What Is Virtualization? Uncover How Cloud Computing Really Works

This article introduces the basics of virtualization and cloud computing, emphasizing why asking "why" fosters proactive learning.

1. Concepts

What is virtualization and cloud computing? Cloud computing is a pay‑as‑you‑go model, while virtualization means creating a simulated version of physical hardware.

What is the relationship between cloud computing and virtualization? Cloud computing is realized through virtualization technology; virtualization is a technique, and cloud computing is an operational model.

2. Computer Virtualization

Virtualization creates a virtual representation of physical hardware. To understand how a computer virtualizes hardware, recall the computer’s structure: input devices, output devices, controller, processor, and memory. The controller and processor form the CPU, while memory includes RAM and storage. An operating system is installed on the hardware, followed by application software.

Experiment Goal

Use a physical computer to virtualize another computer.

Thought Process

First, verify whether the hardware supports virtualization, then choose appropriate software.

Hardware Check

Focus on the CPU. In Windows, tools like CPU‑Z show VT‑X support for Intel and universal support for AMD. In Linux, the command # cat /proc/cpuinfo displays flags indicating virtualization capability.

CPU and Operating System

CPUs have privilege levels: 0 (kernel mode), 1 and 2 (unused), and 3 (user mode). The operating system abstracts hardware resources and provides services to applications. It consists of a kernel that interacts directly with hardware and a shell that offers user‑level interfaces.

Abstraction means modularizing hardware functions so applications can request services without dealing with hardware directly, enhancing safety.

When a user program needs kernel services, it uses system calls or library functions to communicate with the kernel.

Example: a user asks “1+1=?”; the request passes through the operating system to the hardware, which computes the result and returns it to the user via the shell.

In the next article we will discuss software that implements virtualization.