The term “virtual” refers to something that is not physically present as independent hardware but is created and simulated using software. In computing, virtual means a logical representation of a physical resource.
👉 Virtual = “Software-made version of real hardware.”
• A physical computer → Real hardware
• A virtual machine → software-based computer.
Even though it behaves like a real machine, it does not physically exist separately.
Virtualization is a technology that abstracts physical hardware resources and creates multiple isolated virtual environments (virtual machines) on a single physical machine. It allows efficient use of hardware by sharing physical resources among multiple systems.
👉 Virtualization = Running multiple operating systems on one physical computer.
🔹 1. Abstraction
📖 Meaning: Hiding the physical hardware details from users.
👉 Users see only virtual resources, not real hardware.
Example:
📖 Physical resources are shared among multiple virtual machines.
Example:
👉 Efficient resource utilization.
📖 Each VM works independently.
If one VM crashes, others continue working.
Example:
👉 Security + Stability
Virtualization works using a software layer called a hypervisor.
Step-by-Step:
1️⃣ Physical hardware (Host machine) exists.
2️⃣ Virtualization software (hypervisor) is installed.
3️⃣ Hypervisor divides hardware resources
4️⃣ Multiple Virtual Machines (VMs) are created.
5️⃣ Each VM installs its own operating system.
Each VM:
• Has its own virtual CPU
• Has its own virtual RAM
• Has its own virtual disk
• Has its own virtual network card
Even though all share the same physical hardware.
| Term | Meaning |
|---|---|
| Hypervisor | Software that creates and manages VMs |
| Host Machine | Physical computer |
| Guest OS | OS running inside VM |
| Snapshot | Save VM state |
| vCPU | Virtual CPU |
| vRAM | Virtual RAM |
| Datastore | Virtual storage location |
Imagine a physical server:
Using virtualization, you can create:
| VM | CPU | RAM | Storage |
| VM1 | 4 cores | 16GB | 500GB |
| VM2 | 4 cores | 16GB | 500GB |
| VM3 | 4 cores | 16GB | 500GB |
| VM4 | 4 cores | 16GB | 500GB |
All run different operating systems.
Virtualization is not limited to servers. It can virtualize:
Run multiple servers on one physical machine.
Combine multiple physical disks into one virtual storage pool.
Create virtual switches, routers, VLANs.
Run desktop OS virtually (VDI).
Run apps in isolated virtual environments.
Before virtualization:
Virtualization solved these problems by increasing hardware utilization.
| Feature | Physical | Virtualized |
| Hardware Use | Low | High |
| Cost | High | Reduced |
| Deployment Time | Slow | Fast |
| Scalability | Difficult | Easy |
| Backup | Complex | Simple |
Each VM is isolated:
This makes virtualization secure and stable.
Virtualization is the foundation of cloud computing.
Cloud providers like:
Use virtualization to provide:
Without virtualization, cloud computing would not exist.
Think of a large apartment building:
Each apartment functions independently but shares same building structure.
If you are preparing for:
Understanding virtualization is mandatory.
It is used in:
Answer:
Virtual refers to something that is not physically present as independent hardware but is created and simulated using software.
In computing, it is a logical representation of physical resources, such as a virtual machine that behaves like a real computer but exists through software.
Answer:
Virtualization is a technology that abstracts physical hardware resources and creates multiple isolated virtual environments (Virtual Machines) on a single physical machine.
It allows efficient use of hardware by sharing resources like CPU, RAM, and storage among multiple systems.
Answer:
The core concepts of virtualization are:
Abstraction – Separating hardware from the operating system.
Resource Sharing – One physical machine shares CPU, RAM, and storage with multiple virtual machines.
Isolation – Each virtual machine works independently.
Answer:
A Hypervisor is virtualization software that manages and controls virtual machines.
It divides the physical hardware resources and allocates them to multiple virtual machines running on the same host system.
Answer:
Virtualization was developed to solve problems such as:
Virtualization improved hardware utilization, reduced cost, and increased efficiency.
Before virtualization, traditional IT infrastructure had several limitations.
❌ Low Hardware Utilization
One server → One application
CPU usage only 10–20%
Remaining resources wasted
❌ High Hardware Cost
Each application required a separate physical server
More servers = higher investment
❌ High Power Consumption
More servers required more electricity and cooling
❌ Large Data Center Space
Physical servers require racks, cooling systems, and infrastructure
❌ Complex Maintenance
Hardware failures were common
Backup and recovery were slow and difficult
👉 Virtualization was introduced to solve these issues.
Virtualization became necessary for:
Example physical server:
With virtualization:
Multiple Virtual Machines share same hardware
Resource utilization increases to 70–80%
Without virtualization:
| Server Type | Physical Server |
|---|---|
| Web Server | 1 |
| Database Server | 1 |
| Mail Server | 1 |
| File Server | 1 |
👉 Total 4 physical servers
With virtualization:
All servers run as VMs on one physical server
Result:
Virtualization reduces:
Large organizations save significant electricity costs.
Without virtualization:
Buying new hardware takes days or weeks
With virtualization:
New VM can be created in minutes
Virtual machines can:
If a physical server fails → VMs can be restored quickly.
Cloud platforms like:
Use virtualization to provide:
👉 Without virtualization, → Cloud would not exist.
Without virtualization:
5 people → 5 separate cars
With virtualization:
5 people → 1 shared bus
👉 Better resource utilization.
Virtualization is not just a technology.
It is the backbone of modern IT infrastructure.
It:
