Hardware virtualization using hypervisors
Virtual machines (VMs) are software emulations of physical computers that run operating systems and applications. VMs are created and managed by hypervisors (virtual machine monitors) that abstract physical hardware and provide virtualized resources to guest operating systems. There are two types of hypervisors: Type 1 (bare-metal) runs directly on hardware (e.g., VMware ESXi, Microsoft Hyper-V, Xen), and Type 2 (hosted) runs on top of a host operating system (e.g., VMware Workstation, VirtualBox). VMs provide strong isolation between guest systems, allowing different operating systems to run simultaneously on the same physical hardware. Key VM concepts include virtual hardware (virtual CPUs, memory, storage, network interfaces), snapshots (point-in-time copies of VM state), migration (moving VMs between physical hosts), and resource allocation (CPU, memory, I/O limits). VMs are widely used for server consolidation, development and testing, legacy application support, and cloud computing infrastructure. Understanding VM technology is essential for system administrators, cloud engineers, and anyone working with modern data center environments.