virtual machine is defined as software of a computer which provides the functionality similar to the physical computers for example they run operating system and applications on top of it but they differ from the physical computer and the fact that they are computer files known as an image which runs on top of physical computers using the hypervisor due to this the user has the liberty of running multiple operating systems on top of the main operating system without the need of buying additional physical resource a virtual machine is a computer file usually known as an image that acts like a real computer this means that a computer is created inside a computer it works in a window like any program providing the end user with the same virtual system experience on the host operating system from the rest of the system it is sandboxed so the program cannot escape from or tamper with the device itself within the virtual machine this creates the ideal environment to test operating systems other than access virus data beta releases or run operating system software or create operating system backups apps for which they have not been originally designed many virtual machines can run on the same physical computer simultaneously for servers several operating systems run side by side with the software known to be managed as a hypervisor whereas desktop computers normally run other operating systems in their program windows by using one operating system each virtual machine has its own virtually exclusive hardware including hard drives cpus network interfaces memory and other hardware the virtual hardware is then mapped to the actual hardware on the physical computer which decreases cost and the related maintenance costs by reducing the need for physical hardware systems as well as power and replacing demand virtualization technology can share a network with a large number of virtual environments the hypervisor controls and removes the hardware from the virtual environment assets are segregated from the physical surroundings to the virtual machine as appropriate if a virtual machine is running the hypervisor programmed the resource request for the physical system so that the operating system and applications of the virtual environment can have access to the combined pool of physical resources which requires additional resources from the physical environment there are two types of hypervisors a hypervisor type 1 is built on bare metal virtual machine resources are directed by the hypervisor to the hardware kvm is a hypervisor type 1 example hosted is type 2 of the hypervisor virtual machine resources are programmed against a host operating system and run against the hardware examples of type 2 hypervisors include vmware workstation and oracle virtualbox once we know this when opening a virtual machine such as virtualbox we have an environment in which we can configure and resource each physical component that is emulated by it space we want our hard drive to assign ram memory we want the virtual machine to allocate the network settings we want we have created a virtual machine for installing a working system after configuring the parameters this means we only have to open and install it which has just been created as if it was a normal computer the consolidation of servers is a major reason for using vms many operating systems and device implementations use a small number of the available physical resources to bare metal you can place many virtual servers on each physical server by virtualizing your servers to improve hardware usage you don't need to buy additional physical resources and minimize the need for power space and cooling in the data center vms allow failover and redundancy which can only be done previously by additional hardware a vm offers an environment isolated from the rest of a device and so anything running on the host hardware will not interfere since vms are isolated they are a good way to test or build a development environment for new applications even to support a specific process you can run a single vm advantages provide solutions for disaster recovery and implementation digital computers are managed maintained and accessible in general a single physical computer can run multiple operating system environments disadvantages running more than one virtual machine can lead to an unstable output it is less efficient and slow running than a physical machine