Chapter 0: Introduction

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Chapter 0:

Introduction

Computer Science: An Overview Eleventh Edition

by

J. Glenn Brookshear

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Chapter 0: Introduction

• 0.1 The Role of Algorithms

• 0.2 The Origins of Computing Machines

• 0.3 The Science of Algorithms

• 0.4 Abstraction

• 0.5 An Outline of Our Study

• 0.6 Social Repercussions

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Terminology

• Algorithm: A set of steps that defines how a task is performed

• Program: A representation of an algorithm

• Programming: The process of developing a program

• Software: Programs and algorithms

• Hardware: Equipment

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Figure 0.1 An algorithm for a magic

trick

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History of Algorithms

• The study of algorithms was originally a subject in mathematics.

• Early examples of algorithms

– Long division algorithm – Euclidean Algorithm

• Gö del's Incompleteness Theorem: Some problems cannot be solved by algorithms.

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Figure 0.2 The Euclidean algorithm

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Origins of Computing Machines

• Early computing devices

– Abacus: positions of beads represent numbers – Gear-based machines (1600s-1800s)

• Positions of gears represent numbers

• Blaise Pascal, Wilhelm Leibniz, Charles Babbage

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Figure 0.3 An Abacus

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Early Data Storage

• Punched cards

– First used in Jacquard Loom (1801) to store patterns for weaving cloth

– Storage of programs in Babbage’s Analytical Engine

– Popular through the 1970’s

• Gear positions

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Early Computers

• Based on mechanical relays

– 1940: Stibitz at Bell Laboratories

– 1944: Mark I: Howard Aiken and IBM at Harvard

• Based on vacuum tubes

– 1937-1941: Atanasoff-Berry at Iowa State

– 1940s: Colossus: secret German code-breaker – 1940s: ENIAC: Mauchly & Eckert at U. of Penn.

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Figure 0.4 The Mark I computer

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Personal Computers

– First used by hobbyists

– IBM introduced the PC in 1981.

• Accepted by business

• Became the standard hardware design for most desktop computers

• Most PCs use software from Microsoft

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Into the Millennia

• Internet revolutionized communications

– World Wide Web

– Search Engines (Google, Yahoo, and Microsoft)

• Miniaturization of computing machines

– Embedded (GPS, in automobile engines) – Smartphone

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Computer Science

• The science of algorithms

• Draws from other subjects, including

– Mathematics – Engineering – Psychology

– Business Administration – Psychology

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Central Questions of Computer Science

• Which problems can be solved by algorithmic processes?

• How can algorithm discovery be made easier?

• How can techniques of representing and communicating algorithms be improved?

• How can characteristics of different

algorithms be analyzed and compared?

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Central Questions of Computer Science

(continued)

• How can algorithms be used to manipulate information?

• How can algorithms be applied to produce intelligent behavior?

• How does the application of algorithms affect society?

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Figure 0.5 The central role of

algorithms in computer science

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Abstraction

• Abstraction: The distinction between the external properties of an entity and the

details of the entity’s internal composition

• Abstract tool: A “component” that can be used without concern for the component’s internal properties

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Outline of Our Study

• Chapter 1: Data Storage

• Chapter 2: Data Manipulation

• Chapter 3: Operating Systems

• Chapter 4: Networks and the Internet

• Chapter 5: Algorithms

• Chapter 6: Programming Languages

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Outline of Our Study

(continued)

• Chapter 7: Software Engineering

• Chapter 8: Data Abstractions

• Chapter 9: Database Systems

• Chapter 10: Computer Graphics

• Chapter 11: Artificial Intelligence

• Chapter 12: Theory of Computation

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Social Repercussions

• Advances in computer science raise new questions.

– In law: Questions of rights and liabilities – In government: Questions of regulation – In the work place: Questions of

professionalism

– In society: Questions of social behavior

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Ethical Theories

• Consequence based:

What leads to the greatest benefit?

• Duty based:

What are my intrinsic obligations?

• Contract based:

What contracts must I honor?

• Character based:

Who do I want to be?