Multiprogramming

In last blogs, we have discuss Process Management and Mechanism used in Early System. In this blog, we will discuss Multi-programming, but before this we will briefly discuss Uni-programming.

Uni-Programming:

Uni-programming

              In uni-programming system, only one job is processed at a time and all system resources are available exclusively for the job until its completion.

Multi-Programming:

Multi-programming

            In multi-programming system, interleaved execution of two or more different and independent programs by a computer.

            There are two types of Multi programming:

• With Fixed Tasks (MFT): Fixed number of jobs can be processed concurrently.
• With Variable Tasks (MVF): Number of jobs vary.

          Are occupied by each job residing simultaneously in the Main memory is known as a Memory Partition.

Process States in Multiprogramming:

States of processing

        In Multi-programming system, there are three states of process which are:

1. Ready: In this state process is occupied in Random Accessing Memory (RAM) and wait for execution.
2. Running: In this state process allocated the CPU and execution is start on the process.
3. Blocked: In Running state if process need any I/O operation, it goes to Blocked state and when I/O operation is completed it goes to Ready state.

Requirements of Multi programming:

• Large Memory
• Memory Protection
• Job Status Preservation
• Proper Job Mix
• CPU Scheduling

What is Multitasking?