How does virtual memory differ from main memory and secondary memory?
As a computer design feature, virtual memory gives the illusion that a computer has more memory than it actually has. It is a way for software to use more and more memory than the computer physically has. According to Microsoft, virtual memory is defined as a temporary storage device used by a computer to run programs that require more memory than it has.
As an example, a program can access as much as 4 GB of virtual memory. For example, if a computer has 128 MB of RAM, it can access 192 MB of virtual memory. This means it can access 1.5 times more virtual memory based on the amount of RAM it has.In other words, the computer appears to have more primary storage space than it actually has by using secondary storage (hard disks) as primary storage (RAM).
There are several ways in which virtual memory differs from main memory and secondary memory:
1) A program can generate or create virtual memory when it needs it, but main memory, such as RAM, is a loading memory that loads a program into the computer, while ROM, a startup memory that boots the computer, and secondary memory, such as hard disks, magnetic tapes, and optical disks, is used to store data permanently on a computer.
2) The virtual memory does not have a physical appearance, but the main memory and secondary memory do.
3) In virtual memory, secondary memory is used to act as primary memory so that computers appear to have more primary memory for better performance, although main memory and secondary memory are both critical components for computer operation.