Memory allows the computer to open files. there are two types of memory: Physical and Virtual.
Physical memory
Memory; also known as RAM (Random access memory). Memory stores temorary files it allows to computer to access files more quickly than using the hard drive.
Virtual Memory
Virtual memory is slower than physical memory. It uses the hard drive to open files. You can get more memory using a hard drive, but it is slower than RAM and can slow down your computer.