KVM Explained: Differences Between Kernel-Based Virtual Machine and Keyboard, Video, and Mouse

When people mention "KVM," they could be referring to two completely different technologies, depending on the context: KVM (Kernel-Based Virtual Machine) or KVM (Keyboard, Video, and Mouse).

Many acronyms are shared by unrelated technologies, but in this case, Kernel-Based Virtual Machine and Keyboard, Video, and Mouse, while serving vastly different purposes, share a few similarities in application. This is likely why you're here, feeling a bit confused. Don't worry, this article will clear things up by exploring both types of KVM, highlighting their functions, similarities, and differences.

 

KVM (Kernel-Based Virtual Machine)

Overview: A Virtual Computer in the Linux Kernel

KVM stands for Kernel-Based Virtual Machine. It is a virtualization module within the Linux kernel that allows the kernel to function as a hypervisor. This means that multiple virtual machines (VMs) can run on a single physical machine, with each VM operating its own instance of an operating system (OS) in isolation, ensuring security and stability.

We’ll explain what a hypervisor is below.

 

Hypervisor

Imagine having a powerful computer at home, but instead of running just one operating system (like Windows or macOS), you want it to run several OSs simultaneously. For example, one part of the computer could run Windows, another Linux, and maybe another an older version of Windows.

To achieve this, you need something to manage your computer’s resources (CPU, memory, storage) and allocate them to these different operating systems. This is where the hypervisor comes in.

Think of a hypervisor as the manager or traffic controller of your computer. Just like a hotel manager assigns rooms to guests, a hypervisor assigns resources to each OS, ensuring they operate independently. Each OS behaves as if it’s running on its own machine, unaware of the others. In simple terms, a hypervisor lets your physical computer act like several separate computers, each capable of running its own operating system. This is the core of Kernel-Based Virtual Machine (KVM) technology.

KVM is just one type of virtual machine software. To help you understand better, we’ve compiled a list of common virtual machine solutions and their corresponding systems, showing that KVM (Kernel-Based Virtual Machine) is just one option among many.

  

Key Features of Kernel-Based Virtual Machine

Open-Source

As part of the Linux kernel, KVM is an open-source solution with a large community of contributors.

 

Performance

KVM offers near-native performance by leveraging hardware virtualization extensions like Intel VT or AMD-V.

 

Flexibility

It supports a wide range of guest operating systems, including various Linux distributions.

 

Scalability

KVM can handle multiple VMs, making it ideal for data centers and cloud environments.

 

Use Cases

• Server Virtualization: KVM is frequently used in data centers to run multiple servers on a single physical machine.

• Cloud Computing: Platforms like OpenStack utilize KVM for creating and managing virtualized environments.

 

KVM (Keyboard, Video, and Mouse)

Overview: Basic Hardware for Computer Control

In this context, KVM refers to Keyboard, Video, and Mouse. These are the essential hardware components needed to control a computer. With KVM devices, such as switches (common), extenders (common), matrices (common), and splitters (less common), you can manage multiple systems more efficiently. 

For more details on KVM hardware and its applications, you can refer to this article: What is KVM (Keyboard, Video, and Mouse), and How is it Used?

 

KVM Switch

A KVM switch is the most common type of KVM device. It consolidates the KVM (Keyboard, Video, and Mouse) connections of multiple computers into a single, simplified KVM setup. With one KVM, you can control four computers, saving on hardware costs and space. Typically, you can switch between computers using hotkeys or a control panel, deciding which one to manage at any given moment.

 

KVM Switch’s Multiviewer & Mouse Roaming Features

Some KVM switches allow you to control multiple computers simultaneously on a single screen, a feature known as Multiviewer. However, it’s not just about the visuals. With Mouse Roaming, you can move your mouse across the borders of the four computers' screens and seamlessly switch control between them.

 

KVM Extender

A KVM extender allows the KVM signal to be transmitted over long distances. Imagine a cashier’s computer at a bank. The main computer may store sensitive customer and financial data, which could be lost if the cashier accidentally spills coffee on the machine. To prevent this, the computer is placed in a secure data room, and a KVM extender enables the cashier to control it remotely.

 

Key Features of KVM (Keyboard, Video, and Mouse)

Hardware-Based

Unlike the Kernel-Based Virtual Machine, this type of KVM refers to a physical method of controlling computers.

 

USB and Video

Today’s KVMs use USB connections for keyboards and mice and video interfaces like HDMI and DisplayPort for display control.

 

Diverse Connectivity

KVM devices support various connections, including USB, HDMI, DisplayPort, and even audio channels.

 

Use Cases

• Data Centers: Administrators can manage multiple servers from a single or remote console, reducing the number of keyboards, mice, and monitors while enabling remote access to equipment housed in data rooms.

• Factories: These devices are used to control sensitive computers, allowing data to be protected while bypassing physical constraints.

 

KVM (Kernel-Based Virtual Machine) vs. KVM (Keyboard, Video, and Mouse): Similarities and Differences

Similarities

• Control Method: Both technologies are designed to manage multiple systems from a single point. The virtual machine KVM does this via software, while the hardware KVM uses physical connections.

• Efficiency: Both enhance efficiency by reducing the resources required to manage multiple or distant systems.

 

Differences

• Nature: KVM (Kernel-Based Virtual Machine) is software-based and handles virtualization at the operating system level, whereas KVM (Keyboard, Video, and Mouse) is hardware-based, facilitating the control of physical machines.

• Functionality: KVM (Kernel-Based Virtual Machine) focuses on creating and managing virtual environments, while KVM (Keyboard, Video, and Mouse) focuses on peripheral management across different physical computers.

• Applications: KVM (Kernel-Based Virtual Machine) is used in server virtualization and cloud environments, while KVM (Keyboard, Video, and Mouse) is more common in data centers and setups where multiple computers are controlled from a single station.

 

Conclusion

While both types of KVM share the same acronym, they serve very different purposes in the tech world. Understanding the distinction between them is crucial for IT infrastructure professionals, whether managing virtual environments or physical computers. Each type of KVM offers unique benefits and use cases, making them indispensable in their respective fields.