Operating System - Hypervisor Architecture (Type-1 and Type-2)

A hypervisor is a special software layer that allows multiple operating systems to run on a single physical computer. It creates and manages virtual machines by dividing hardware resources such as CPU, memory, storage, and network among different operating systems.

Hypervisors are mainly classified into two types based on how they interact with computer hardware.

Type-1 Hypervisor (Bare-Metal Hypervisor)

A Type-1 hypervisor runs directly on the physical hardware without requiring a host operating system. Because it communicates directly with the hardware, it provides better performance, efficiency, and security.

In this architecture:

  • The hypervisor is installed first on the system.

  • Virtual machines are created on top of the hypervisor.

  • Each virtual machine runs its own operating system independently.

Characteristics:

  • High performance

  • Better resource management

  • Strong isolation between virtual machines

  • Commonly used in data centers and cloud computing

Examples:

  • VMware ESXi

  • Microsoft Hyper-V

  • Xen Hypervisor

Type-1 hypervisors are widely used in enterprise environments where reliability and scalability are important.

Type-2 Hypervisor (Hosted Hypervisor)

A Type-2 hypervisor runs on top of an existing operating system. It behaves like a normal application installed on the computer.

In this architecture:

  • A host operating system is installed first.

  • The hypervisor runs as software inside the host OS.

  • Virtual machines operate as applications managed by the host OS.

Characteristics:

  • Easy to install and use

  • Suitable for learning, testing, and development

  • Slightly lower performance because it depends on the host OS

Examples:

  • Oracle VirtualBox

  • VMware Workstation

  • Parallels Desktop

Key Differences Between Type-1 and Type-2 Hypervisors

Type-1 hypervisors interact directly with hardware, giving faster execution and higher security. Type-2 hypervisors rely on a host operating system, which makes them simpler but slightly slower.

Importance of Hypervisor Architecture

Hypervisor technology is the foundation of modern virtualization and cloud computing. It allows efficient use of hardware, supports running multiple operating systems simultaneously, improves testing environments, and enables scalable cloud services.