The document discusses different classifications of computers based on their nature, purpose, and size over different generations. It covers:
1) Classifications by nature include digital, analog, and hybrid computers. Digital computers use binary digits while analog uses physical properties.
2) Classification by purpose includes special purpose designed for specific tasks, and general purpose for a variety of problems.
3) Classification by size discusses mainframe, minicomputers, and microcomputers where microcomputers are for individual use with processors on a chip.