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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
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.)