Modern Systems Analysis and Design Ch1€¦ · Systems Development Life Cycle (SDLC) (Cont.)...
Transcript of Modern Systems Analysis and Design Ch1€¦ · Systems Development Life Cycle (SDLC) (Cont.)...
Chapter 1- (Part 1)
The Systems Development
Environment
Modern Systems Analysis
and Design Sixth Edition
Jeffrey A. Hoffer
Joey F. George
Joseph S. Valacich
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Learning Objectives
Introduction
Define the usage of information systems analysis and design.
Describe the information Systems Development Life Cycle (SDLC).
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Data, Information, and Knowledge
Data: raw facts
Information: collection of facts organized in
such a way that they have value beyond(وراء)
the facts themselves.
Knowledge: awareness(الوعي والمعرفة) and
understanding of a set of information and ways
that information can be made useful to support a
specific task or reach a decision
Introduction
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Figure : The Process of Transforming Data into Information
Data, Information, and Knowledge
(continued)
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System Concepts
System
A set of elements or components that interact
to accomplish goals
Components of a system
Input
Processing
Output
Feedback
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Input, Processing, Output, Feedback
Input: activity of gathering and capturing raw
data
Processing: converting or transforming data
into useful outputs
Output: production of useful information, usually
in the form of documents and reports
Feedback: output that is used to make changes
to input or processing activities
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System Concepts (continued)
Components of a System
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What Is An Information System?
The Components of an Information System
An Information System
A set of interrelated components that collect,
manipulate, and disseminate(نشر), store and
process data into information, and provide
feedback to meet an objective
System users, business managers, and
information systems professionals must work
together to build a successful information system.
Example: A payroll system, for example, collects information on employees and their work, processes and stores that information, and then produces paychecks and payroll reports for the organization.
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Computer-based information system (CBIS)
A single set of hardware, software, databases,
telecommunications, people, and procedures
that are configured to collect, manipulate, store,
and process data into information.
Computer-based Information System (CBIS):
An information system that uses computer
technology to perform some or all of its
intended(مقصودة) tasks.
Examples: Airline reservation systems.
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Computer-Based Information Systems (cont.)
The Components of a Computer-Based Information System
Systems analysis and design
Systems analysis and design – the
process of planning, analysis, designing,
building, and maintaining information
system.
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Information Systems Analysis and Design
Complex organizational process
Used to develop and maintain computer-based information systems
Used by a team of business and systems professionals
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Introduction (Cont.)
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FIGURE 1-1 An organizational approach to systems analysis and
design is driven by methodologies(Phases), techniques(Method), and tools (ex. UML)
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A Modern Approach to Systems Analysis and
Design
1950s: focus on efficient(كفاءة) automation of existing processes
1960s: advent of 3GL, faster and more reliable(وثوقية واعتمادية) computers
1970s: system development becomes more like an engineering discipline(انضباط)
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A Modern Approach to Systems Analysis
and Design (Cont.)
1980s: major breakthrough with 4GL, CASE tools, object oriented methods
1990s: focus on system integration, GUI (Graphical User Interface ( applications, client/server platforms, Internet
The new century: Web application development, wireless PDAs (personal data assistant) , component-based applications
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A Modern Approach to Systems Analysis
and Design (Cont.)
Application Software
Computer software designed to support
organizational functions or processes
Systems Analyst
Organizational role most responsible for
analysis and design of information systems
Role of the Systems Analyst
Study problems and needs of an organization
Determine best approach to improving organization
through use of:
People
Methods
Information technology
Help system users and managers define their
requirements for new or enhanced systems
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Skills of a Successful Systems Analyst Analytical
Understanding of organizations
Problem-solving skills
System thinking
Ability to see organizations and information systems as systems
Technical
Understanding of potential and limitations of technology
Managerial
Ability to manage projects, resources, risk and change
Interpersonal (بين األشخاص)
Effective written and oral communication skills
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Developing Information Systems
System Development Methodology is a standard
process followed in an organization to conduct all
the steps necessary to analyze, design, implement,
and maintain information systems.
System Development Life Cycle
Systems Development Life Cycle (SDLC)
Traditional methodology used to develop,
maintain, and replace information systems.
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System Development Life Cycle
phases
Following are the different phases of System Development Life Cycle :
Planning
Analysis
Design
Implementation
Maintenance
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SDLC ’s Phases
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Systems Development Life Cycle (SDLC)
(Cont.)
1\ Planning – an organization’s total
information system needs are identified,
analyzed, prioritized, and arranged.
Phase of planning:
User request
Feasibility study
Project Plan
Project Proposal
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Systems Development Life Cycle(SDLC) (Cont.)
Planning:
The problems in the old system like:
The difficulty of using the system
System slowdowns
High cost in the operation of the system
Frequent failure in the system
Appearance a new technology useful for the goals of
the system
Shortage in output
Lack of security in
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Planning In this phase, someone identifies the need for a
new or enhanced system.
The project leader and initial team of system analyst produce a specific plan for a proposed system project.
A detailed plan is also developed for conducting the remaining phases of the SDLC for the proposed system.
Also, feasibility study conducted in this phase.
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System Development Feasibility Study
Feasibility study
A study that determines whether a requested
system makes economic and operational
sense for an organization.
In the process of feasibility study, the cost and benefits are estimated with greater accuracy(بدقة).
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Systems Development Life Cycle (SDLC)
(Cont.)
Analysis – system requirements are studied and structured
WHAT SHOULD THE SYSTEM CONTAIN ?
REQUIREMENTS ANALYSIS
DATA COLLECTION
INTERVIEWS, QUESTIONNAIRES, JAD,..
PROBLEM
USERS DON’T ALWAYS KNOW WHAT THEY WANT
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Analysis
The first is requirements determination which the system analyst work with users to determine what the users want from the proposed system.
Next the system analyst study the requirements and structure them according to their interrelationships.
Then system analyst generate alternative initial design to match the requirements.
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Systems Development Life Cycle(SDLC) (Cont.)
System Design The description of the recommended
alternative solutions is converted into logical and then physical system specification.
You must design all aspects of the system from input and output screens to reports, database, and computer processes.
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Systems Development Life Cycle (SDLC) (Cont.)
Logical design – Functional, detailed specifications of all system elements (data, processes, input, outputs)
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Systems Development Life Cycle (SDLC) (Cont.)
Physical design – the logical specifications of
the system from logical design are transformed
into the technology-specific details from which
all programming and system construction can
be accomplished(إنجاز)
Technical, detailed specifications of all system
elements (programs, files, network, system
software).
Systems Development Life Cycle (SDLC) (Cont.)
Implementation
Detailed model or detailed written specifications are turned to programmer as the first part of implementation phase.
Implementation includes coding, testing, and installation.
Coding: programmers write the programs that make up the system.
Testing: programmers and analysts test individual programs and the entire system in order to find and correct the errors.
Installation: the new system becomes a part of the daily activities of the organization.
.
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Systems Development Life Cycle (SDLC) (Cont.)
Maintenance
An information system is systematically repaired and improved.
When a system is operate in organization, users sometimes find problems with how it works and often think of better ways to perform its functions.
Programmers make the changes that users ask for and modify the system to reflect changing business condition.
So the final phase of SDLC improve information system.
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FIGURE 1-8
The heart of systems development
Chapter 1
The Heart of the Systems Development Process
Current practice combines analysis, design, and implementation
into a single iterative and parallel process of activities.
FIGURE 1-7
The analysis–design–code–test loop
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Summary
In this first part of chapter you learned
how to: Define information systems analysis and design.
Describe the information Systems Development Life Cycle (SDLC).