VMware ESX is the building foundation of
VMware vSphere 4. Unlike
VMware Server, VMware ESX is designed to run directly on physical servers. VMware ESX is a high performance virtualization hypervisor, which enables servers to run multiple virtual machines concurrently.
Each virtual machine represents a complete operating system with its own CPU, memory, network, storage and BIOS. Sharing the physical server resources among a number of virtual machines increases hardware utilization and dramatically decreases capital cost.
