INTRODUCTION TO SYSTEM ANALYSIS AND DESIGN

- Manjot Kaur

REFERENCE BOOKS

1. Awad, EM: System Analysis and

Design, second edition

2. James .A. Senn : Analysis and

Design of information systems,

second edition

3. Jeffery L. Whitten: System

Analysis & Design Methods, fifth

edition

DEFINITION OF A SYSTEM

•‘A system is an orderly grouping of interdependent components linked together according to a plan to achieve a specific objective.’•Basically there are three major components in every system, namely input, processing and output.

CHARACTERISTICS OF A SYSTEM

• Organization

• Interaction

• Interdependence

• Integration

• Central Objective

ELEMENTS OF A SYSTEM

• Outputs and Inputs

• Processors

• Control

• Feedback

• Environment

•Boundaries and Interface

Dining Room

Storage Office

Kitchens

Counter

Boundary

Inputs:Food, labor,Cash, etc.

Outputs:Prepared food

Environment: customers, food distribution, banks, etc.

Interrelationship

Example: A fast food restaurant as a system

ELEMENTS OF A SYSTEM - AN EXAMPLE

• Describe your college as a system–What is the input?–What is output?–What is the boundary?–What are the components and their

relationship?–The environment?

TYPES OF SYSTEMS

• Physical or Abstract Systems

• Open or Closed Systems

•Formal or Informal systems (Man-made

Information Systems)

• Manual or Automated

TYPES OF SYSTEMS

Physical Systems • Tangible entities that maybe static or dynamic in

application

•Eg: Computer Systems, Vehicles, Companies,etc.

Abstract Systems• Conceptual or non physical entities

•Eg: Online Reservation system, library management system,

etc.

TYPES OF SYSTEMS

Open Systems • Has many interfaces with its environment

• Permits interaction across its boundary

Closed Systems• It is isolated from environmental influences

TYPES OF SYSTEMS

Formal Systems • Planned in advance & used according to a schedule

•System Policies & Procedures are documented well in

advance

•Informal Systems• It is not described by procedures

•Works on as need basis

TYPES OF SYSTEMS

Automated Systems•Does not require human intervention

•The whole process is automatic

•Eg: Traffic control systems, Information kiosks

Manual Systems • Requires human intervention

• eg: College Admission system

APPROACHES FOR DEVELOPMENT OF SYSTEMS

• Structured Analysis & Design (Model Driven)– Emphasizes the drawing of pictorial system models that

become the blueprint for designing & constructing an improved system

• Prototyping (Accelerated)– Building a scaled-down working version of the system

• Joint Application Design (JAD)— Users, Managers and Analysts work together — System requirements are reviewed

MODEL DRIVEN APPROACH

• Structured Analysis : • Organize tasks associated with requirements

determination• Process centered technique• Uses DFD & ERD as tools

• Structured Design• Utilizes graphic description(output of system analysis)• Focuses on development of programs consisting of

functionally independent modules• Uses modeling tool Structure Chart

DESIGN PRINCIPLES

• Modularity & Partitioning• Cohesion• Coupling• Span of Control• Shared use of functions

PROTOTYPE APPROACH

JOINT APPLICATION DEVELOPMENT

• Participants in a JAD meeting are:• JAD session leader• Users• Managers• Sponsors• System analysts• Other staff such as programmers, database

analysts, etc.

SYSTEM ANALYST

SYSTEM 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

ROLES OF A SYSTEM ANALYST

Change Agent

Investigator & Monitor

Architect

Psychologist

Motivator

Intermediary

SKILLS OF A SYSTEM ANALYST

Analytical Skills

Technical skills

Management skills

Interpersonal skills

ANALYTICAL SKILLS

There are four sets of Analytical skills:

System Study

Organizational Knowledge

Problem Identification

Problem Analyzing and Solving

System Study

The first step in systems study is to be able to identify

something as a system.

Identify where the boundary lies and all of the

relevant inputs & outputs

Visualizing a set of things and their relationship as a

system to translate the physical design into a logical

design

Organizational Knowledge

How organizations workPolicies

Terminologies, abbreviations, and acronyms

Short/long term strategy and plans

Role of technology

How the department operates, its purpose,

its relationship with other department

its relationship with customers and suppliers

Problem Identification

Problem is the difference between an existing (current) situation and desired (output) situation

The process of identifying problems is the process of defining differences, so problem solving is the process of finding a way to reduce differences

Analyst should able to compare the current in an organization to the desired situation.

Problem Analysis & Solving

Once the Problem has been identified, analyse the problem & determine how to solve it

Analyst should able to formulate alternative solutions to the problem & choose the best one

TECHNICAL SKILLS

Many aspects of the job as a system analyst are technically oriented.

The System Analyst should be familiar as possible with information technologies such as:• Microcomputer, micro station, workstation, mainframe

computers• Programming languages• Operating systems• Database and file management systems• Data communication standards• Software for local and wide networks• Web developing tools• Decision support system generators • Data analysis tools• Data design tools

MANAGEMENT SKILLS

System analysts are almost always members of project teams and are frequently asked to lead team

Management skills are very useful for anyone in a leadership role

There are four class of management skills:1- Resource Management2- Project Management3- Risk Management4- Change management

INTERPERSONAL SKILLSCommunication skills

Interviewing, Listening, and questionnaires

Written and oral presentations• Meeting agenda• Meeting minutes• Interview summaries• Requests for proposal from contractors and vendors

Working alone and with a team

Facilitating groups

Managing expectations

• Describe yourself in terms of your abilities at each of the following interpersonal skills:

• Working alone v/s working with a team• Interviewing, Listening, Writing, Presenting• Facilitating a group and Meeting expectations• Where are your strengths and weakness? Why?• What can you do to capitalize on your strengths

and strengthen areas where you are weak?

ASSIGNMENT

SYSTEM DEVELOPMENT LIFE CYCLE

SYSTEM LIFE CYCLE

An information system is “born” when a problem is recognized

After the system is developed, it grows until it reaches maturity

Eventually, a change in the nature of the problem or increasing maintenance costs degrade the value of the system, so it “dies” and a new or replacement system is born to take its place.

SYSTEM DEVELOPMENT LIFE CYCLE (SDLC)

System Development Life Cycle is an organizational process of developing and maintaining systems

It helps in establishing a system project plan, because it gives overall list of processes and sub-processes required developing a system.

SDLC PHASES

SDLC consists of mainly seven steps:

Problem Identification & SelectionProject Initiation & PlanningAnalysisLogical DesignPhysical DesignImplementationMaintenance

SDLC PHASES

The first step is problem identification

The intent is to identify the problem, determine its cause, and outline a strategy for solving it.

Includes a detailed and in-depth study in which the identification of user’s requirement and the limitations and problems of the present system are studied.

Problem Identification & Selection

The second step is project planning

The problems that are identified are investigated

Includes determination of scope of the proposed system

Project Initiation & Planning

Analysis is a detailed study of various operations performed by a system and their relationships within and outside the system

The objective of analysis is to determine exactly what must be done to solve the problem. Typically, the system’s logical elements (its boundaries, processes, and data) are defined during analysis.

Feasibility Study of the proposed system is also performed

Analysis

Types of Feasibility

Operational FeasibilityTechnical FeasibilityEconomic FeasibilitySchedule Feasibility

Operational Feasibility

Operational Feasibility means that a proposed system will be used effectively after it has been developed.– Does management or do users support the projects?

Do users see the need for change?– Will the system result in a work force reduction?– Will the system require training for users?– Will customers experience adverse effect in anyway,

either temporarily or permanently.

Technical Feasibility

The technical resources needed to develop, purchase, install, or operate the system. – Does the company have the necessary hardware,

software, and network resources?– Does the company have the needed technical

expertise?– Will the hardware and software environment be

reliable?– Will the system be able to handle future transaction

volume and company growth?

Economic Feasibility

Economic Feasibility means that the projected benefits of the proposed system outweigh the estimated costs usually considered the total cost of ownership (TCO).– People, including IT staff and users– Hardware and equipment– Software– Formal and informal training – Licenses and fees – Consulting expenses– Facility costs – The estimated cost of not developing the system or

postponing the project

Schedule Feasibility

Schedule Feasibility means that a project can be implemented in an acceptable time.– Can the company or the IT team control the

factor that effect schedule feasibility?– What condition must be satisfied during the

development of the system?– Will an accelerated schedule pose any risk?– Will the project manager be appointed?

System DesignThe objective of design is to determine how the

problem will be solved

Based on the user requirements and the detailed analysis of a new system, the new system must be designed

It is a most crucial phase in the development of a system

Normally, the design proceeds in two stages : Logical : concentrates on the business aspects of

the system(functionality)Physical: concentrates on the technical aspects of

the system(programming language, databases, etc.)

ImplementationImplementation includes Coding , Testing &

InstallationCoding is also called the programming phase in

which the programmer converts the system specifications into computer instructions

Before actually implementing the new system into operations, a test run of the system is done removing all the bugs, if any

During installation phase, all the programs of the system are loaded onto the user's computer

After loading the system, training of the users starts

Maintenance

Maintenance is necessary to eliminate errors in the system during its working life and to tune the system to any variations in its working environment

It is the review of the system from time to time

Maintenance is of three types: CorrectiveAdaptivePerfective

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