To maximize efficiency and minimize cost, purchasing departments are using computers to issue purchase orders, expedite orders, and control inventory. In order to familiarize prospective users, explanations of some of the terminology, equipment, and other pertinent facts associated with automation are supplied. Six pages, in outline form, explain computer systems, hardware, software, components, and how the computer works. General information (configuration, capabilities, applications, maintenance, operation, equipment availability, cost, and vendors) is presented about microcomputers, minicomputers, and maxicomputers. (MLF)