Operating System - Virtualization in Operating Systems

Virtualization is a technology that allows a single physical computer system to run multiple operating systems at the same time. Instead of installing one operating system directly on hardware, virtualization creates virtual versions of computers called virtual machines. Each virtual machine behaves like an independent computer with its own operating system, applications, memory, and storage.

Basic Idea of Virtualization

Normally, one computer runs one operating system that directly controls hardware resources such as CPU, memory, storage, and network devices. In virtualization, a special software layer called a hypervisor is placed between the hardware and operating systems. The hypervisor divides physical resources and allocates them to multiple virtual machines.

Each virtual machine believes it is running on its own dedicated hardware even though all machines share the same physical system.

Components of Virtualization

Physical Machine
The real computer hardware including processor, RAM, storage, and network devices.

Hypervisor
Software responsible for creating and managing virtual machines. It controls how hardware resources are shared.

Virtual Machine (VM)
A software-based computer system that runs its own operating system and applications independently.

Guest Operating System
The operating system installed inside a virtual machine.

Host Operating System
The main operating system installed on the physical computer when using hosted virtualization.

Types of Virtualization

Full Virtualization
The guest operating system runs without modification. The hypervisor completely simulates hardware.

Para-Virtualization
The guest operating system is modified to communicate efficiently with the hypervisor for better performance.

OS-Level Virtualization
Multiple isolated environments share the same operating system kernel. Containers are an example of this method.

Types of Hypervisors

Type 1 Hypervisor
Runs directly on hardware without a host operating system. It provides high performance and is commonly used in data centers.

Type 2 Hypervisor
Runs as an application on an existing operating system. It is mainly used for learning, testing, and development purposes.

Advantages of Virtualization

Efficient use of hardware resources by running multiple systems on one machine.
Reduced hardware cost and power consumption.
Easy backup and recovery using VM snapshots.
Safe testing environment for new software or operating systems.
Improved system isolation and security.

Disadvantages of Virtualization

Performance may be slightly lower compared to running directly on hardware.
Requires sufficient RAM and CPU resources.
Configuration and management may become complex in large environments.

Applications of Virtualization

Cloud computing platforms use virtualization to provide virtual servers.
Software developers test applications on multiple operating systems.
Organizations run legacy applications on modern hardware.
Educational institutions use virtual labs for students.

Conclusion

Virtualization is a fundamental technology in modern computing. It improves resource utilization, flexibility, and system management. Many technologies such as cloud computing, server consolidation, and modern application deployment depend heavily on virtualization concepts.