VMware ESX and VMware ESXi install directly on the server hardware, inserting a robust virtualization layer between the hardware and the operating system. VMware ESX and ESXi partition a physical server into multiple secure and portable virtual machines that can run side by side on the same physical server. Each virtual machine represents a complete system—with processors, memory,networking, storage and BIOS—so that an operating system and software applications can be installed and run in the virtual machine without any modification. Virtual machines are also completely isolated from each other by the virtualization layer, thus preventing a crash or configuration error in one virtual machine from affecting the others. Sharing the physical server resources among a number of virtual machines increases hardware utilization and dramatically decreases capital costs. The bare-metal architecture gives VMware ESX and ESXi complete control over the server resources allocated to each virtual machine and provides for near-native virtual machine performance and enterprise-class scalability. VMware ESX and ESXi provide virtual machines with built-in high availability, resource management and security features to deliver improved service levels to software applications than static physical environments.