Define and explain the concept of "multiprogramming" in the context of operating systems. How does it contribute to efficient CPU utilization?

Multiprogramming is a method used in operating systems to execute multiple programs concurrently on a single processor. It works by having the operating system keep several programs in memory at the same time. The operating system selects a job from the job pool and starts executing it. When that job needs to wait for any operation (like I/O operation), the CPU is switched to another job. So, instead of waiting for the I/O operation to complete, the CPU is used to process another job.

The main goal of multiprogramming is to keep the CPU busy as much as possible and thus, increase the system’s efficiency. When one program is waiting for I/O completion, the operating system can switch the CPU to execute another program. This way, the CPU is always executing some program and is not sitting idle, leading to efficient CPU utilization.

In summary, multiprogramming allows for multiple programs to be loaded into memory and executed concurrently, improving CPU utilization by ensuring the CPU is always busy processing tasks and not sitting idle.