41

44

C H A P T E R

Software: Software: Systems and Systems and Application Application

SoftwareSoftware

42

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

Software vs. Hardware Costs

43

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.

44

Spheres of Influence and Software

Sphere of influenceThe scope of the problems and opportunities addressed by a particular organization.

Personal

Workgroup

Enterprise

Information systems that serve the needs of an individual user.

Two or more people who work together to achieve a common goal.

Information systems that support the firm in its interaction with its environment

45

Spheres of Influence and Software

Personal

Workgroup

Enterprise

Word processing, spreadsheets, databases, e-mail

Order entry, billing, applications

Systems that support information sharing, group scheduling, group decision making, and conferencing

Examples of software

46

Classifying Software by Type and Sphere of Influence (Table

4.1)

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Software Issues and Trends

• 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.

49

Operating System Functions

Operating System Functions

Perform common computer hardware functionsProvide a user interfaceProvide a degree of hardware independenceManage system memoryManage processing tasksProvide networking capabilityControl access to system resourcesManage files

410

User Interface

• 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.

OS

Hardware

Application

OS

Hardware

Application

OS

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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 (Figure 4.4)

• 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.

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Software Concepts

• 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

• 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.

Examples of Utility Programs

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Types of Application Software

• 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