Understanding Virtualization
Before Virtualization
In the early days of computing, things were quite simple — but also very expensive. Each service or application needed its own computer.
For example, if you wanted to run three different services — like a web server, a database, and an email server — you needed three separate computers.
This meant:
It was not an efficient way to use resources.
The Change: Virtualization
Then came virtualization, which changed everything!
With virtualization, one physical computer (called a host) can run multiple virtual machines (VMs). Each virtual machine acts like a separate computer, with its own operating system (guest OS) and applications.
This became possible thanks to a special kind of software called a hypervisor.
What is a Hypervisor?
A hypervisor is software that allows multiple operating systems to share a single physical machine. It divides the hardware resources (like CPU, RAM, and storage) among different virtual machines.
There are two types of hypervisors:
1. Type 1 Hypervisor (Bare-Metal Hypervisor)
Installed directly on the physical machine (no other OS underneath).
Commonly used in production environments (like data centers).
Very stable, secure, and efficient.
Example: VMware ESXi, Microsoft Hyper-V (bare metal), Xen Server.
Think of it as a dedicated system just for running virtual machines — you can’t use it for everyday tasks.
2. Type 2 Hypervisor (Hosted Hypervisor)
Installed on top of an existing operating system (like Windows or macOS).
Good for learning, testing, or development.
You can still use other applications on your computer while running virtual machines.
Example: VMware Workstation, VirtualBox.
Benefits of Virtualization
Cost Reduction: Fewer physical machines needed.
Better Resource Utilization: One server can run many services.
Easier Management: You can quickly create, copy, or delete virtual machines.
Isolation: If one VM crashes, others keep running safely.
In Short
Before virtualization → One service = One computer (expensive!) After virtualization → Many services = One computer (efficient!)
Virtualization made IT infrastructure cheaper, faster, and more flexible — and it’s now the backbone of modern cloud computing.