Multiprogramming Operating System

 Multi-programming:

Multi-programming means the two or more job or task at a same time in computer memory. The job is loaded into the system and processed one at time. That is, once loaded a job will remain in the main memory until its execution is completed and the next job will be loaded only after the completion of the previous job. 


 

 

 

 

 

 

 

As shown in above diagram above area of main memory occupy by operating system, and remaining area is available for user program. In the above diagram job1 is writing data to the secondary memory and on jab 2 allocated CPU time.

  Multi-programming is the name given to the interleaved execution of two or more different and independent programs by the same computer. We have been introduced to the idea of having two programs in the main memory at the same time. The operating system for overall system control and the user program for performing in the main memory and executing them concurrently. With multiple user programs simultaneously residing in the main memory, when a user program that was executing starts performing input and output operations, the CPU is allocated to another user program in the main memory that is ready to use the CPU, instead of allowing the CPU to be idle.

 


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