Introduction to System Analysis and Design (Definition of System

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Introduction to System Analysis and
Design(Definition of System information system
components)
System Analysis and Design

• - Dr. Mahmoud Abu-Arra
• - Mr. Ahmad Al-Ghoul

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learning Objectives

• Describe the characteristics of system
• Define an information system and describe its
  components

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introduction

• Before talking about the characteristics of
  systems, and information system components let us
  have a historical view for the system analysis
  and design.
• The analysis and design of a computer based
  information systems began in the 1950s.
• Since then, the development environment has
  changed dramatically, driven by organizational
  needs as well as by rapid changes in the
  technological capabilities of computers
• In the 1950s, development focused on the
  processes the software performed
• Computer power was critical resource, efficiency
  of processing become the major goal
• Computer were large, expensive, and not very
  reliable
• All applications had to be developed in machine
  language or assembly language
• Software had to be developed from scratch,
  because there was no software industry

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introduction

• second step 1960s
• The second step begins with the first procedural,
  or third generation, computer programming
  languages in the beginning of 1960s
• Computers were still expensive and large but it
  gets more smaller and faster, less expensive than
  1950s
• With the third generation programming languages,
  software industry begins, but most organizations
  still developed their applications from scratch
  using their in-house development staff

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introduction

• Third step 1970s
• Organizations began to realize how expensive it
  was to develop customized information systems for
  every application
• early database management systems, using
  hierarchal and network models helped storage and
  retrieval of data
• The development of database management systems
  helped shift the focus of systems development
  from processes first to data first

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introduction

• Fourth step 1980s
• Microcomputers become key organizational tools
• The software industry expanded greatly as more
  and more people began to write off-the-shelf
  software for microcomputers
• Developers began to write more and more
  applications in fourth generation languages,
  which unlike procedural languages, instructed a
  computer on what to do instead of how to do it
• Computer-aided software engineering (CASE) tools
  were developed to make systems developers work
  easier
• A computer get smaller, faster, and cheaper
• The operating systems for computers moved away
  from line prompt interface to windows and icon
  based interfaces
• Organizations moved to applications with more
  graphics
• Organizations developed less software in-house
  and bought relatively more from software vendors
• System developers job went through a transition
  from builder to integrator

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introduction

• Fifth step 1990s
• Developers used visual programming environments,
  such as power builder or visual basic, to design
  the user interfaces for systems that run on
  client/server platforms
• Databases become relational or object oriented,
  and which may have been developed using software
  from firms such as Oracle, Microsoft. resided on
  the server
• Application logic resided on the same server with
  the database, alternatively, an organization may
  have decided to purchase its entire enterprise
  wide system
• More and more systems development efforts
  focused on the Internet, especially the web

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introduction

• Sixth step the new century
• The focus on developing systems for the Internet
  and for firms intranets and extranets
• Many CASE tools, such as those developed by
  Oracle, now directly support Web application
  development
• System implementation involves a three-tier
  design, with the database on one server, the
  application on a second server, and client logic
  located on user machines
• Moving to wireless system components, wireless
  devices, such as cell phones
• In some cases organizations not only do not
  develop the application in-house they dont even
  run the application in-house, choosing instead to
  use the application on a per-use basis by
  accessing in through an application service
  provider (ASP)

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Characteristics of Systems

• A system interrelated components working together
  for a common purpose
• Information system (IS)
• Arrangement of people, data, processes,
  information presentation and information
  technology that interact to support and improve
  day-to-day operations in a business as well as
  support the problem-solving and decision-making
  needs of management and users

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Characteristics of Systems

• Systems are made up of interrelated subsystems
  (e.g. a nuclear reactor is composed of boilers,
  reactor components etc.)
• Functional decomposition dividing a system into
  components based on subsystems (which are in turn
  further divided into subsystems)
• Functional Non-Functional components of a
  system
• System boundary the separation between a system
  and its environment (where inputs and outputs
  cross)
• Automation boundary separation between the
  automated part of system and the manual part

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Characteristics of Systems
The system boundary and the automation boundary
Environment Surrounding the System
System boundary
Manual Part of the System
Automated Part of the System
Automation boundary
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Characteristics of Systems
General Depiction of a System
input
boundary
interrelationship
subsystem
output
input
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Information System Components

• Information systems have five key components
  hardware, software, data, processes, and people

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Information System Components

• Hardware
• Is the physical layer of the information system
• Hardware includes work stations, servers,
  networks, telecommunication equipments, cables,
  input and output devices and many others.
• Hardware has become more powerful that give
  information systems more opportunities, and it
  also cut costs by becoming less expensive.

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Information System Components

• Software
• Software refers to the programs which control the
  hardware and produce the desired information and
  results
• Software consists of system software and
  application software
• System software manages the hardware components,
  which can include a single workstation or global
  network. Examples of system software include
• operating systems
• security software, that protects the computer
  from intrusion
• utility programs, that handle specific tasks such
  as data backup and disk management.
• Network operating system (NOS), which controls
  data, provide data security, manage network
  accounts.

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Information System Components

• Software
• Application software, the programs that support
  day-to day business functions and provide process
  and manage the information user need. Application
  software can serve one or any number of users.
  Examples of company-wide applications, called
  Enterprise applications, include order processing
  system, payroll systems, and company
  communication network
• Application software includes horizontal and
  vertical systems
• A horizontal system is a system, such as an
  inventory or payroll application, that can be
  adapted for use in many different types of
  companies
• A vertical systems is designed to meet the unique
  requirements of a specific business, such as a
  medical practice, or a video chain.

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Information System Components

• Data
• Is the raw material that an information system
  transforms into useful information
• Data can be stored in various locations, called
  tables
• The system can extract specific information by
  linking the tables
• Processes
• Define the tasks and business functions that
  users, managers, and IT staff members perform to
  achieve specific results
• Processes are the building blocks of an
  information system
• Processes represent actual day-to-day business
  operations

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Information System Components

• People
• those who operate the system those who provide
  its inputs and consume its outputs, and those who
  provide manual processing activities in a system,
  Users are the people who interact with an
  information system, both inside and outside the
  company
• We can divide users to two types internal and
  external
• Internal users include administrators, managers,
  technicians, sales staff, and corporate officers
• External users include customers who track their
  orders on the companys Web site and suppliers
  who use a customers system to plan their
  manufacturing schedules.

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Sequence Summary

• In this sequence, you learned about how systems
  analysis and design in organizations has changed
  over the past 40 years
• A system interrelated components working together
  for a common purpose
• Information system (IS) is arrangement of people,
  data, processes, information presentation and
  information technology that interact to support
  and improve day-to-day operations in a business
• Systems are made up of interrelated subsystems
  can be divided into sub systems depending on its
  functions
• The essential components of an information system
  are hardware, software, data, processes, and
  people

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Sequence Summary

• In this Sequence we have
• Described how systems analysis and design in
  organizations has changed over the past 40 years
• Defined the terms system and information system
• Described the characteristics of system
• Described information system components

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Reference

• 1 System Analysis and Design, Sixth Edition
• Authors Gary B. Shelly, Thomas J. Cashman and
  Harry J. Rosenblatt ,
• Publisher SHELLY CASHMAN SEWIES.
• 2 Modern Systems Analysis and Design Third
  Edition
• Authors Jeffrey A. Hoffer , Joey F. George,
  Joseph S. Valacich
• Publisher prentice hall