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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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Figure 5.1

The evolution of

programming

languages


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

languages


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Figure 5.4 The object EMPLOYEE


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Figure 5.5 Advantages and disadvantages of higher-level

programming languages


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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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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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Figure 5.6 Advantages and disadvantages of custom applications


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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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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

code) into machine language (object code), which the computer can

process.


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System Software

Data Communication Programs

Controls and supports data

communication activities in a network Setting up rules that govern transmission and

reception of data

Connecting and disconnecting communication

links

Assigning priorities among terminals in a network

Detecting and correcting transmission errors


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System Software

Proprietary vs. Open Source Proprietary O/S: limited to using applications

compatible with it

Open O/S: compatible with virtually allapplications.

Completely open O/S does not exist

Some O/Ss (e.g., Unix) are said to benonproprietary, but it is still impossible to run

many applications on different versions of such

O/Ss.


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Considerations in Purchasing

SoftwareFigure 5.13 Sample software

evaluation form


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Considerations in Purchasing

Software

Figure 5.14 Sample results of software evaluation (5 is the highest score.)