[1] Introduction To Virtualization

A running program executes instructions, with the processor fetching an instruction from memory, decoding it, and executing it millions or even billions of times per second. It continues this process until the program completes, which describes the basics of the Von Neumann model of computing. Sounds simple, right? In this series, we'll learn that while a program runs, many other things happen to make the system easy to use..

There is a software responsible for making it easy to run programs (even allowing you to run many programs at the same time), letting programs share memory, enabling them to interact with devices, and other useful tasks. This software is called the operating system (OS), as it ensures the system operates correctly and efficiently in an easy-to-use way.

In the world of computing, an operating system’s primary role is to takes a physical resource (like the processor, memory, or a disk) and changes it into a more general, powerful, and easy-to-use virtual version and provide a convenient environment for software to run. One of the most critical tasks an OS performs is virtualization—the process of creating a virtual version of a resource, such as the CPU or memory, that allows multiple applications to run as if they each have the computer’s full resources to themselves. This piece explores how the OS achieves this illusion, ensuring that each program believes it is running on its own dedicated machine, despite sharing resources with many others. By abstracting and managing resources, the OS not only maximizes efficiency but also ensures fairness and security among processes.

What key concepts or skills should you expect to have mastered by the end of this series?

1. The Purpose of Virtualization.

   • Why Virtualization Matters: Understand why operating systems use virtualization to efficiently manage hardware resources and provide an isolated environment for each process.

   • Resource Sharing: Grasp how virtualization allows multiple processes to share the same hardware without interfering with each other.

2. CPU Virtualization.

   • Process Scheduling: Learn how the OS manages multiple processes, giving each one a slice of CPU time to create the illusion of parallel execution.

   • Context Switching: Understand the concept of context switching, where the OS saves the state of one process and loads the state of another to switch between processes seamlessly.

   • Privileged Instructions: Know the difference between user mode and kernel mode, and how the OS controls access to critical hardware resources.

3. Memory Virtualization.

   • Virtual Memory: Comprehend how the OS uses techniques like paging and segmentation to give each process its own virtual address space.

   • Address Translation: Understand how the OS translates virtual addresses used by processes into physical addresses in memory.

   • Protection and Isolation: Learn how virtualization provides memory protection, ensuring that one process cannot access or corrupt the memory of another.

4. Security and Efficiency.

   • Security Implications: Recognize the role of virtualization in enhancing system security by isolating processes and preventing them from accessing unauthorized resources.

5. Efficiency Trade-offs: Understand the performance implications of virtualization and how the OS balances efficiency with the need for isolation and security

6. Real-world Applications.

   • Use Cases: Be aware of practical examples of virtualization, such as in virtual machines and containerization, where these concepts are applied in modern computing environments.