What a virtual machine is
A virtual machine, or VM, is a computer created entirely in software that runs inside a real, physical computer. It behaves like a separate machine with its own operating system, memory, and storage, even though it is really just a program running on the host. This lets you run a whole other computer, such as Linux on a Windows PC, in a window, without buying any new hardware.
How it works
A VM is made possible by software called a hypervisor, which divides a physical computer's resources, its processor, memory, and storage, and allocates a share to each virtual machine. The hypervisor keeps each VM isolated from the others and from the host, and tricks the operating system inside each VM into believing it has a real computer all to itself. Several VMs can run on one physical machine at once.
Why they are useful
Virtual machines offer flexibility and safety. You can run software that needs a different operating system, test risky programs in an isolated VM where they cannot harm your real system, and run several separate environments on one computer. Because a VM is just files, it can be copied, backed up, moved to another machine, or reset to a clean state in moments, which is invaluable for developers and IT teams.
Virtual machines and the cloud
VMs are the backbone of cloud computing. When you rent a server from a cloud provider, you are usually renting a virtual machine running on their vast physical hardware. This lets providers divide powerful computers among many customers efficiently and lets customers create or shut down servers in minutes, paying only for what they use. Virtualization is what made the flexible, on-demand cloud possible in the first place.
Virtual machines versus containers
VMs are often compared with containers, a lighter alternative. A VM includes a full operating system, which makes it strongly isolated but relatively heavy and slow to start. A container shares the host's operating system and packages just an application and its dependencies, making it far smaller and faster, though less isolated. Many modern systems use both: VMs for strong separation and containers for efficient, portable applications on top.
The bottom line
A virtual machine is a complete, software-based computer running inside a physical one, made possible by a hypervisor that shares out real hardware. VMs let you run other operating systems, isolate risky software, and power the cloud, all without extra machines. Understanding them, and how they differ from lighter containers, explains much of how modern computing and cloud services are built.
Related on Skillo
See also: What is serverless computing? Explained, What is Docker? Containers explained for beginners.
Sources
Published date reflects the original event date (2026-10-23). This article is original Skillo editorial written from the sources above; facts were verified in September 2026.
Leave a Reply