fundamentals of java text by: lambert and osborne

Fundamentals of

JavaText by: Lambert and Osborne

Unit 1 Getting Started with

JavaLesson 1:

Background

Lesson 1: Background

Objectives:Give a brief history of computers.Describe how hardware and software make up

computer architecture.Understand the binary representation of data and

programs in computers.Discuss the evolution of programming languages.Describe the software development process.Discuss the fundamental concepts of object-

oriented programming.

Lesson 1: BackgroundVocabulary:

o Application softwareo Assembly languageo Auxiliary input/output deviceso Auxiliary storage deviceso Bito Byteo Central processing unit (CPU)o Hardwareo Information hidingo Instance variableso Internal memoryo Machine language

Lesson 1: BackgroundVocabulary (continued):

o Network connectiono Object-oriented programmingo Primary memoryo RAMo ROMo Secondary memoryo Softwareo Software development life cycle

(SDLC)o System softwareo Ubiquitous computingo User interfaceo Waterfall model

1.1 History of Computers

• 1940s: The ENIAC was one of the world’s first computers.Large stand-alone machineUsed large amounts of electricityContained miles of wires and thousands of vacuum

tubesConsidered immensely useful when compared to

hand-operated calculators


• 1950s: IBM sold its first business computer.Computational power was equivalent to 1/800 of a

typical 800-megahertz Pentium computer sold in 2000

1/2000 of the computing power of today’s laptopsPerformed one task at a timeTypical input and output devices were punch cards

and paper tape


• 1960s: Expensive time-sharing computers became popular in large organizations that could afford them.30 people could work on one computer

simultaneouslyInput occurs via teletype machineOutput is printed on a roll of paperCould be connected to the telephone


• 1970s: The advantages of computer networks was realized.Email and file transfers were born

• 1980s: PCs became available in large numbers.Networks of interconnected PCs became popular

(LANs)Organizations utilized resource and file sharing


• 1990s: An explosion of computer use occurs.Hundreds of millions of computers are being used

in businesses and homesMost computers are now connected to the InternetJava is quickly becoming the common language of

today’s computersComputing has become ubiquitous.– Cell phones, cameras, PDAs, music player

1.2 Computer Hardwareand Software

Computers consist of two primary components:

1. HardwarePhysical devices that you see on your desktop

2. SoftwarePrograms that give hardware useful functionality


• Hardware– A bit (or binary digit)

• The smallest unit of information processed by a computer

• Consists of a single 0 or 1

– Bytes• Consists of 8 adjacent bits

• The capacity of computer memory and storage devices is usually expressed in bytes


Hardware– As illustrated in figure 1-2, a PC consists of six major

subsystems1. User interface

2. Auxiliary I/O devices - keyboard, monitor, printer, etc.

3. Auxiliary storage devices - flash memory, DVDs, etc.

4. Network connection - Modem, Ethernet cards

5. Internal memory

– RAM - random access memory

– ROM - read only memory

6. Central processing unit - Performs basic tasks of the computer

– Moore’s Law: Speed doubles every 2 years

–Transistors are the building blocks of CPU and RAM


Software• Computer software processes complex

patterns of 0s and 1s and transforms them to be viewed as text, images, etc.

1.2 Computer Hardware and Software

Two broad categories of software:1. System Software:

• supports the basic operations of a computer

• allows users to transfer information to and from the computer• Examples: OS, Compilers, Communications Software, User

Interface Subsystem

2. Application Software:• allows users to accomplish specialized tasks

• Examples: Word Processors, Spreadsheets, Database systems, Other programs we write

1.2 Computer Hardware and Software

Commonly used terms to describe storage

1.3 Binary Representation of Information and Computer Memory

Examine how different types of information are represented in binary notation.

Integers Floating Point Numbers Characters and Strings Images Sound Program Instructions Computer Memory


Computer memory stores patterns of electronic signals.

The patterns are strings of binary digits or bits. Computers use binary (base 2) notation. Two bases: On/Off Computer scientists also use bases octal (8) and hexadecimal (16).


• Example: Analyze the meaning of 100112, where the subscript 2 indicates that base 2 is being used


• Table 1-1 shows some base 10 numbers and their base 2 equivalents.


• Table 1-2 displays some characters and their corresponding ASCII bit patterns.


• Java uses Unicode

Patterns of 15 bits from

0000 0000 0000 0000 to

1111 1111 1111 1111


Sound is analog data. Analog information has a continuous range of infinite

values. Sampling reads the waveform at intervals. Memory requirements for sound are higher than text.

✓ Images Sampling measures color values as pixels in a two-

dimensional grid. Grayscale, black-and-white, RGB, true-color


Video Video includes a soundtrack and a set of images

called frames. Data compression is difficult.

✓Program instructions A sequence of bits in RAM

✓Computer Memory A gigantic sequence of bytes, each with an

address.


• Java uses Unicode

Patterns of 15 bits from

0000 0000 0000 0000 to

1111 1111 1111 1111

1.4 Programming Languages

• Generation 1 – Late 1940s to Early 1950s: Machine Languages

Programmers entered programs and data directly into RAM using 1s and 0s

Several disadvantages existed: Coding was error prone, tedious, and slow Modifying programs was extremely difficult It was nearly impossible for a person to decipher

someone else’s program Programs were not portable Each type had its own machine language

1.4 Programming Languages Generation 2 – Early 1950s to Present:

Assembly Languages Uses mnemonic symbols to represent instructions

and data Assembly language is:

More programmer friendly than machine language Tedious to use and difficult to modify Since each type of computer has its own unique

assembly language, it is not portable Programs are translated by assembler and loaded and

run using a loader. Assembly language is more programmer friendly, but

still tedious.

1.4 Programming Languages Generation 3 – Mid-1950s to Present: High-

Level Languages Designed to be human friendly – easy to read, write,

and understand Each instruction corresponds to many instructions in

machine language Translation to machine language occurs through a

program called a ‘compiler’ Examples: FORTRAN, COBOL, BASIC, C, Pascal,

C++, Smalltalk, Python, and Java Java does not need to be recompiled for each type of

computer.

1.5 The Software Development Process

Creating high-quality software involves organization, planning and utilizing various diagrammatic conventions

Computer scientists have created a view of the software development process known as the ‘software development life cycle’ (SDLC)

One method is known as the ‘waterfall model’’ A mistake made in one phase often requires the

developer to back up and redo some of the work in the previous phase


The Waterfall Model consists of several phases: Customer Request Analysis Design Implementation Integration Maintenance

Figure 1-6. The waterfall model of the software development life cycle.


Mistakes found early in the SDLC are much less expensive to correct than those found late.


The cost of developing software is not spread equally over the phases. The percentages shown in Figure 1-6 are typical.


1.6 Basic Concepts of Object-Oriented Programming

High-level programming languages utilize two different approaches

Procedural approach Examples: COBOL, FORTRAN, BASIC, C and Pascal

Object-oriented approach - Superior approach Examples: Smalltalk, C++, Python, and Java


Object-oriented programming (OOP) involves: Planning

Determine your needs Create a list of necessary resources Establish the rule of behavior to be followed

Execution Outcome Classes define:

✓ Instance variables (data resources)✓ Methods (rules of behavior)✓ Combining resources and behaviors into a single

software entity is encapsulation


Classes are organized into hierarchies. Subclasses share methods and instance variables with

the root class using inheritance. Different types of objects can understand the same

message, called polymorphism. An object’s response to a message depends on its class.


The Expedition analogy to OOP


In this chapter, you learned:The modern computer age began in the late 1940s with the development of ENIAC. Business computing became practical in the 1950s, and time-sharing computers advanced computing in large organizations in the 1960s and 1970s. The 1980s saw the development and first widespread sales of personal computers, and the 1990s saw personal computers connected in networks. During the first decade of the twenty-first century, computing has become ubiquitous.


✓Modern computers consist of two primary components: hardware and software. Computer hardware is the physical component of the system. Computer software consists of programs that enable us to use the hardware.

✓All information used by a computer is represented in binary form. This information includes numbers, text, images, sound, and program instructions.


✓Programming languages have been developed over the course of three generations: generation 1 is machine language, generation 2 is assembly language, and generation 3 is high-level language.

✓The waterfall model of the software development process consists of several standard phases: customer request, analysis, design, implementation, integration, and maintenance


✓Object-oriented programming is a style of programming that can lead to better-quality software. Breaking code into easily handled components simplifies the job of writing a large program.

THE THE ENDEND

fundamentals of java text by: lambert and osborne

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