Virtualization uses programs to create a virtual machine (VM) that simulates a physical computer. This creates a separate operation that is logically isolated from the hosting server. Providing multiple VMs simultaneously, this approach allows multiple operating systems to run on one physical machine at a time. Instead of paying for multiple malfunctioning service devices, each dedicated to a specific workload, server virtualization allows you to centralize those workloads into smaller fully utilized physical machines. Microsoft (Hyper-V) and VMware provide programs to facilitate this process.