Virtualization, Hypervisors and its Types

In one of the previous post when we were discussing about installing Linux, I mentioned about  installing it in a Virtual Machine. Basically this is what virtualization. It is a technology to run multiple same or different operating systems on the same machine that are completely isolated from each other. This concept has gained popularity since the x86 structure has been introduced. An example of virtualization is of Virtual Memory. Through virtual memory a computer appears to have more memory than it physically possesses. Virtual memory is mainly implemented by the concept of paging.

What are Hypervisors?

It is the main key to enable virtualization. It is a software that is installed on top of the computer hardware. It creates a virtualization layer and acts as a platform to create virtual machines. Its only the hypervisor that manages the sharing of physical resources into virtual.

Types of Hypervisors

• Type 1 Hypervisor: Bare Metal

Also known as native or embedded hypervisor. It works directly on the host hardware. It is able to run above the hypervisor. The main task is sharing and managing of hardware resources between different operating systems installed on the system. Advantage is that any problem in one VM or OS does not affect the other OS running on the hypervisor. For Example-VMware ESXi Server, Microsoft Hyper-V etc. It is completely independent of the host operating system.

• Type 2 Hypervisor: Hosted

In this case we install the hypervisor on an operating system which then supports other operating systems which are above it. Hence, it depends completely on the host operating system. Disadvantage is that any problem in the base operating system affects the entire system.
I hope all of this was able to give you a brief idea about Virtualization and Hypervisors.