Virtual Memory

A method to manage system memory.

Feature

Allow process to be execute without put all its code into memory.

Allow user to use more memory than the real memory of a computer.

Pro

Enable to run a large program

Architecture

There are logical memory, page table and physical memory.

For an application,

1. it will execute the continuous logical memory
2. Logical memory: Point to a page table
3. Page table: Check if data is valid in the physical memory
   1. valid: read the data
   2. invalid: load data from disk to physical memory