Increasing virtual memory and advantages

Virtual memory is a technique used on computers by operating systems to utilize more main memory than it is physically available. For example, a system can run 2.3 GB of process on the computer with a physical RAM of 2GB. This technique is implemented by the use of an internal hard disk. The operating system swaps out an inactive process from the RAM to the hard disk and swaps in the required process.

Users of the Windows operating system can increase or customize the size of pages that can be allocated for virtual memory on the system setting. Click on advanced system setting > performance setting > changes to customize virtual memory.

How virtual memory is implemented.

The computer’s main memory is a crucial component to achieving high system performance. It is also expensive to manufacture and hence it should be utilized to the maximum level possible. The virtual memory technique tries to utilize the available memory by utilizing storage space on the secondary storage.

The operating system splits processes to be executed into smaller parts called pages that can be allocated to the main memory. This means a single process can have more than one page. These pages may not be required for execution at the same time for a certain execution.

Now when the operating system wants to load a new page to the RAM and the space is not available it selects one of the pages that is already allocated and swaps it out to the secondary device. It then swaps in the requested page to that partition. This means the whole process is not loaded to the RAM but only pages that are being executed at that moment.

This creates an illusion of having a significant memory than it is physically available since you can load more processes even if they are partially loaded.

Advantages of using virtual memory

1. The size of the process that can be executed by the computer is not limited to the physical size of the RAM.
2. It increases the degree of multiprogramming. Since virtual memory adds extra memory it means we can execute more processes in the same system.
3. Virtual memory provides isolation by allocating each process its virtual space hence security of the process is guaranteed.  

Disadvantages of virtual memory

1. The technique requires more overhead to ensure it runs smoothly.
2. There is time wastage during the swapping of one process with another from a slower hard disk.
3. Depending on the types of page replacement policy used the system can experience a high page fault rate which can degrade system performance.

How to increase virtual memory in Windows 10

Since virtual memory uses a hard disk the user can manually set the size of the secondary storage that can be used to implement the technique. For computers using Windows 10 operating system, you can follow the following steps.

1. Open the control panel of the computer setting. 
2. Click on the system
3. Look for advanced system settings and click to open as shown below.

4. After the advanced settings > performance again click on setting > changes on virtual memory to effect the changes as shown below.

From the setting by default, the system is set to automatically manage virtual memory. However,  as a user, you can manually do the setup.

 Virtual memory vs physical memory (RAM)

Virtual Memory	Physical Memory (RAM)
Implemented using Hard disk storage.	It is purely on the Main Memory of the computer.
The user can add more memory space for the virtual memory by allocating more hard disk space.	The memory is fixed on the physical size of the RAM. To add more space unless the user buys new RAM
It is cheaper to implement virtual memory since you use a hard disk which is less costly than RAM.	Physical memory is expensive compared to virtual memory.
Execution of processes using virtual memory is slow because hard disk access is slow.	RAM memory is very fast compared to virtual memory.
Virtual memory is only implemented when the physical memory is fully utilized.	Physical memory is used throughout from the time the system boot until it is shut down.