  Deadlock in operating system-computer world Deadlock :  In a multi-programming environment, many process may complete for a minute number of resources. A process make a request for a resource and if the resource is not available at that time, the process enter In a waiting state. A waiting state process is never again-able to change state because the resource it has requested is held by other waiting process. This situation is called deadlock. So we can say that a process is said to be deadlock when it is waiting for an event or resources which will never occurs.   so we can say that in this situation none of the process gets executed  since the resource it needs, is held by some other process which is also waits for some other resource to be released.  Let's assume that there are three process P1, P2, p3 and three different resources R1, R2 and R3. R1 is assigned to p1, R2 is assigned to P2 and R3 is assigned to P3.   After somet...
9 comments
Read more

What is sound card, video card, TV tuner card and network adapter card-computer world

 What is sound card, video card, TV tuner card and network adapter card Sound card :  Sound card is also known as audio card, sound sound board or audio output device. Sound card is a expansion card that provide the input and output of audio signals to and from a computer under control of computer programs. It is an expansion card for producing sound on computer that can be heard by speakers and headphones.  Uses of sound card :  Sound card is used for for providing the audio component  for multimedia application such as video auditing , audio auditing .It is also used in the field of education.  Video card :  It is an expansion card that connect to a computer motherboard. Video card is also known as video adapter or video controller. It is used to create a picture on display. TV tuner card : A  TV tuner card is like a television tuner that allow single to be received by a computer. TV tuner c...
2 comments
Read more

What is computer and its characteristics-computer world

  What is computer and its characteristics  Computer  :  Computer is an electronic data processing device, which accept and store data input, process the data and generates the output in a required format. computer is made up of integrated  parts (input, control, ALU, storage and output unit) All the part work together to process data so, we can say that a computer is a programmable electronic device accept row data as input and process it with  set of instruction to produce the result as output. Meaning of computer The word "computer" comes from the word "compute" which means to "calculate". The word computer is derived from the Latin word compute which means to calculate. Characteristics of computer Automatic : It is a automatic machine work by itself without human instruction. Speed :  A computer is a very fast devices. It can perform in a few second, the amount of work that a human being can do in an entire year.  Accuracy : In addition t...
1 comment
Read more