VMware Server requires an underlying operating system like Windows Server 2003 but has no hypervisor. It has its own virtual switch and is fairly secure for single server installs. ESXi has a hypervisor so no underlying OS is needed, and it has better fault tolerance, faster recovery, and allows for higher server consolidation compared to VMware Server. Storage area networks provide faster connectivity than traditional setups, use less cabling and equipment, and offer redundancy and cost efficiency over traditional networking. Cloud computing optimizes infrastructure for virtualization, allows outsourcing of maintenance, consolidation of data and voice services, and reduces costs, carbon footprint and improves security compared to traditional IT systems.