in Operating System
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Degree of multiprogramming is controlled by Long-term scheduler?
Why?
It just moves jobs from Secondary Memory to MM?
in Operating System
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3 Answers

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Long term scheduler picks up jobs from the job queue and and creates a process. It is the job of this scheduler to decide how many processes are to be created and what are the processes that are to be created from the job queue because of the requirement that long term scheduler should create a mix of CPU bound and I/O bound processes. Hence at any point of time, long term scheduler limits the number of processes that can be there in the ready queue (i.e. in main memory) at maximum, thereby affecting the degree of multiprogramming.
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LONG TERM SCHEDULER MOVES PROGRAMS FROM SECONDARY MEMORY TO MAIN MEMORY AND THERE IT BECOMES PROCESS.

DEGREE OF MULTIPROGRAMMING IS HOW MANY  MAXIMUM PROCESS AT READY STATE .

IT IS LONG TERM BECAUSE ONCE WE DECIDE THIS MUCH PROCESS WE CANT CHANGE THAT FACT. AND WE HAVE TO STICK WITH THAT MUCH PROCESSES FOR WHOLE TIME.

4 Comments

@Shaik Masthan

DEGREE OF MULTIPROGRAMMING  IS FIXED IT IS NOT VARIABLE.

An important concept in multiprogramming is the degree of multiprogramming. The degree of multiprogramming describes the maximum number of processes that a single-processor system can accommodate efficiently. ... The primary factor is the amount of memory available to be allocated to executing processes.Nov 17, 2017

FROM WIKI

 

DEGREE OF MULTIPROGRAMMING IS ALWAYS MAX VALUE OF PROCESSES.

 

SUPPOSE WE HAVE CAPACITY OF 20 PROCESSES AND WE CAN ONLY PUT 10 PROCESSES NOW.

WE CANT SAY 10 AS DOM

WE CANT CONSIDER THIS AS DEGREE OF MULTIPROGRAMMING BECAUSE IN FUTURE ANY PROCESS CAN COME AND INCREASE SUPOSE AFTER 1 HOUR 3 MORE PROCESSES COME

DOM BECOMES 13 ACCORDING TO U

.THEN IT VIOLATE THE CONCEPT THAT IT IS MAXIMUM VALUE OF PROCESSES OUR PROCESSOR HANDELS

 

 

 

 

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if DOM is fixed, how it can be control by LTS?
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A long-term scheduler determines which programs are admitted to the system for processing. It selects processes from the queue and loads them into memory for execution. Process loads into the memory for CPU scheduling. this the work of long term scheduler.

THERE ARE SOME SYSTEM WHICH EVEN DONT NEED THIS   LTS LIKE TIME SHARING

SO BASICALLY LTS IS JUST GOING TO PUT PROCESS IN THE  MEMORY AS LONG AS MEMORY WHICH IS GIVEN TO HOLD THESE PROCESS IS NOT FULL
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 @manisha  I am agree with @somoshree

A long-term scheduler determines which programs are admitted to the system for processing. It selects processes from the queue and loads them into memory for execution. Process loads into the memory for CPU scheduling.

The primary objective of the job scheduler is to provide a balanced mix of jobs, such as I/O bound and processor bound. It also controls the degree of multiprogramming. If the degree of multiprogramming is stable, then the average rate of process creation must be equal to the average departure rate of processes leaving the system.

On some systems, the long-term scheduler may not be available or minimal. Time-sharing operating systems have no long term scheduler. When a process changes the state from new to ready, then there is use of long-term scheduler.

CPU Bound means the rate at which process progresses is limited by the speed of the CPU. A task that performs calculations on a small set of numbers, for example multiplying small matrices, is likely to be CPU bound.

I/O Bound means the rate at which a process progresses is limited by the speed of the I/O subsystem. A task that processes data from disk, for example, counting the number of lines in a file is likely to be I/O bound.

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