Chapter 1 – Introduction to Computers, the Internet, and the WebSlide 21.1 Introduction1.2 What Is a Computer?1.3 Computer Organization1.4 Evolution of Operating Systems1.5 Personal, Distributed and Client/Server Computing1.6 Machine Languages, Assembly Languages and High-Level Languages1.7 History of C++1.8 History of Java1.9 Java Class Libraries1.10 FORTRAN, COBOL, Pascal and Ada1.11 BASIC, Visual Basic, Visual C++, C# and .NET1.12 The Internet and the World Wide Web1.13 Basics of a Typical Java EnvironmentFig. 1.1 Typical Java environment.1.14 General Notes about Java and This Book1.15 Thinking About Objects: Introduction to Object Technology and the Unified Modeling Language1.15 Thinking About Objects (cont.)Slide 20Slide 21Slide 22Slide 231.16 Discovering Design Patterns: Introduction1.16 Discovering Design Patterns (cont.)Slide 26 2003 Prentice Hall, Inc. All rights reserved.Chapter 1 – Introduction to Computers, the Internet, and the WebOutline1.1 Introduction1.2 What Is a Computer?1.3 Computer Organization1.4 Evolution of Operating Systems1.5 Personal, Distributed and Client/Server Computing1.6 Machine Languages, Assembly Languages and High-Level Languages1.7 History of C++1.8 History of Java1.9 Java Class Libraries1.10 FORTRAN, COBOL, Pascal and Ada 1.11 BASIC, Visual Basic, Visual C++, C# and .NET 1.12 The Internet and the World Wide Web1.13 Basics of a Typical Java Environment 2003 Prentice Hall, Inc. All rights reserved.Chapter 1 – Introduction to Computers, the Internet, and the Web1.14 General Notes about Java and This Book1.15 Thinking About Objects: Introduction to Object Technology and the Unified Modeling Language1.16 Discovering Design Patterns: Introduction 2003 Prentice Hall, Inc. All rights reserved.1.1 Introduction•Java How to Program, Fifth Edition–Java 2 Standard Edition–Object-oriented programming 2003 Prentice Hall, Inc. All rights reserved.1.2 What Is a Computer?•Computer–Performs computations and makes logical decisions–Millions / billions times faster than human beings•Computer programs–Sets of instructions for which computer processes data•Hardware–Physical devices of computer system•Software–Programs that run on computers 2003 Prentice Hall, Inc. All rights reserved.1.3 Computer Organization•Six logical units of computer system–Input unit•Mouse, keyboard–Output unit•Printer, monitor, audio speakers–Memory unit•Retains input and processed information–Arithmetic and logic unit (ALU)•Performs calculations–Central processing unit (CPU)•Supervises operation of other devices–Secondary storage unit•Hard drives, floppy drives 2003 Prentice Hall, Inc. All rights reserved.1.4 Evolution of Operating Systems•Batch processing–One job (task) at a time–Operating systems developed•Programs to make computers more convenient to use•Switch jobs easier•Multiprogramming–“Simultaneous” jobs–Timesharing operating systems 2003 Prentice Hall, Inc. All rights reserved.1.5 Personal, Distributed and Client/Server Computing•Personal computing–Computers for personal use•Distributed computing–Computing performed among several computers•Client/server computing–Servers offer common store of programs and data–Clients access programs and data from server 2003 Prentice Hall, Inc. All rights reserved.1.6 Machine Languages, Assembly Languages and High-Level Languages•Machine language–“Natural language” of computer component–Machine dependent•Assembly language–English-like abbreviations represent computer operations–Translator programs convert to machine language•High-level language–Allows for writing more “English-like” instructions•Contains commonly used mathematical operations–Compiler convert to machine language•Interpreter–Execute high-level language programs without compilation 2003 Prentice Hall, Inc. All rights reserved.1.7 History of C++•C++–Evolved from C•Evolved from BCPL and B–Provides object-oriented programming capabilities•Objects–Reusable software components that model real-world items 2003 Prentice Hall, Inc. All rights reserved.1.8 History of Java•Java–Originally for intelligent consumer-electronic devices–Then used for creating Web pages with dynamic content–Now also used for:•Develop large-scale enterprise applications•Enhance WWW server functionality•Provide applications for consumer devices (cell phones, etc.) 2003 Prentice Hall, Inc. All rights reserved.1.9 Java Class Libraries•Classes–Include methods that perform tasks•Return information after task completion–Used to build Java programs•Java contains class libraries–Known as Java APIs (Application Programming Interfaces) 2003 Prentice Hall, Inc. All rights reserved.1.10 FORTRAN, COBOL, Pascal and Ada•Fortran–FORmula TRANslator•COBOL–COmmon Business Oriented Language•Pascal–Structured programming•Ada–Multitasking 2003 Prentice Hall, Inc. All rights reserved.1.11 BASIC, Visual Basic, Visual C++, C# and .NET•BASIC–Beginner’s All-Purpose Symbolic Instruction Code•Visual Basic .NET–Framework Class Library (FLC)•Visual C++–Microsoft Foundation Classes (MFC)•C#–C-Sharp•.NET–.NET platform 2003 Prentice Hall, Inc. All rights reserved.1.12 The Internet and the World Wide Web•Internet–Developed more than four decades ago with DOD funding–Originally for connecting few main computer systems–Now accessible by hundreds of millions of computers•World Wide Web (WWW)–Allows for locating/viewing multimedia-based documents 2003 Prentice Hall, Inc. All rights reserved.1.13 Basics of a Typical Java Environment•Java programs normally undergo five phases–Edit•Programmer writes program (and stores program on disk)–Compile•Compiler creates bytecodes from program–Load•Class loader stores bytecodes in memory–Verify•Verifier ensures bytecodes do not violate security requirements–Execute•Interpreter translates bytecodes into machine language 2003 Prentice Hall, Inc. All rights reserved.Fig. 1.1 Typical Java environment.PrimaryMemory......DiskDiskDiskEditorCompilerClass LoaderProgram is created in an editor and stored on disk in a file ending with .java.Compiler creates bytecodes and stores them on disk in a file ending with .class.Class loader reads .class files containing bytecodes from disk