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    Chapter 5Information Systems

    in Business: Software

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    Learning Objectives

    When you finish this chapter, you will:

    Understand why managers must keep abreast

    of software developments. Recognize the different generations of

    programming languages and how they differ.

    Understand the difference between

    application software and system software.

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    Learning Objectives

    Know the strengths and weaknesses of

    tailored software vs. off-the-shelf software.

    Be able to cite the latest major

    developments in application and system

    software.

    Recognize characteristics that are important

    in evaluating packaged software applicationfor business use.

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    Software: Instructions

    to the Computer

    A computer program is a series of instructions

    to a computer to execute any and allprocesses.

    Computers only understand instructions

    consisting of electrical signals alternatingbetween two states.

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    Programming Languages

    Programming languages

    Abbreviated forms of instructions that

    translate into machine language

    New programming languages make

    programming easier for people who are not

    necessarily hardware experts

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    Programming Languages

    Figure 5.1

    The evolution of

    programming

    languages

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    Programming Languages

    Machine Languages (ML)

    Only languages computers can directly

    interpret to carry out instructions String of 0s and 1s for a machine language

    instruction

    ML coding: time-consuming and error-prone

    ML programmers: concerned with hardware

    details

    Every computer or family of computers has its

    own ML; each is machine-dependent.

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    Programming Languages

    Assembly Languages More English-like; codes shorter than

    machine languages

    Assembler translates into machine language

    Advantages of machine or assembly

    languages

    Programmer in control of hardware Programs written in low-level languages run more

    efficiently.

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    Programming Languages

    Figure 5.2 The instruction ADD 2 and 5 and assign the result to variable

    y written in different programming languages

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    Programming Languages

    Procedural Languages Third-generation (procedural) languages are

    more English-like than assembly languages.

    Programmers focus on the procedure of the

    application problem at hand.

    Some languages are standardized or

    portable. Relatively easy to learn, write, and debug.

    FORTRAN, COBOL, BASIC

    Requires compiling and linking to test

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    Programming Languages

    Fourth Generation Languages (4GL) 4GLs are more English-like than procedural

    languages.

    Programmer only has to select an action

    without having to specify the actions formula

    or procedure.

    Easy to learn and use; shorter applicationdevelopment time.

    PowerBuilder, FOCUS, NOMAD, and RAMIS

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    Programming Languages

    Visual Programming Languages that let programmers create field

    windows, scroll-down menus, click buttons,

    etc., by choosing from a paletteAppropriate code written automatically

    Integrated programming environment

    Accelerates work Microsofts Visual Basic

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    Programming Languages

    Object-Oriented Programming (OOP)

    Emphasis on the objects involved in the task,

    not on the procedure.An object encapsulates a data set with the

    code that is used to operate on it.

    Standardized programming modules can be

    reused.

    Applications can be rapidly developed with

    appropriate objects from an object library.

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    Programming Languages

    Figure 5.3 Advantages of object-oriented programming (OOP) over procedural

    languages

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    Programming Languages

    Figure 5.4 The object EMPLOYEE

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    Programming Languages

    Figure 5.5 Advantages and disadvantages of higher-level

    programming languages

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    Programming Languages

    Application Software vs. System

    Software

    Application: a program developed to

    address a specific business need;software for development of such

    programs.

    System: programs designed to carry out

    general routine operations, such as

    loading, copying, or deleting a file.

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    Application Software

    Application-specific programs Programs designed to perform specific jobs

    General-purpose programs

    Usable for different purposes

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    Application Software

    Custom-Designed Applications

    Advantages:

    Meeting the organizations needs exactly In-house developers are sensitive to the

    organizational culture

    Disadvantages:

    High cost

    Production schedule subject to long delays

    Incompatible with other organizations

    systems

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    Application Software

    Figure 5.6 Advantages and disadvantages of custom applications

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    Application Software

    Packaged Software

    Advantages:

    Low cost High quality

    Vendor support

    Immediate availability

    Often tested at user sites (alpha sites

    and beta sites) before the final version is

    released.

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    Application Software

    Figure 5.7 Advantages and disadvantages of packaged software

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    Applications Software

    Packaged General Purpose Software

    Word processors

    Electronic spreadsheets Database management systems

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    Packaged Software

    Figure 5.8 Electronicspreadsheets are powerful

    tools for (a) tabulation, (b)

    manipulation, and (c) data

    analysis.

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    Packaged Software

    Multimedia

    Can handle many different types of data

    such as text, voice, and image. Powerful means of communicating.

    Uses include education, training,

    research, and business.

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    Packaged Software

    Virtual Reality (VR) Mimics sensory reality.

    Some sophisticated VR software includes use

    of goggles, gloves, earphones, and a moving

    base.

    Business use of VR is expected to grow

    dramatically for design and testing of newproducts, and for marketing.

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    System Software

    Manages computer resources and

    performs routine tasks not specific to

    any application

    Copying and pasting sections and files

    Printing documents

    Controlling hardware functions

    Allocating memory

    Developed to partner with application

    software

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    System Software

    Operating Systems (O/S)

    Most important system software

    Developed for a certain microprocessor ormicroprocessors

    Addresses technical details such as

    registers and RAM addresses.

    Plays the role of traffic cop or the bossof computer resources.

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    System Software

    Figure 5.9 The operating system mediates between applications and the

    computer, and controls peripheral devices.

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    System Software

    Figure 5.10 Computers operate on a number of layers, starting from

    the user interface and moving inward to the hardware.

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    System Software

    Figure 5.11 Popular operating systems

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    System Software

    Operating System Functions Systems Management

    User Interface

    Memory Allocation Multitasking, Multiprogramming, and

    Multiprocessing

    Times and Statistics

    Increasing Services from O/Ss

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    System Software

    Compilers and Interpreters

    Compiler Scans source code and translates into object code

    Generates error message and does not compile

    when an error is found

    Allows users to save programs in object code

    Interpreter Checks one statement at a times

    Converts into object code and executes

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    System Software

    Figure 5.12 A compiler converts higher-level language code (source