In the third period, the integrated circuit(IC) that is a complete electronic circuit that packages transistor(signal bridges) and other electronic components on a small silicon chips, replaced traditional transistorized circuity. Integrated circuits are cost-effective because individual components don’t need to be directly to the computer’s system board. The use of magnetic disk for secondary data storage become widespread, and computers began to support such capabilities as multiprogramming and timesharing. Minicomputers,priced around $18000, were being widely used by the early 1970s and were taking some of the business away from the estabilished mainframe market. Processing that formerly required the processing power of a mainframe could now be done on a minicocomputer.