Skip to main content

Multi Programming Operating System

 Multi programming system

·         Multi programming operating system allows multiple users to execute multiple programs using a single CPU concurrently i.e. at the same time.

·         In multiprogramming several process are kept in the main memory and CPU execute all these processes concurrently. It means, the CPU immediately switches from one process to next that are ready to get executed

·         In such an operating system when one process start process start performing the instructions from several programs at the same time.

·         Rather, it means that there are number program available to CPU and that portion of one is executed, then segment of another and so on

 

 

 


                              memory layout in multi programming system

 

 

·         In case of multiprogramming the various jobs residing in the main memory, can be in one of the following three stages

1.       Running : CPU is being used by the program

2.       Blocked : performing I/O operation

3.       Ready : waiting for CPU to be assigned to it

·         The various example of multiprogramming operation system are windows NT,OS/2, UNIX.

·         A typical scenario of jobs in multiprogramming system . at a particular instance of time , program A is not utilizing CPU as it is busy writing output data on the disk.


       single user operating system  

2.      Multi user operating system 

3.       Batch processing operating system

4.      Multi programming operating system 

5.     Multi tasking operating system 

6.       Multiprocessing operating system

7.       Time sharing operating system

8.     Real time system  

programming

The various feature required by multi programming system are:

1.        large memory

·         For a multi programming to work satisfactorily, large main memory is required to accommodate a good number of user programs along with operator system.

 

2.       Memory protection

·         Computer designed for multi programming must provide some type memory protection mechanism to prevent a programing one memory partition from changing information or instruction of a program in another memory partition.

 

3.       job status preservation

·         in multiprogramming when one running job is blocked before I/O operation ,the CPU is taken away from that job is given to some another job later on when that job has finished its I/O operation, it need to be resumed with its execution.

 

4.       Proper job mix

·         A proper mix of I/O-bound and CPU-bound processes is required so that the operation of CPU and I/O devices are balanced.

·         If all the loaded jobs need I/O At the same time  , the CPU will be adle.

                                             

                                                           jobs in multi programming system

 Advantages and disadvantages of multi programming

Advantages of multi programming:

1.       Increased throughput. Throughput increased by utilising the idle-time of CPU for running other program that are already present in the main memory.

2.       Lowered response time. Response time is lowered by recognising the priority of job as it enters the system and by processing jobs on a priority basis.

3.       Ability to assign priorities to job.  Most multi programming systems have scheme for setting  priorities for rotating programs. They specify when the CPU will rotating programs. They specify when the CPU will rotate to anther program, and which program it will rotate to.

Disadvantages of multi programming

1.       Multi programming is implemented through an operating system, which is a program that requires space in primary storage since it must be executed by the CPU. The operating system overhead os greater with multi programming that with batch processing.

2.       Jobs may have different sizes, therefore memory management is needed to accommodate them in memory .

3.       Many jobs may be ready to run on the CPU, which means that CPU scheduling is required.

 

 

One of the requirement of multi programming is the given below:

1.       CPU scheduling

·         In a multi programming system ,often  there will be situations in wich two or more jons will be in the ready state, waiting for CPU to be allocated for execution.

·         In such a case, the operating system must bdecide to which process or jobs should CPU be allocated..

·         For this a CPU scheduler select the processes and uses different CPU scheduling algorithm.

Comments

Post a Comment

Popular posts from this blog

Multi user Operating System

  Multi user operating system ·           In a multi-user operating system, multiple number of user can access different resources of a computer at a same time. ·           The access is provided using a network that consists of various personal computer attached to a mainframe computer system.                                                              diagram of multi -user operating system       ·           The various personal computer can send and receive information to mainframe computer system. ·           The example    of multi-user OS are UNIX, windows 2000,novell netware.            sing...
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

Multi processing system

  Multi processing system ·           Multi processesor system is the sytem that contain two or more processors or CPUS and has ability to simultaneously execute     several programs. Hence the name multi-processor In such a system, multiple processor share the clock, bus, memory and peripheral devices. ·           A multi processor system is also known as parallel system ·           Multi processor system are categorized into two different types:                single user operating system    2.        Multi user operating system   3.         Batch processing operating system 4.        Multi programming operating system   5.       Multi tasking operating sy...
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

Write a note on real time OS.

  Write a note on real time OS. Ans. In real time operating system , job is to be completed within the rigid time constraints otherwise job loses its meaning. A real time system functions correctly only if it return the correct result within its time constraints Thus, in a real tome system , the correctness of the computation not only depends upon the logical correctness of the but also upon the time at which the result is produced. A real time system is often used as a central device in a dedicated applications like fuel-injection system, robotics, air- traffic control, medical imaging systems, systems that control scientific  experiment, industrial control system and weapon systems .  
Post a Comment
Read more