Servers are generally comprised of a rackmount chassis that houses a power supply, a system board, one or more CPUs, memory, storage, a network interface, and a power supply. Out-of-band administration is supported by most server hardware through a dedicated network port. In addition, some form of remote management technology is typically required for server maintenance. The world's first commercial computer was the ENIAC, built by the U.S. Army during World War II. It had over 18,000 parts contained in six large rooms. The term "server" wasn't used then for what we think of it today; it referred to an electrical circuit that would take information from telegraph wires and transmit it back again at a different frequency. The first actual server device was developed shortly after the war by IBM and consisted of a mainframe computer with its own power supply and storage devices. They were installed in restaurants to perform tasks such as payroll and bookkeeping. Since then, servers have become smaller and more powerful, allowing them to be placed in many different locations with ease. Some large organizations have multiple data centers - separate facilities - with their own power supplies and climate control systems where their servers can be housed. Other organizations may have one central data center where all their servers are located. There they share power supplies and cooling systems with other equipment.