1.3 Computing as a Tool and a Discipline
In the previous section on the history of computer software, we highlighted the ever-changing role of the user. At the end of the first generation, users were split into two groups: systems programmers, who developed tools to make programming easier, and applications programmers, who used those tools. Later, applications programmers built large domain-specific programs such as statistical packages, word processors, spreadsheets, intelligent browsers, virtual environments, and medical diagnosis applications on top of the traditional language tools. These application programs were, in turn, used by practitioners with no computer background.
So who is using the computer as a tool? Everyone, except for those people who are creating the tools for others. For these toolmakers, either computing is a discipline (low-level tools) or the discipline of computing has made their tools possible (applications built upon applications).
A discipline is defined as a field of study. Peter Denning defines the discipline of computer science as “the body of knowledge and practices used by computing professionals in their work. . . . This discipline is also called computer science and engineering, computing, and informatics.”19 He continues, “The body of knowledge of computing is frequently described as the systematic study of algorithmic processes that describe and transform information: their theory, analysis, design, efficiency, implementation, and application. The fundamental question underlying all of computing is, What can be (efficiently) automated?”
Denning states that each practitioner must be skilled in four areas:
Algorithmic thinking, in which one is able to express problems in terms of step-by-step procedures to solve them
Representation, in which one is able to store data in a way that it can be processed efficiently
Programming, in which one is able to combine algorithmic thinking and representation into computer software
Design, in which the software serves a useful purpose
A debate has long raged about whether computing is a mathematical discipline, a scientific discipline, or an engineering discipline. The reality is that it has aspects of all three. Computing certainly has strong roots in mathematical logic. The theorems of Turing tell us that certain problems cannot be solved, Boolean algebra describes computer circuits, and numerical analysis plays an important role in scientific computing. Scientific disciplines apply a rigorous, analytical process for testing hypotheses. The natural sciences (such as biology, physics, and chemistry) exist to “fill in the instruction book that God forgot to leave us.”20 But the scientific method can be applied to any organized investigation. Computer scientists test hypotheses related to various aspects of computing. When we design and build larger and more complex computing systems, we use techniques from engineering.
The Big Ideas of Computing
The AP Computer Science Principles curriculum lists seven big ideas that are essential to understanding computing.21 They are summarized in TABLE 1.1.
| TABLE | |
| 1.1 Big Ideas in Computing | |
| Creativity | Computing has changed the way humans can be creative, including the creation of video, animation, infographics, and audio. |
| Abstraction | Abstraction is the mechanism used to model the world and facilitate communication among humans and machines. |
| Data and information | Crucial to computing is the management and interpretation of data and information, leading to the creation of knowledge. |
| Algorithms | Algorithms allow us to develop and express solutions to problems. |
| Programming | Of course, computing involves programming, which allows us to implement the solutions to problems. |
| The Internet | Not only does the Internet provide a mechanism for communicating and sharing resources among people and machines, it also has become the means by which computing is accomplished in many situations. |
| Global impact | Computing enables innovation, which has potential benefits and harmful effects in various contexts. |
© Artur Debat/Getty Images; © Alan Dyer/Stocktrek Images/Getty Images
When you think about creativity, you might think about artists. You might not think of a computer as a device that promotes creativity, but it certainly is. The artifacts created using a computer are still the result of a human being’s ingenuity. Presentations, images, audio, video, web pages, and programs are all brought about by human acts of creation. We use software tools to do so, just as a sculptor uses a chisel, but the end product is created by the human’s efforts, not the tool.
Even the process of writing a program, often considered a core computing activity, is a creative effort. The purpose of a program depends on the goals of the programmer and the end user (the person who runs the program). A program might be created to satisfy personal curiosity to solve a world-changing problem, or it might be used to develop insight into data. Often, the results of running a program can have an effect on a large number of people, and change organizations and even entire societies.
Despite its old-fashioned roots, the process of programming, and the resulting product, does not have to be a stale, boring thing, made only for crunching numbers. Programs may use various forms of input and output, including visual (text, graphics), audible (sound effects, music, human speech), or tactile (touch screens, vibrating controllers, and virtual reality gloves).
The process of creation using a computer involves a variety of techniques and tools, many of which we discuss throughout this text. Some you’ll be familiar with; others will likely be new to you. Many involve applying old ideas in new ways.
In this text we explore, at an introductory level, all of these big ideas to varying degrees. This text does not aim to make you a better computer user, although it should undoubtedly have that side effect. Instead, we want you to walk away with a thorough knowledge of how computing systems work, where they are now, and where they may go in the future.
SUMMARY
This book is a broad study of computer systems, including the hardware that makes up the devices, the software programs executed by the machine, and the data managed and manipulated by both. Computing systems can be divided into layers, and our organization of this book follows those layers from the inside out.
The history of computing reveals the roots from which modern computing systems grew. This history spans four generations, each characterized by the components used to build the hardware and the software tools developed to allow the programmer to make more productive use of the hardware. These tools have formed layers of software around the hardware.
Throughout the rest of this book, we examine the different layers that make up a computing system, beginning with the information layer and ending with the communication layer. Our goal is to give you an appreciation and understanding of all aspects of computing systems.
You may go on to study computer science in depth and contribute to the future of computing systems. Or you may go on to be an application specialist within other disciplines, using the computer as a tool. Whatever your future holds, given how prevalent computing systems are, a fundamental understanding of how they work is imperative.
KEY TERMS
EXERCISES
For Exercises 1–10, choose from the following list of people.
Leibniz
Pascal
Babbage
Lovelace
Hollerith
Byron
Turing
Jacquard
For Exercises 11–23, match the hardware listed to the appropriate generation.
First
Second
Third
Fourth
Fifth
For Exercises 24–38, match the software or software concepts listed to the appropriate generation.
First
Second
Third
Fourth
Fifth
Exercises 39–59 are short-answer questions.
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48. Define the word abstraction and relate it to the drawing in Figure 1.2.
THOUGHT QUESTIONS
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3. Which big ideas in Table 1.1 do you think are the most important? Why?