In Linux, many times, you want to find out the PID of a process which is listening on a port e.g. if multiple apache(httpd) servers are running on a host then, how do you find the PID of the apache(httpd) listening on port 8080?
KVM (Kernel-based Virtual Machine) is, on the other hand a full virtualization solution for Linux containing virtualization extensions (Intel VT or AMD-V). Using KVM, one can have Linux and Windows virtual machines running side by side on the same hardware. Each virtual machine has private virtualized hardware: own kernel, a network card, disk, graphics adapter, etc. Since it has its own virtualized hardware, the virtual server will act completely on its own.