This document provides an introduction to computers, including:
1. It defines a computer and outlines its history from early counting aids to modern programmable computers.
2. It identifies important characteristics of computers like speed, accuracy, storage, and versatility.
3. It describes the main types of computers based on operational principles and size - analog, digital, hybrid, microcomputers, minicomputers, mainframes, and supercomputers.
4. It gives examples of applications of computers in various fields like healthcare, business, banking, education, engineering and more.