In computing, a virtual machine is an emulation of a computer system. Virtual machines are based on computer structures and provide the functionality of a physical computer. Their implementations may involve specific hardware, software, or a blend.
A virtual machine is a computer file, typically called an image, which behaves like an actual computer. In other words, building a computer within a computer. It runs in a window, much like any other program, giving the end-user the same practice on a virtual machine as they would have on the host operating system itself. The virtual machine is sandboxed from the rest of the system, betokening that the software inside a virtual machine cannot evade or tamper with the computer itself. This produces an exemplary environment for testing other operating systems including beta releases, obtaining virus-infected data, creating operating system backups and running software or applications on operating systems for which they were not originally assigned.
Multiple virtual machines can run concurrently on the same physical computer. For servers, the multiple operating systems run side-by-side with a piece of software called a hypervisor to manage them, while desktop computers typically operate one operating system to run the other operating systems within its program windows. Each virtual machine provides its virtual hardware, including CPUs, memory, hard drives, network interfaces, and other devices. The virtual hardware is then drafted to the real hardware on the physical machine which saves costs by reducing the need for physical hardware systems along with the associated subsistence costs that go with it, plus reduces power and cooling demand.
Uses of Virtual Machine:
- Ever need to try something on a Linux machine from your Windows computer, but didn’t have any access to a remote Linux machine via SSH? Kick off a Linux VM.
- Same as 1, except replace Windows with Linux, Linux with Windows, and SSH with RDP.
- Ever have a powerful server and have a bunch of smaller, less powerful machines you wish you could run on it? Setup a type 1 hypervisor, and kick off some VMs.
- Ever have a bunch of older servers running various things (DNS, DHCP, NTP, AD, database, etc.) and not enough space in your server rack for everything, consider something like 3, and get a powerful machine to run VMs of each of the servers.
- Ever have a demo kit that you need to send with a non-technical person but requires a series of complex server and networking configurations? Set up some VMs they can just start on a laptop they take with them.
How does the virtual machine work?
Defining the precise operation of a virtual machine is very intricate and that few people have the necessary knowledge to do it. However closely we can say that a virtual machine is a software that through a layer of virtualization corresponds with the hardware that we have available in our computer thus getting emulate all the elements of a real computer. In this way, the virtual machine will be able to emulate a hard disk, a RAM, a network card, a processor, etc.
Once we know this when we open a virtual machine, such as a Virtual box, we have a graphical atmosphere that will allow us to configure and commit resources to each of the physical components that the virtual machine emulates. So for example in virtually all virtual machines we must define details of the following type:
- Space that we want to assign to our hard drive.
- RAM that we want to assign to the virtual machine.
- The memory of our graphic card.
- The network configuration that we want.
Once these parameters are configured, we will have created a virtual machine to install an operating system. In this way, we will only have to open the virtual machine that has just been created and install the operating system as if it were a real normal computer.
The main advantages of virtual machines:
- Multiple OS environments can exist simultaneously on the same machine, isolated from each other;
- A virtual machine can offer an instruction set architecture that differs from real computer’s;
- Easy maintenance, application provisioning, availability and convenient recovery.
The main disadvantages:
- When multiple virtual machines are simultaneously running on a host computer, each virtual machine may introduce an unstable performance, which depends on the workload on the system by other running virtual machines;
- The virtual machine is not that efficient as a real one when accessing the hardware.
Best Free Virtual Machine Software for Windows and Mac
- VirtualBox (Mac & Windows)
- VMware Workstation Player (Windows, Linux)
- VMware Fusion (Mac)
- Parallel’s Software (Mac)
- Hyper-V (Windows)
VMware Infrastructure implements a simple architecture in the virtual environment to allow companies to manage computing, storage, and networking resources without worrying about the underlying physical hardware. VI architecture allows businesses to create and configure their datacenters and reallocate resources to different pre-eminence without the time delay and cost of reconfiguring their physical hardware infrastructure.
With a suite of companion virtualization and management services, such as VMware VMotion, VMware DRS, VMware HA, and VMware Consolidated Backup, VMware Infrastructure is the only product that provides a comprehensive solution rather than a gradual approach to building data centers in the virtual environment.