Transcript Chapter 1 Assuming The Role Of The Systems Analyst

Chapter 1
Introduction to Systems
Design and Analysis
Systems Analysis and Design
Kendall and Kendall
Sixth Edition
Readings & Major Topics
Readings
Chapter 1 (p. 1) in the textbook
Major Topics
Information systems
SDLC (Systems Development Life Cycle)
Phases of analysis and design
CASE tools
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Information
 What is information?
 Domain dependent
Facts, concepts, or instructions; any sort of knowledge
or supposition which can be communicated.
 Organizational resource
 Must be managed as carefully as other resources (e.g.,
raw material, labor)
 Costs are associated with information processing
 Production, distribution, security, storage, retrieval, …
 Information processing must be managed to take full
advantage of its potential
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Systems Analysis & Design
Goals
Analyze data input, processing or
transforming data, data storage, and
information output within the context of a
particular business
Analyze, design, and implement
improvements in the functioning of a
business via the use of computerized
information systems
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How can we Analyze and Design
Systems?
Intuitive approach
Pros and Cons?
Systematic approach
Pros and cons?
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Systems Analysis and Design in
this Course
Systematic approach to identifying
problems, opportunities, and objectives;
analyzing the information flows in
organizations; and designing
computerized information systems to
solve a problem
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Systems Analyst
Performs systems analysis and design
Assesses how businesses function by
examining the inputting and processing
of data and the outputting of
information with the intent of improving
organizational processes
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Different Types of Systems Analysts
 Two major types
 Outside consultants to businesses
 Hired specifically to address information systems issues
within a business
 Supporting experts (within a business you are regularly
employed)
 Not a full-blown systems project, but rather entails a small
modification or decision affecting a single department
 Your role as a systems analyst: agent of change
Catalyst for change (i.e., improvements to the business
that can be done via information systems)
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Interactions of a Systems Analyst
A systems analyst interacts with users
at different levels in the organization
User managers
Operations workers
Systems managers
Systems designers
Programmers
….
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Qualities of a Systems Analyst
 Analysts are problem solvers.
 Communication skills
 Analysts must be ethical with users and customers
 ACM’s (Association of Computing Machinery) code of
ethics
…
 respect the privacy of others
Give comprehensive and thorough evaluations of
computer systems and their impacts, including
analysis of possible risks
…..
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Systems Development Life
Cycle (SDLC)
SDLC is a systematic approach to
solving business problems
It is divided into seven phases
Each phase has unique activities
A phase is never accomplished as a
separate phase
Several activities can occur simultaneously
Activities may be repeated
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Phase 1: Identifying problems,
opportunities, and objectives
 Identifying
 Problems: don’t want to address the wrong
problems
 Opportunities: situations that can be improved
 Objectives: how can the organization reach its
objectives via computerized IS
 Personnel involved
 Analyst
 User managers
 Systems managers
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Phase 2: Determining Information
Requirement
 Understand how the business functions and have
complete information on the people, goals, data, and
procedures
 Interview management, operations personnel
 Gather systems/operating documents
 Use questionnaires
 Observe the system and personnel involved
 Learn the details of the current system functions:
who (people involved), what (business activities),
where (environment in which the work takes place),
when (timing), how (procedures), and the why (why
is it done this way)
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Phase 2: Determining Information
Requirement (cont’d)
Personnel involved
Analyst
User managers
Operations workers
Systems managers
Information Analyst (phases 1 and 2)
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Phase 3: Analyzing Systems
Needs
 Analyzing system needs
 Create data flow diagrams
 Document procedural logic for data flow diagram
processes
 Complete the data dictionary
 Analyze structured decisions
 Make semistructured decisions (decisions taken
under risk)
 Prepare and present the system proposal
 Recommend the optimal solution to management
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Phase 3: Analyzing Systems
Needs (cont’d)
Analyst makes recommendations to
management
Management decide whether to continue
or not
Personnel involved
Analyst
User managers
Systems managers
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Phase 4: Designing the
Recommended System
 Accomplish the logical design of the
information system
 Design the user interface
 Design output
 Design input
 Design files and/or database
 Design control and backup procedures
 Produce decision trees or tables
 Produce program specifications
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Phase 4: Designing the
Recommended System (cont’d)
Personnel involved
Analyst
System designer
User managers
Operations workers
Systems managers
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Phase 5: Developing and
Documenting Software
 Develop any original software that is needed
 Design computer programs using structure
charts, Nassi-Schneiderman charts, and
pseudocode
 Walkthrough program design
 Write computer programs
 Document software with help files, procedure
manuals, and Web sites with Frequently Asked
Questions (FAQs)
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Phase 5: Developing and
Documenting Software (cont’d)
Personnel involved
Analyst
System designer
Programmers
Systems managers
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Phase 6: Testing and Maintaining
the system
 Testing and maintaining the system
 Test and debug computer programs
 Test the computer system
 Enhance system
 Personnel involved
 Analyst
 System designer
 Programmers
 Systems management
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System Maintenance
Maintenance: starts in phase 6 but
carried out routinely throughout the life
of the IS
System maintenance is
Removing undetected errors, and
Enhancing existing software
Time spent on maintenance typically
ranges from 48-60 percent of total time
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System Enhancements
Systems are enhanced for the following
reasons:
Adding additional features to the system
Business and governmental requirements
change over time
Technology, hardware, and software are
rapidly changing
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Phase 7: Implementing and
Evaluating the System
 Implementing and evaluating the system
 Plan conversion from the old system to the
new one
 Train users
 Purchase and install new equipment
 Convert files
 Install system
 Review and evaluate system: whether the
intended users are indeed using the system
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Phase 7: Implementing and
Evaluating the System (cont’d)
Personnel involved
Analyst
System designer
Programmers
User managers
Operations workers
Systems managers
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CASE Tools
 Computer-Aided Software Engineering (CASE)
 CASE tools are automated, microcomputer-based
software packages for systems analysis and
design
 Four reasons for using CASE tools are:
 To increase analyst productivity
 Facilitate communication among analysts and users
 Providing continuity between life cycle phases
 To assess the impact of maintenance
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CASE Tool Categories
CASE tools may be divided into several
categories
Upper CASE (also called front-end CASE)
tools, used to perform analysis and design
Lower CASE (also called back-end CASE).
These tools generate computer language
source code from CASE design
Integrated CASE, performing both upper
and lower CASE functions
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Upper CASE
Upper CASE tools
Create and modify the system design
Store data in a project repository
The repository is a collection of records,
elements, diagrams, screens, reports, and
other project information
These CASE tools model organizational
requirements and define system
boundaries
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Lower CASE
Lower CASE tools generate computer
source code from the CASE design
Source code may usually be generated
in several languages
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Lower CASE: Advantages of
Generating Code
Time to develop new systems decreases
The time to maintain generated code is less
than to maintain traditional systems
Computer programs may be generated in more
than one language
CASE design may be purchased from thirdparty vendors and tailored to organizational
needs
Generated code is free from program coding
errors
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Reverse Engineering
Reverse engineering is generating the
CASE design from computer program
code
Source code is examined, analyzed, and
converted into repository entities
Uses Computer-Assisted Reengineering
(CARE) software
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Reverse Engineering Produces
Depending on the tool set used:
Data structures and elements, describing
the files, records, and field
Screen designs, if the program is online
Report layouts for batch programs
A structure chart showing the hierarchy of
the modules in the program
Database design and relationships
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Advantages of Reverse
Engineering
It has the following advantages:
Reduced system maintenance time
Program documentation is produced for
loosely documented programs
Structured programs may be generated from
unstructured, older programs
Future system maintenance is easier to
implement
Unused portions of programs may be
eliminated
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