A virtual machine (VM) is a software-based mimic of a physical computer. It runs on a host system but functions as a standalone computer with its own operating system, storage space and computing power. You can run multiple virtual machines on a single physical machine, each with its own environment.
Virtual machines are enabled by virtualization software, also called a hypervisor. This hypervisor manages the hardware of the host system and distributes it among the different VMs. Thus, one physical server can serve as a platform for multiple virtual computers, each isolated from one another.
This separation allows you to run Windows on a Mac, for example, or use multiple operating systems side by side for testing purposes. This makes virtual machines popular in both the IT world and among individual users.
A virtual machine works by using a hypervisor, a layer of software that sits between the physical hardware (the host) and the virtual machines (guests). This hypervisor allocates resources such as CPU, memory, storage, and network capacity to each VM.
There are two main types of hypervisors:
Type 1 (bare-metal): runs directly on the hardware, with no operating system in between. Examples include VMware ESXi and Microsoft Hyper-V. These are often used in data centers.
Type 2 (hosted): runs on top of an existing operating system, such as Windows or macOS. Examples include VirtualBox and VMware Workstation. This type is often used for local testing.
When you start a virtual machine, the hypervisor emulates all the components a real computer has: a processor, memory, hard drive, network card, and so on. On top of that, you install an operating system of your choice (e.g., Linux or Windows). That operating system thinks it is running on a physical computer.
The host is the real physical system you're working on. The guest is the virtual machine running within that environment. The guest shares hardware resources from the host, but is isolated from it at the same time. If the guest crashes, it basically doesn't affect the host operating system.
This separation makes virtual machines ideal for experimentation, testing or running applications you'd rather not install directly on your main computer.
Virtual machines are used in a variety of situations, both by businesses and individual users. They offer flexibility, security and convenience in a variety of applications.
Developers use VMs to test applications on different operating systems without needing multiple physical devices. You can easily take snapshots, reproduce errors and reset systems.
Some older programs work only on legacy operating systems. A VM allows you to run Windows XP, for example, without modifying your current system.
A virtual machine is ideal as a secure testing environment. You can try out new software or suspicious files without risk to your host system. Does the VM get infected with malware? Then just throw it away and start over.
Companies can virtualize multiple servers on a single physical machine. This saves them on costs, space and energy consumption. One powerful server can host dozens of VMs, each fulfilling a separate role (such as Web server, mail server or database).
In the cloud, almost everything runs on virtual machines. Services such as Amazon Web Services (AWS), Microsoft Azure and Google Cloud offer virtual servers that you can start up, customize and scale in minutes.
Virtual machines are widely used in education, from high schools to universities. Students and scholars can practice installing and using operating systems without modifying their own laptops. In addition, they can test and use software through a VM, without having to download or install anything on their own device. This makes learning more secure, accessible and easier for school IT administrators to manage.
Virtual machines are also widely used to remotely access a digital work environment. There are three common technologies in this area:
VDI (Virtual Desktop Infrastructure): here, virtual desktops run on a central server, and users access their own virtual workspace over the network. This is widely used in organizations with many employees or flex workstations.
DaaS (Desktop as a Service): is similar to VDI, but as a cloud service. The infrastructure is managed by an external provider, providing less in-house maintenance and more flexibility. Consider services such as Windows 365 or Amazon WorkSpaces.
RDP (Remote Desktop Protocol): a Microsoft protocol that lets you connect to another computer over the network. You see and control the screen of a remote computer as if you were sitting behind it. RDP is often used to access an existing remote (virtual or physical) machine.
These technologies enable secure, flexible and location-independent working whether you're in education, healthcare or managing a business environment.
There are two main types of virtual machines, each with its own purpose and operation. It's important to know the difference, especially when choosing which technology best suits your situation.
A system virtual machine simulates a full physical computer. It runs a full operating system and functions like a real PC or server. This type is most commonly used, for example, to run Windows on a Mac, or to host multiple servers on a single physical machine. Examples of software that make this possible include VirtualBox, VMware and Hyper-V.
Features:
Runs a complete OS
Uses a hypervisor
Suitable for testing, server virtualization and cloud environments
A process virtual machine runs only one program or process, and disappears once the program is closed. Instead of simulating an entire operating system, it provides a virtual environment in which an application can run. A well-known example is the Java Virtual Machine (JVM), which allows Java programs to run platform-independently.
Characteristics:
Runs a single process
Requires fewer resources
Suitable for platform-independent software
Behind virtual machines are several techniques that determine how the virtual environment is set up and managed. Each technique has its own applications, advantages and limitations. Below we discuss the three most commonly used forms.
In full virtualization, a computer's hardware is completely mimicked. The operating system in the VM thinks it is running directly on physical hardware, while in reality everything is managed by a hypervisor.
Advantages:
Flexible: any operating system can be installed
No modifications needed to the guest operating system
Disadvantage:
Slightly heavier on the host because all hardware must be simulated
This form is similar to full virtualization, but uses special features in modern processors (such as Intel VT-x or AMD-V). These features help the hypervisor work more efficiently.
Advantages:
Faster performance than full virtualization
Better support from modern CPUs
Disadvantage:
Requires support in host hardware
OS-level virtualization involves running a single operating system kernel, and creating multiple isolated user environments (containers) within that same OS. Well-known examples are Docker and LXC.
Advantages:
Disadvantage:
Less flexible: you can only run systems using the same OS as the host
Containers are often compared to virtual machines. They are ideal for application development and microservices, but offer less isolation than a traditional VM.
Virtual machines offer many advantages, both technical and practical. This makes them popular in IT environments, development teams and even among individuals experimenting with software or systems.
By running multiple virtual machines on a single physical server, you save on hardware costs. This is especially interesting for companies that would otherwise need multiple servers.
You can quickly set up new environments, switch operating systems or test software without modifying your real system. This speeds up development and testing processes.
Each VM runs completely isolated from other VMs and from the host. This means that errors, crashes or malware in one VM do not affect other systems.
VMs are easy to copy, move or clone. This allows you to easily scale up or adapt your infrastructure to changing needs, such as in a cloud environment.
Virtual machines make it possible to run different operating systems side by side on a single machine. Think Windows, Linux and macOS side by side, for cross-platform development, for example.
Although virtual machines offer many advantages, there are also some disadvantages and limitations to consider. In some situations, another solution, such as containers, may be a better fit.
Because a VM uses additional layers of software to emulate hardware, it usually performs slightly slower than a system running directly on physical hardware. You notice this difference especially with heavy graphics applications or high I/O loads.
Managing multiple VMs can get complicated, especially when dealing with snapshots, updates, network configurations and storage. Larger environments often require additional management tools.
VMs have limited direct access to hardware. This can cause problems with USB devices, GPU acceleration or custom peripherals, for example. While workarounds exist, it is not always as smooth as on a physical system.
Virtual machines provide powerful features for management and business continuity. Three commonly used functionalities are snapshots, migration and failover. These help with backups, maintenance and high availability.
A snapshot is a snapshot of the status of a VM at a given time. Consider a backup of the entire system, including memory, settings and disk contents. You can take a snapshot before running updates or tests, so you can always revert to the previous state if something goes wrong.
Applications:
Securely test software
Quickly roll back updates
Create temporary environments
Migration involves moving a running VM from one physical host to another, sometimes even without interruption. This is also known as live migration.
Benefits:
Perform maintenance without downtime
Balancing workloads across multiple servers
Efficient use of hardware
In failover, a VM is automatically taken over by another host if the original one fails. This is a form of high availability and is often used in conjunction with clustering and replication.
Situations in which failover is useful:
Server failures
Hardware failures
Emergency recovery
These features make virtual machines not only flexible, but also reliable for critical applications.
Virtual machines and containers are often mentioned in the same breath, but they are fundamentally different technologies. Both provide isolation and flexibility, but the way they do so differs greatly.
A container is a lightweight virtual environment that runs on top of the host operating system. Unlike a VM, a container does not have its own operating system, but shares the host's kernel. Well-known tools include Docker and Kubernetes.
Key differences
| Feature | Virtual machine | Container |
|---|---|---|
| Proprietary operating system | Yes | No |
| Boot time | Slow (several minutes) | Fast (seconds) |
| Resources | Heavier | Lightweight |
| Isolation | Strong (hardware-based) | Weaker (shared kernel) |
| Use | OS virtualization | Application virtualization |
| Suitable for | Multiple OSes, legacy systems | Microservices, scalable apps |
Virtual machines are appropriate when you need complete system isolation, want to run different operating systems or support legacy software.
Containers are ideal for modern applications, CI/CD pipelines and scalable microservices, especially when speed and efficiency are important.
In practice, VMs and containers are often used together. For example, running multiple containers within a VM in the cloud, taking advantage of both technologies.
Setting up a virtual machine today is easy and does not require advanced technical knowledge. With the right tools and settings, you'll have a working VM running on your computer within minutes.
Before you start, make sure you have:
A stable computer with sufficient memory (at least 8 GB RAM) and storage space
A virtualization software such as:
VirtualBox (free, open source)
VMware Workstation Player (free for non-commercial use)
Microsoft Hyper-V (built into Windows Pro)
An operating system image (ISO file) of, for example, Windows, Ubuntu or another Linux distribution
Roadmap
Download and install virtualization software
Go to the tool's official website (e.g. virtualbox.org) and install the software.
Create a new VM
Open the software and choose “Create new machine. Enter a name, select the desired OS and allocate memory.
Attach the ISO file
Attach the downloaded installation file as a boot disk so that the VM can boot from it.
Configure settings
Choose how much RAM and storage you want to allocate. You can also set up network settings or shared folders later.
Start the VM and install the operating system
The VM starts from the ISO file. Follow the installation instructions of the chosen OS, just like a real computer.
Install any additional tools (such as Guest Additions with VirtualBox)
This will improve integration between the host and guest, such as better screen resolutions, shared clipboard and file drag and drop.
After installation, you can use your virtual machine as if it were a separate computer.
Virtual machines are a powerful tool for those who want to work flexibly, securely and efficiently with software and systems. They make it possible to run multiple operating systems side by side, without additional physical devices. Whether you want to test software, keep legacy applications running, provide secure learning environments for students, or scale your IT infrastructure; virtual machines provide the solution.
Thanks to virtualization software, VMs are accessible to beginners and professionals alike. Moreover, the technology continues to evolve, with combinations with containers and cloud platforms providing even more possibilities. Virtual machines are and will continue to be an indispensable part of modern IT.
A virtual machine is a virtual computer that runs inside a physical computer. It has its own operating system and operates separately from the host's system.
Yes, there are several free tools available, such as Oracle VirtualBox and VMware Workstation Player (for non-commercial use).
Yes, you can. As long as your PC has sufficient memory, storage space and processing power, and virtualization is enabled in the BIOS, you can run a VM.
Virtual machines are used for software testing, running old programs, educational purposes, secure test environments, server consolidation and cloud computing.
