Historically, mainframe -sized computers have been enterprise servers although they were not referred to as servers until recently. As smaller, usually UNIX -based server and Wintel computers have become faster and been provided with enterprise-wide program management capabilities, they have been referred to as enterprise servers. In this usage, an enterprise server is both the computer hardware and its main software, the operating system. Some companies use enterprise servers to describe a “super program” that runs under the operating system in a computer and provides services for the system administrator and for the business application programs and more specialized servers that run in the computer. Before this usage originated, such services were sometimes considered part of the operating system itself or came in separate software packages.
Originally, many services provided by an enterprise server tended to be available only on IBM or similar mainframe computers while less powerful computers ran specialized applications.