Chapter Summaries

If you would like to save a million dollars, here's how. You need to deposit just the right amount each month at just the right interest rate for the right number of years. And you will have it. Let's write a program that will fill in the blanks in this calculation. This chapter shows you how to do numerical calculations of this kind the easy way, by letting a computer do the work. You will study functions here that might represent any quantity that you might be interested in: space in your new house, profits from your yard sale, or the expected number of votes for your candidate in the next election. Then you will learn how to find optimize your decisions to get the best results.

Who murdered Lord Peter Dunsmore on a sunny afternoon at the famous Dunsmore Manor? You need to get all the facts and deduce the answer. The method for doing it will be to program a database to hold all of the facts and then to query the database to try to solve the mystery. You get to learn how to attack a sizeable programming problem and you get to use your skills to solve the mystery. This chapter discusses the main techniques in computer science for solving complex problems and illustrates the points in the solution to the database problem. You will also learn the fundamental principles of relational databases and how they work.

By now you have learned a lot about programming Java and this chapter gives you a chance to enjoy and explore those skills. You learn here how to draw a line or an arc on the computer screen and how to color things and suddenly you can draw any picture that you can imagine. You read this chapter and do the programming just for the fun of it.

Suppose you want to observe something but you cannot because it is too expensive or too slow or just impossible to observe. You will be able to get your wish if you can successfully simulate that thing. This means you discover a model for that thing and then program it into a machine. Then you run the model and do your observation. If your model is good, you will be able to see what would have happened with the original problem if you had been able to observe it. In this chapter, we will study how to win a car race by working with a simulation of it. Then we will study disease contagion, evolution, and impossible-to-imagine shapes by using simulation.

Now that you have experienced some programming, you may have the feeling that you can program anything. For example, you might decide to write a large program and then organize all of your friends to write parts of it. You could combine all of their assigned parts and put together a really ambitious project. It turns out that writing larger programs is much harder than writing small ones. In fact, even experienced professionals have been fooled on many occasions in estimating what they could do in writing large programs. So a field called "software engineering" evolved which addresses this surprisingly difficult problem.

When you bought your new machine at the computer store, what did you actually get? In fact, you received hardware that executes machine instructions in the "fetch-execute cycle" at a very high speed, some memory, and other devices. This chapter tells you what machine instructions are, how the fetch-execute cycle works, and how memory is used to enable the machine to do its job. You will learn the operation and mechanisms of the bare-bones computer and demystify a lot of computer talk that you could not otherwise ever understand.

But how can we type Java or other languages into our computer and expect them to work? The previous chapter taught us that the machine can only understand machine instructions, and we do not wish to use these primitive kinds of commands. Our solution is to build a translator that will translate the language that we prefer into a form that the machine can process. This chapter shows you a very powerful translation technology that can translate computer languages or portions of natural languages into a form that a computer can execute. You will learn in this chapter what people mean when they say they "compiled" a program and you will do some compiling yourself.

The "operating system" for a computer is the program that interfaces with you and enables you to access the many functions of the machine. The operating system may provide you with menus, a command line, a spoken language or direct manipulation capability, or many other kinds of input schemes. It also enables you to use those schemes to access the editor, a mail facility, a web browser, a programming environment, a file manager, and many other subsystems. The operating system thus provides the bridge between you and the many services offered by the machine. This chapter describes operating systems, what they are, and how they work.

While computers and networking are becoming important in our lives, they also can become vehicles of mischief. What if our personal secrets and/or our money are stolen via the Web? What if we become dependent on machines and suddenly they cease to work because of an electronic attack? We must have defenses against those who would misuse machines or who would undo our well-being via electronic means. This chapter explains many of the kinds of attacks that might be brought against you or your various organizations. And it explains some of the defenses that you can use including a well designed password system and various encryption methods.