Welcome to
SYSTEMS ANALYSIS AND DESIGN
Facilitator: Dr. Samali V. Mlay
Topic 1 Learning Outcome
By the end of the lecture, students should be able to;
Define components, classifications and examples of systems
Define systems analysis and design
Describe the responsibilities of a systems Analyst
Detail the users of systems
Detail participants in Information System Development
Identify the need for developing a new I.S
Differentiate between structural and Object oriented design
Definition of a system
The word system has its origin in Greek roots that means
“standing together”.
A system is a set of interrelated components working
together to achieve a common objective.
A system has some components and they are linked
together in some order (structure). Also a system has a
purpose for its existence, which is to achieve the goals
(objectives) that are set out for it.
Components of a System
All systems comprise of Input, Processes and Output
Other components may include feedback, system
boundary, system environment.
Systems can be broken down into subsystems
Process
input Output
Examples of systems
Computer based systems Religious systems
Economic systems Social systems
Educational systems Psychological systems
Financial systems Cultural systems
Communications systems Food distribution systems
Environmental systems Transportation systems
Medical systems Entertainment systems
Corporate systems Government systems
Insurance systems
Information Systems
The main purpose of information systems is to manage
data for a particular organization, maintaining files,
producing information and reports etc.
They can be grouped into formal (deals with the flow
of information from top to lower management),
informal (employee based), and computer based
information systems (depends on the use of
computers for managing business applications).
Information Systems
A computer based business system involves six
interdependent elements. i.e. hardware (machines),
software, people (programmers, managers or users),
procedures, data, and information (processed data).
System analysis relies heavily upon computers to
solve problems. For these types of systems, an
analyst should have a sound understanding of
computer technologies.
Examples of Information systems
Executive Support Systems
Management Information Systems
Decision Support Systems
Knowledge work systems
Office Automation Systems
Transaction Processing Systems
Geographical Information Systems
Expert systems
Group support systems
Artificial intelligence systems (robotics, learning systems, neural systems,
vision systems etc)
etc
Applications of Information Systems
Reservation systems
Automated Teller Machines
Electronic Point of Sale
Supply Chain Management System
Customer Relationship Management Systems
Scheduling systems - electronic calendars
Communication system - E-Mail, voice mail,
groupware or videoconferencing.
Applications of Information Systems
Payroll system
Employee records system
Benefit systems
Career path systems
Personnel training systems
Engineering workstations
Investment workstations
Applications of Information Systems
Accounting system like Sun Systems (Vision Alert).
Inventory Monitoring systems/Inventory
Management Systems.
Order processing systems
Market Analysis systems
Pricing Analysis systems
Applications of Information Systems
Computer Aided Design (CAD) - product design
using computer graphics.
Virtual Reality - Interactive software that creates
photorealistic simulations of real world objects
(Virtual Reality Modeling Language: VRML)
Virtual Medical Diagnosis
Robotics
Brief Introduction To Systems Analysis And
Design
The development of any information system can be
put into two major phases: analysis and Design.
During analysis phase the complete functioning of
the system is understood and requirements are
defined which leads to designing of a new system.
Hence the development process of a system is
also known as System Analysis and Design
process.
System Analysis
Here emphasis is given to understanding the details
of an existing system or a proposed one and then
deciding whether the proposed system is desirable or
not and whether the existing system needs
improvements.
Thus, system analysis is the process of
investigating a system, identifying problems,
and using the information to recommend
improvements to the system.
System Design
System design is the process of planning
a new business system or one to replace
or complement an existing system.
After the proposed system is analyzed and
designed, the actual implementation of the system
occurs. After implementation, working system is
available and it requires timely maintenance.
System analysis and design
Analysis specifies what the system
should do. Design states how to
accomplish the objective.
System Analysis and Design, mainly
deals with the software development
activities
Role Of System Analyst
The system analyst is the person (or persons) who
guides through the development of an IS inline with
the goals of the organisation.
Most common responsibilities of System Analyst
are;
System analysis: It includes system's study in order
to get facts about business activities. It is about
getting information and determining requirements.
Here the responsibility includes only requirement
determination, not the design of the system.
Role Of System Analyst
System design: Here the Analyst is responsible
for the designing of the new system/application.
Systems programming: Here Analyst is also
required to perform as a programmer, where he
actually writes the code to implement the design
of the proposed application.
Skills of System Analysts
A system analyst needs to be multifaceted person with varied
skills required at various stages of the life cycle. Other skills
needed are;
Business knowledge: he should be familiar with the general
functioning of the business.
Interpersonal skills: for interacting with the users and
extracting the requirements out of them
Problem solving skills: A system analyst should have enough
problem solving skills for defining the alternate solutions to
the system and also for the problems occurring at the various
stages of the development process.
Skills of System Analysts…
Working knowledge of IT – to be able to show end
users how the new technology will work
Computer programming knowledge –to be able to
link users to programmers
Communication skills – skilled in business writing,
technical writing, interviewing, presenting and
listening
Flexibility and Adaptability to various systems
Character and ethics
The Users of a System (System End
Users)
These are the people who use computers to perform their
jobs, like desktop operators.
Further, end users can be divided into various categories.
Hands-on users. They actually interact with the system.
They are the people who feed in the input data and get
output data.
Indirect end users who do not interact with the systems
hardware and software. However, these users benefit
from the results of these systems. These types of users
can be managers of organization using that system.
The Users of a System (System End
Users)
Those who have management responsibilities for
application systems. These oversee investment in the
development or use of the system.
Senior managers. They are responsible for evaluating
organization's exposure to risk from the systems
failure.
Participants in
Systems Development
[Figure 12.1]
Participants in
Systems Development
Stakeholders
Individuals who ultimately benefit from the systems
development project, vendors and suppliers
Users
Individuals who interact with the system regularly
Owners /Sponsors/Top Management
Financers of the Project
Systems analyst and designer
A professional who specializes in analyzing and designing
business systems
Participants in
Systems Development
Programmer
The individual responsible for modifying or developing
programs to satisfy user requirements
Technical Specialist
Experts in certain types of technology e.g. Telecom,
databases, Mobile computing etc.
Vendors
They provide/sell software and hardware to the
organisation.
Why Initiate a Systems
Development Project?
[Figure 12.2]
Information Systems Planning
Translation of
strategic and
organizational goals
into systems
development
initiatives [Figure 12.3]
The Steps of IS Planning
Strategic plan
Develop objectives
Identify IS projects
Set priorities
Analyze resource [Figure 12.4]
requirements
Set schedules
Develop planning
document
Information Systems Planning
Developing a competitive advantage
requires creative and critical analysis.
Creative analysis
The investigation of new approaches to existing
problems
Critical analysis
Unbiased and careful questioning of whether the
current system is effective and efficient and whether a
new system should be developed.
Establishing Objectives for
Systems Development
The impact a system has on an organization’s
ability to meet its goals determines the true value
of that system to the organization.
Mission critical systems
Systems that play a pivotal role in continued operation and
goal attainment
Establishing Objectives for
Systems Development…
Performance objectives
Quality or usefulness of the output
Quality or usefulness of the format of the output
Speed at which output is generated
Cost objectives
Development costs
Costs related to the uniqueness of the system application
Fixed investments in hardware and related equipment
Ongoing operating costs of the system (Total Cost of
Ownership)
SAAD APPROACHES
Two design approaches are used
Structured/Procedural Design (the older but most
commonly used)
Object Oriented Design (Newer approach, about only
35% of IS projects)
Structured/Procedural Design
Structured design adopts a formal step-by-step
approach to the SDLC phases and activities.
At the completion of each activity or phase, a
document is produced that must be approved by the
stakeholders before moving to the next phase.
The center of the structured approach is the process
model that depicts the business processes of a system
The main focus of this class (to cover more details)
Object Oriented Design
OOD allows large-scale applications to be developed
in independent modules.
Object-oriented decomposition provides a method to
decompose a complex arrangement by the primary
objects apparent in the system
Once the objects are defined and the system
functionality is assigned, major components of the
software system are developed independently.
It is iterative and incremental using Unified
Modeling Languages (UML)
Object Oriented Design…
Object-oriented analysis (OOA) strives to describe
what the system should do in terms of key objects in
the problem domain
Object oriented design (OOD) strives to describe
how the system will work using these objects.
Difference between Structured Design
and OOD
Structured design works when all requirements must be
determined before design can start (top-down approach),
while OOD may be changed.
Structured design specifies all steps to be taken in a
program while OOD just specifies the solution
Structured design is based on computer program structures
with separate program steps (processes) and data while
OOD combines the programs with data
Structured design suggest developing software from scratch
while OOD suggests reusing existing code.
