System Analysis and Design
Introduction to System Analysis
and Design
(Definition of System & information
system components)
- Dr. Mahmoud Abu-Arra
- Mr. Ahmad Al-Ghoul
learning Objectives
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Describe the characteristics of system
Define an information system and
describe its components
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introduction
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Before talking about the characteristics of systems, and information system
components let us have a historical view for the system analysis and
design.
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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
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second step 1960s
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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
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Third step 1970s
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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
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Fourth step 1980s
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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 developer’s job went through a transition from builder to integrator
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introduction
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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
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Sixth step the new century
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The focus on developing systems for the Internet and for firm’s
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 don’t even run the application inhouse, 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
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A system interrelated components working
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Information system (IS)
together for a common purpose
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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
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Systems are made up of interrelated subsystems (e.g. a nuclear
reactor is composed of boilers, reactor components etc.)
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Functional decomposition – dividing a system into components
based on subsystems (which are in turn further divided into
subsystems)
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Functional & Non-Functional components of a system
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System boundary – the separation between a system and its
environment (where inputs and outputs cross)
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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
Automation
boundary
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Manual Part of the System
Automated Part of
the System
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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
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Information systems have five key
components: hardware, software, data,
processes, and people
data
software
people
processes
hardware
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Information System Components
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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
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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
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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
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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
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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
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People
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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
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Internal users include administrators, managers, technicians,
sales staff, and corporate officers
External users include customers who track their orders on
the company’s Web site and suppliers who use a customer’s
system to plan their manufacturing schedules.
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Sequence Summary
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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
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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
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