What is hypervisor? Types of hypervisor.

A hypervisor, also known as a virtual machine monitor (VMM), is a software or firmware that enables multiple operating systems (OS) to run concurrently on a single physical host machine. It abstracts the underlying hardware resources and creates virtual environments, called virtual machines (VMs), allowing them to share the physical resources efficiently.

Hypervisors are commonly used in server virtualization, where they play a crucial role in consolidating multiple servers onto a single physical machine, thus optimizing resource utilization, reducing costs, and simplifying management. They are also utilized in desktop virtualization and cloud computing environments.

There are two primary types of hypervisors:

Type 1 Hypervisor (Bare Metal Hypervisor):

Type 1 hypervisors run directly on the physical hardware of the host system without any underlying operating system.
They provide a layer of abstraction between the physical hardware and the virtual machines.
Since they operate at a lower level, they often offer better performance and efficiency compared to Type 2 hypervisors.
Examples of Type 1 hypervisors include VMware vSphere/ESXi, Microsoft Hyper-V (when installed on the bare metal), Xen, and KVM (Kernel-based Virtual Machine).
Type 2 Hypervisor (Hosted Hypervisor):

Type 2 hypervisors run on top of a conventional operating system, which is installed on the physical hardware.
They leverage the host operating system's device drivers and resource management capabilities.
While they are easier to install and configure, they may introduce additional overhead and slightly reduced performance compared to Type 1 hypervisors.
Type 2 hypervisors are often used for development, testing, and desktop virtualization scenarios.
Examples of Type 2 hypervisors include VMware Workstation, Oracle VirtualBox, and Microsoft Virtual PC.
Additionally, hypervisors can further be classified based on their architecture and deployment models: