Software: Systems and Application Software

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Software Systems and Application Software

• Chapter 4

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Learning Objectives

• Identify describe the functions of the 2 basic
  kinds of software.
• Outline the role of the operating system
  identify the features of several popular
  operating systems.

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Learning Objectives

• Discuss how applications software can support
  personal, workgroup and enterprise business
  objectives.
• Identify 3 basic approaches to developing
  applications software and discuss the pros and
  cons of each.

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Learning Objectives

• Outline the evolution of programming languages
• Differentiate among the five generations of
  programming languages

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Software Overview

• Computer program sequences of instructions for
  the computer.
• Documentation describes program functions to help
  people use it
• Systems software coordinates the activities of
  hardware programs.
• Applications software helps users solve
  particular problems.

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Supporting Individual, Group, and Organizational
Goals

• Table 4.1

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Systems Software

• Operating systems
• Utility programs

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Operating Systems
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Operating Systems

• Fig. 4.2

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Operating Systems Activities

• Perform common hardware functions
• Provide a user interface
• Provide hardware independence

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Operating Systems Activities

• Manage system memory
• Manage processing
• Control access to system resources
• Manage files

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Perform common hardware functions

• Accept keyboard input
• Store data on disks
• Send data to output devices

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Provide a user interface

• Command-based interfaces
• Graphical User Interfaces (GUIs)

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Provide hardware independence

• Figure 4.3

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Memory Management

• Fig 4.4

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Manage processing

• Multitasking more than one program can run at a
  time using a single processor
• Time sharing multiple users simultaneously using
  the resources of a single processor
• Scalability easy adaptation to more users or
  tasks

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Manage files

• Physical storage location
• File permissions
• File access

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Control access to system resources

• Protection against unauthorized access
• Logins and passwords

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Operating System Examples

• Table 4.2

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Workgroup Operating Systems

• Netware
• Windows NT Server 4.0
• Windows 2000 Server

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Enterprise Operating Systems

• IBMs OS/390
• HPs MPE/iX (Multiprogramming Executive with
  integrated POSIX)

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Consumer Appliance Operating Systems

• Windows CE
• Mobil Linux

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Utility Programs
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Table 4.3
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Types and Functions of Applications Software
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Personal Application Software
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Object Linking Embedding (OLE)

• Fig 4.16

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Workgroup Application Software

• Groupware
• Collaborative computing software

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Table 4.6
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Enterprise Application Software

• Table 4.7

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Figure 4.17
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Enterprise Resource Planning (ERP)

• ERP software a set of integrated programs that
  manage a companys critical business operations
• ERP software can support global operations so
  it must support many languages, legal entities,
  and currencies

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Table 4.8
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Benefits of ERP Systems

• Eliminate inefficient systems
• Improved data access for decision making
• Facilitate the adoption of improved work
  processes
• Supply chain management

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The Downside of of ERP Systems

• Costly
• Changed business processes
• Employee resistance

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Programming Languages

• Commands and statements combined according to a
  particular syntax
• Different languages have different characteristics

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Table 4.9
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First-Generation Languages
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Second-Generation Languages

• Assembly languages
• Assemblers
• Symbolic language

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Third-Generation Languages

• Greater use of symbolic code
• Statements are more English-like
• Easier to learn
• Resulting program slower dont use RAM as
  efficiently
• Examples BASIC, COBOL, C, C, FORTRAN

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Fourth-Generation Languages

• 4GLs
• Programs tell the CPU the desired results, not
  how to get them
• Examples SQL, Visual Basic, SAS

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Object-Oriented Programming Languages

• Objects include data actions. Objects interact
  by passing messages
• Encapsulation group items into an object
• Polymorphism One procedure can work with
  multiple objects.
• Inheritance an object in a particular class gets
  attributes of that class.

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Fig 4.19
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Selecting a Programming Language

• Trade offs of language characteristics, cost,
  control complexity
• Assembly language programs are fast efficient
  offer the programmer control over the hardware
• Third- and fourth- generation languages are
  easier to learn use

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Language Translators
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Fig 4.20 interpreter
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Fig 4.21 compiler
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Software Issues Trends

• Software bugs program defects that prevent
  proper performance
• Open source software freely available and
  modifiable
• Software licensing
• Software upgrades
• Global software support