Virtual Memory in Operating System
Virtual Memory
Virtual Memory is a technique that if the logical address is greater than the physical address and even also load into the main memory and executes the job.
Example: Demand paging
Demand Paging
Demand paging is the application of virtual memory, it is the combination of paging and swapping. A page is not loaded into the main memory until it is needed. This scheme is called Demand paging.

Thrashing
If the number of processes submitted to the CPU for execution is increased, then the CPU utilization will also be increased. But increasing the process continues at a certain time, then the CPU utilization falls sharply and sometimes it reaches zero. This situation is said to Thrashing.