Virtual Memory

• A computer can use part of the hard disk drive as virtual memory. This means that the hard drive memory can act like RAM (random access memory). This allows the processor to continue running applications even when running out of space.
  
  

Paging

• When the system's RAM is too busy, the computer's processor moves the processes that are idle to space on the hard drive. This is known as paging, and the files that are created in the virtual memory space are called page files.
  
  

Address Mapping

• As the computer's RAM become free, the processor moves the page files out of the virtual memory space into RAM. The memory management unit (MMU) is responsible for keeping track of where these files are relocated. This connecting of virtual addresses to physical address is called address mapping. Part of the MMU's memory contains a table for mapping addresses. This table is known as the translation look-aside buffer (TLB). This helps the processor keep track of page files as they are swapped to the physical memory.