• Laying the Groundwork

  • 1 The Big Picture

• The Information Layer

  • 2 Binary Values and Number Systems

  • 3 Data Representation

• The Hardware Layer

  • 4 Gates and Circuits

  • 5 Computing Components

• The Programming Layer

  • 6 Low-Level Programming Languages and Pseudocode

  • 7 Problem Solving and Algorithms

  • 8 Abstract Data Types and Subprograms

  • 9 Object-Oriented Design and High-Level Programming Languages

• The Operating Systems Layer

  • 10 Operating Systems

  • 11 File Systems and Directories

• The Applications Layer

  • 12 Information Systems

  • 13 Artificial Intelligence

  • 14 Simulation, Graphics, Gaming, and Other Applications

• The Communications Layer

  • 15 Networks

  • 16 The World Wide Web

  • 17 Computer Security

• In Conclusion

  • 18 Limitations of Computing

In the programming layer, we have moved from the concreteness of machine language, to assembly language, to pseudocode, to expressing algorithms. We then went from algorithms using simple variables to algorithms using arrays.

Now we take a step up in abstraction and talk about abstract containers: composite structures for which we do not know the implementation. In computing circles, these abstract containers are called abstract data types. We know their properties and operations and we understand which types of values they can contain, but we have no information about their internal structure or implementation. That is, we know what the operations are and what they do, but we do not know how the operations are implemented.

The algorithm design we have been using is a top-down model, in which we break a task into smaller pieces. We conclude this chapter with more about subprogram statements, which are both a way to make the code mirror the design and the way that algorithms and subalgorithms communicate.