Transcript C H A P T E R

CHAPTER
4
Software:
Systems and
Application
Software
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Software and Hardware
(Figure 4.1)
• Software is a critical piece of
making computers perform.
• Computer Programs
 Sequences of instructions
for the computer
• Classes of software
 Systems Software
 Application Software
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Software vs.
Hardware Costs
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Software Classes
• Systems Software
 Set of programs that coordinates
activities and functions of the hardware
and various other programs.
• Application Software
 Programs that help users solve particular
computing problems.
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Spheres of Influence and
Software
Sphere of influence
The scope of the problems
and opportunities addressed
by a particular organization.
Two or more people who work
together to achieve a common goal.
Workgroup
Personal
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Information
systems that
serve the needs
of an individual
user.
Enterprise
Information systems
that support the
firm in its
interaction with its
environment
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Spheres of Influence and
Software
Systems that support information sharing, group
scheduling, group decision making, and conferencing
Workgroup
Examples of software
Personal
Word processing,
spreadsheets,
databases, e-mail
Enterprise
Order entry, billing,
applications
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Classifying Software by Type and
Sphere of Influence (Table 4.1)
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Software Issues and Trends
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• Software Licensing
 Protection by software vendors to prevent
unauthorized use.
• Software Upgrades
 A revised version of software that usually
includes fixes of known problems, plus
enhancements to existing capabilities.
• Global Software Support
 Software that is distributed around the globe
may require unique support mechanisms due to
local political and economic conditions.
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Role of Systems Software
(Figure 4.2)
• Role of System Software
 An interface or buffer
between application software
and hardware.
• Operating Systems
 Control the computer hardware
and act as an interface with
applications programs.
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Operating System Functions
Operating System Functions
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Perform common computer hardware functions
Provide a user interface
Provide a degree of hardware independence
Manage system memory
Manage processing tasks
Provide networking capability
Control access to system resources
Manage files
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User Interface
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• User Interface
 A function of the operating system that allows
individuals to access and command the computer.
• Command-Based User Interface
 A particular user interface that requires text commands
be given to the computer to perform basic activities.
• Graphical User Interface (GUI)
 A user interface that uses pictures (icons) and menus
displayed on the screen to send commands to the
computer system.
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Advantages of Using a Graphical
User Interface (Table 4.2)
Table 4.2
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Systems Software Concepts
• Hardware Independence
 Operating systems (OSs)
provide hardware independence
for application software. The
application software interfaces
with the operating system which
interfaces with the hardware.
When the hardware is changed,
the operating system is changed
so that the application software
is not required to be changed.
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Application
Application
OS
OS
OS
Hardware
Hardware
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Software Concepts
(Figure 4.3)
• Memory Management
 Controls how memory is accessed and maximizes
available memory and storage.
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Software Concepts
• Virtual Memory
 Memory that allocates
space in secondary storage
to supplement the
immediate, functional
memory capacity of RAM.
• Paging
 A function of virtual
memory that allows the
computer to store currently
needed pages in RAM
while the rest of these
programs wait in secondary
storage.
(Figure 4.4)
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Software Concepts
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• Multitasking
 A processing activity that allows a user to run
more than one application at the same time.
• Multithreading
 A processing activity that is basically
multitasking within a single application.
• Time-sharing
 A processing activity that allows more than one
person to use a computer system at the same
time.
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Software Concepts
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• Network capability
 Aids in connecting the computer to a network.
• Access to system resources
 Provides security for unauthorized access.
• File management
 Ensures that files in secondary storage are
available when needed, and they are protected
against unauthorized usage.
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Popular Operating Systems
(Table 4.3)
(Table 4.3)
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Utility Programs
(Table 4.4)
• Utility Programs
 Programs used to merge and sort sets of data, keep
track of computer jobs being run, compress files of
data before they are stored or transmitted over a
network, and perform other important tasks.
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Examples of Utility Programs
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Types of Application Software
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• Proprietary Software
 Designed to solve a unique and specific
problem.
 In-House Developed
 Development of application software using
the company’s resources.
 Contract Software
 Developed for a particular company.
• Off-The-Shelf Software
 An existing software program that can be used
without considerable changes expected.
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Sources of Software
• Customized Package
 Blend of external and internal software
development.
In-House Customized
 Contract Customization

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