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

Single partition allocation, Multiple-partition allocation and Fixed Equal-size partitions in operating system-computer world

  Single partition allocation, Multiple-partition allocation and Fixed Equal-size partitions in operating system Single partition allocation In this scheme operating system is residing in law memory and user process are executing in higher memory. Advantages It is simple  It is easy to understand and use Disadvantages User job is limited to the size of available memory. It leads to poor Utilization of processor and memory. Multiple-partition allocation  It is the simplest method for allocating  memory is divided memory into several fixed size partitions. Fixed Equal-size partitions It divides the main memory Into equal number of fixed sized partitions, operating system occupies some fixed portion and remaining portion of main memory is available for user processes. Advantages It supports multi programming. A process whose size is less then or equal to the partitions size can be loaded into any available partition. Disadvantages If a program is big to fit in...
Post a Comment
Read more

Difference between HTML and DHTML-computer world

     Difference between HTML and DHTML  HTML is a markup language, while DHTML is a collection of Technology.  DHTML creates dynamic web page, whereas HTML create static web page.  DHTML allow including small animations and dynamic menus in web pages but HTML is not able to do so.   HTML used events, methods, properties to insulate dynamism in HTML pages.   HTML is used to describe the web page but DHTML is a collection of JavaScript and style sheet in an HTML page. HTML sites will be show upon client side Technologies, while  DHTML site will be fast enough upon client side Technologies as most of entries are checked on browser itself and not waste time rendering to server for mistake.  HTML creates a plain web page without any style and scripts called as HTML. Whereas,  DHTML creates a page with HTML, CSS,DOM And scripts called as DHTML.  HTML cannot any server side code but XHTML may contain server side code.  ...
Post a Comment
Read more

Distributed transaction model-oocomputerworld

  Distributed transaction model Distributed transaction model:- To access the various data items in a distributed system is usually e accomplished through transaction there are two type of transaction that we need to consider The local transaction The Global transaction    The local transaction:- The local transaction are those that access and update data is only one local database.  The global transaction:- global transaction are those that access and update data in several local database in the case of global transaction the task is more complicated since several nodes may be participating in execution the failure of a communication link connecting these nodes may result in erroneous computation.  System structure :- Each node has its oven local transaction manager whose function is to ensure those transaction that execute at that site. The various transaction manager corporate to execute global transaction. To understand how such a manager can be impl...
Post a Comment
Read more