5.) Mainframe: this is a very large and expensivecomputer capable of supporting thousandsof users at the same time. For this reason, itis used in businesses and it's the centre ofcomputer networks. These super computers,which are usually as big as a large refrigerator,are the most powerful and expensive ones andthey're used for jobs which require enormousamounts of calculations, such as weatherforecasting, engineering design and economicdata processing.