Two Fundamental Ideas of Computer Science: Algorithms and Information

1. Introduction

Almost everyone has used a computer at one time or another. Perhaps you have played computer games or used a computer to write a paper or make movies. Have you ever stopped to wonder what exactly a computer is? How can one device perform so many different tasks? These basic questions are the starting point for learning about computers and computer programming. A modern computer can be defined as “a machine that stores and manipulates information under the control of a changeable program.” There are two key elements to this definition. The first is that computers are devices for manipulating information. This means we can put information into a computer, and it can transform the information into new, useful forms, and then output or display the information for our interpretation. They are different from computers in that they are built to perform a single, specific task. This is where the second part of our definition comes into the picture: Computers operate under the control of a changeable program.

2. What is Computer Science?
A famous computer scientist named Edsger Dijkstra once quipped that computers are to computer science as telescopes are to astronomy. A computer is an important tool in computer science, but it is not itself the object of study. Since a computer can carry out any process that we can describe, the real question is What processes can we describe? Put another way, the fundamental question of computer science is simply What can be computed?
Computer scientists use numerous techniques of investigation to answer this question. The three main ones are design, analysis, and experimentation. One way to demonstrate that a particular problem can be solved is to actually design a solution.