A mainframe is a large-capacity computer system with processing power that is significantly superior to PCs or midrange computers. Traditionally, mainframes have been associated with centralized, rather than distributed, computing environments. Skilled technicians are required to program and maintain mainframes, although client/server technology has made mainframes easier to operate from the user’s and programmer’s perspectives. They are generally used by large organizations to handle data processing for enterprisewide administrative tasks like payroll or accounts payable.