How a Virtual Machine Works

[chushpan]

What is a virtual machine (VM)?​

A virtual machine (VM) is a software or hardware environment that emulates the operation of a real computer. It allows you to run operating systems and applications in an isolated environment that is independent of the main (host) hardware. Virtual machines are widely used for software testing, development, server creation, and security.

How does a virtual machine work?​

The operation of a virtual machine is based on virtualization technology, which allows you to create several isolated systems on one physical device. Here are the main stages of operation:

1. Hypervisor​

A hypervisor is a key component that manages virtual machines. It acts as an intermediary between the physical hardware (host) and the virtual machines (guests).

There are two types of hypervisors:

• Type 1 (Bare-metal): Installed directly on bare metal (e.g. VMware ESXi, Microsoft Hyper-V).
• Type 2 (Hosted): Runs as an application on a host operating system (e.g. VirtualBox, VMware Workstation).

The hypervisor distributes resources (processor, memory, disk space) between virtual machines.

2. Creating a virtual machine​

1. Setting parameters:
   • The user determines the number of processor cores, the amount of RAM, the size of the hard drive and other resources.
2. OS installation:
   • An operating system (e.g. Windows, Linux) is installed on the virtual machine.
3. Insulation:
   • Each virtual machine operates independently of others, even if they are running on the same host.

3. Hardware emulation​

1. Virtual hardware:
   • The hypervisor provides the virtual machine with access to emulated hardware (processor, video card, network card, etc.).
2. Drivers:
   • Virtual machines use special drivers (such as VMware Tools or VirtualBox Guest Additions) to improve performance.

4. Executing commands​

1. Processing instructions:
   • Commands sent by the operating system inside the virtual machine are passed to the hypervisor.
2. Transfer to physical equipment:
   • The hypervisor executes these commands on the actual host hardware.

5. Isolation and safety​

1. Isolated environment:
   • The virtual machine runs in its own environment, which prevents conflicts with other systems.
2. Safety:
   • Even if the virtual machine is hacked, the attacker will not be able to access the host system.

Example of a virtual machine in operation​

Scenario: Testing new software​

1. The developer wants to test a new version of the program on different operating systems.
2. It creates multiple virtual machines with different OS (eg Windows 10, Ubuntu, macOS).
3. Each virtual machine runs independently, and the developer can install and test the program without the risk of damaging the main system.

Advantages of Virtual Machines​

1. Efficient use of resources:
   • Multiple virtual machines can run on a single physical server, saving hardware.
2. Insulation:
   • Virtual machines are isolated from each other, which reduces the risk of conflicts.
3. Flexibility:
   • Easily create, clone and delete virtual machines.
4. Testing and development:
   • Ideal for testing new programs, updates and experiments.
5. Safety:
   • Viruses or bugs inside the virtual machine do not affect the host system.

Disadvantages of Virtual Machines​

1. Performance:
   • Virtualization adds overhead that can slow things down.
2. Host resources:
   • Running multiple virtual machines requires powerful hardware.
3. Licensing:
   • Some operating systems and programs require additional licenses to use in virtual machines.

How to create a virtual machine?​

Steps using VirtualBox (example):​

1. Download VirtualBox:
   • Download and install VirtualBox from the official website.
2. Create a new virtual machine:
   • Click "New" and specify the name, OS type and memory size.
3. Configure your hard drive:
   • Create a virtual hard disk (VHD) to store data.
4. Install the operating system:
   • Mount the ISO image of the operating system and follow the installation instructions.
5. Set up the parameters:
   • Configure network adapters, connect devices and install drivers.
6. Start the virtual machine:
   • Click "Start" to launch.

Conclusion​

A virtual machine is a powerful tool for testing, developing, and creating isolated environments. It allows for efficient resource utilization, provides security, and simplifies the management of multiple systems. However, it is important to consider performance limitations and hardware requirements.

If you have additional questions about how virtual machines work or how to use them, please ask!

 

[Man]

A virtual machine (VM) is a software emulation of a physical computer that allows you to run multiple isolated operating systems (OS) on a single physical device.

1. Main components​

Component	Description
Host machine	The physical computer on which the VM is running (for example, your laptop).
Hypervisor	Software that creates and manages VMs (VMware, Hyper-V, VirtualBox).
Guest OS	The operating system running inside the VM (Windows, Linux, etc.).
Virtual resources	CPU, RAM, disk and network allocated to VM.

2. Operating principle​

2.1. The role of the hypervisor​

A hypervisor is a layer between physical hardware and virtual machines. It comes in two types:

• Type 1 (hardware): Works directly on hardware (ESXi, Hyper-V). Used in servers.
• Type 2 (host): Runs as a program on the host OS (VirtualBox, VMware Workstation).

2.2. Resource Allocation​

• The hypervisor distributes host resources (CPU, RAM, disk space) between VMs.
• For example, if you have 16 GB of RAM, you can allocate 4 GB to the VM and leave the rest to the host OS.

2.3. Insulation​

• Each VM operates independently of the others.
• A failure in one VM does not affect the others.

3. Examples of use​

Scenario	Example
Software testing	Running malicious code in an isolated environment.
Servers	Hosting multiple web servers on one physical server (VPS).
Development	Running Linux on Windows for cross-platform development.
Bypassing blockages	Launching the OS with a different IP (for example, via VPN in VM).

4. Pros and cons​

✔ Pros​

• Save hardware: No need to buy separate computers.
• Security: Viruses in VM will not affect the main system.
• Flexibility: You can quickly create, copy and delete VMs.

✖ Cons​

• Performance: VM is slower than physical machine (due to overhead).
• Resource requirements: For comfortable operation, you need to allocate enough CPU/RAM.

5. How to create a virtual machine?​

1. Install a hypervisor (eg VirtualBox).
2. Create a new VM:
   • Specify the name, OS type (Linux, Windows).
   • Allocate resources (RAM, CPU, disk).
3. Download the OS image (ISO file) and install the system.
4. Launch the VM and work in it as on a regular PC.

Conclusion​

1. A virtual machine is a "computer within a computer".
2. The hypervisor manages resources and isolates VMs.
3. Used for testing, servers and secure web surfing.

Want to try it? Install VirtualBox - it's free and easy!