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© University of Colombo School of

Computing

References

Ref_1 : System Analysis and DesignMethodsBy Whitten, Bentley, Dittman

ISBN 0-07-044539-7 (5th

Edition)

Ref_2 : System Analysis and Design ByIgor Hawryszkiewycz (4th

Edition) ISBN 81-203-1670-3

Ref_3 : Practical SSADM Version 4 AComplete Tutorial Guide By PhilipL Weaver ISBN 0-273-60095-8

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Introduction toSystem Development

Environment

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Computing

Introduction

Earlier applications

Keeping records

of transactions

Airline Reservations Keeping records

of Stock

Information Systems

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Computing

Information Systems

Introduction

Production HRM - Training Telephone Integration

Computers are now becoming part of virtuallyevery activity in organization

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Information System…

Information SystemIt is an arrangement of

People ProcessInterface Data Technology

• Improve day to day operations

• problem solving and decision making

Network

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Computing

Systems Design Environment…

• Stakeholders cont..

Use the system to

perform or support the

work to be completed.

System Users

or Clients

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Computing



System Owner

Owns the system.

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Computing



System Designer

Design the system tomeet the users

requirements

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Computing



System Designer

Design the computer files,

databases, inputs,

outputs, screens,

networks, and programs

that will meet the systemusers requirements.

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Computing



System Builders

Construct, test and deliver the Information System

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Computing



Systems Analysts

People who understand

both business andcomputing

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Computing



Systems Analysts

Bridge the communication

gap that exists betweennon technical and

technical people involved

with building systems.

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Computing



Systems Analysts

- Identify the problem

- Analyze and understand theproblem

- Identify the solution

requirements

- Identify alternative solutions

- Design and implement the

best solution

- Evaluate the result

What does a systems analyst

do?

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Computing



Vendors

Consultants

Sell Hardware, Software, and services

to business

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Computing

Information System Development Teams usually consists

of the these 6 Stakeholders


System User

System Designer

VendorsSystem Builders

System Analysts Consultants

System Owner

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Computing

Outsourcing

Contracting with an outside vendor to assume

responsibility…


In house developer Out side vendors

Less costly

Value added

T e c h n o l o

g y

S

o u r c

e

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Computing


Legacy systems

• Old Information System Applications

• Use Old or Outdated

Technologies that were popular

at the time.

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Computing


Legacy systems cont.

• Many complex legacy systems yet to beupgraded to new technologies because of – Cost,

– Skills and – People required

• Force to change – to reflect new or changing

business requirements. – Year 2000 problem (Y2K)

– Euro conversion

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Computing


Legacy systems cont.

Y2K problem – Many computers and applications stored

date with only 2 digits.

(e.g. 99 =1999) – Problems : when the millennium changed

(e.g. 03=2003)

Born in 1978

Age? -75, 0, 75

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Types of Information Systems

Transaction Process

System (TPS)

Management Information

System (MIS)Decision Support System

(DSS)

Expert System (ES)

Office Automation andWork Group System

Centralized Systems

Distributed Systems

Client Server SystemsNetwork Computing System

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Types of Information System

Transaction Process Systems (TPS)Information systems that capture and process data about business

transactions

Examples

Airline

Reservations

Retailpoint of sale

Bank deposit andwithdrawal

BIT @UCSC Course

Registration

Transaction

----------

-------

---------

----------

---------

Information

C a p t u

r e D a t a

P r o c e

s s

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Management Information System (MIS)MIS is an information system application that provides for management

oriented reporting.

Examples

Inventory reportingProduction scheduling Sales forecast

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Computing

Types of Information SystemManagement Information System (MIS) cont..

Normally produced from a shared database.

Information

Summery

informationDetail information

Exception

information

MIS

Produces

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Decision Support System (DSS)• Provides its user with decision-oriented information whenever

decision making situation arises.• Sometimes called executive information system.

Executes at work

With DSS

Types of Support

Identification of problems

or decision makingopportunities

Identification of possible

solutions and decisions

access to information

needed to solve a

problem or make adecision

Analysis of possible

decision that willaffect the decision

Simulation of possible solutions

and their likely

results.

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Expert System (ES)-- An expert system is a programmed decision making information

system.

-- It capture and reproduces the knowledge and expertise of a decision

maker and-- Simulates the “thinking” of the expert.

I am a computer,

sorry no…. No…I am a human Artificial Intelligent (AI)

Technology that captures,

stores, and provides access

to the reasoning of the

experts.

Implemented with

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Types of Information SystemOffice Automation Systems-- Support wide range of business office activities

-- Provide facilities for improved work flow and communication between workers

-- Workers may not be located in the same office.

f a c s i m

l e

E - M a i l

I m

a g i

n g E l e c t r o n

i c d o c u

m e n t

W o r k g r o u p

c o m p

u t i n g

W o r k g r o

u p s c h

e d u l i n g

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Types of Information SystemOffice Automation Systems

Designed to support

--- Individuals

--- Workgroups Personal Information Systems- for a single user

Work group Information Systems- for a work group

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Centralized Systems

User

I have all

system data

I am doing all

processing

Provide

interfaces

Databases

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Distributed Systems

1. Client Server SystemsSolutions are distributed between client PC’s and one or more servers.

Accounts

Sales

Design

Construction

-- Components of an information system-- Processing workload required to

support the components

Distributedto multiple

locations

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Computing

Distributed Systems

Client Server Systems cont..

Clients may be thin or flat

Acts only as

a terminal

Almost all PCs

e.g. Windows terminal

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Distributed Systems

• Presentation and presentation logic layers are implemented in a client

side web browser

• The presentation logic layer then connects to the application logiclayer that run on an application server,

• Subsequently connects to the database server/s

1. Network Computing Systems

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Processing Types

1. Batch Processing

The data entered is collected

into files called batches. Eachfile is processed as a batch of

many transactions.

Super market-Batch processing

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Computing

Processing Types

2. Online Processing

ATM-Real time processing

The captured data is processed

immediately.

D l P

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Computing

Development Process

Tools

Methods

Most Effective

Way of

Building

Methodologies• have a predefined set of steps, and

• a Collection of tools

used to design a system

It ensures that systems are built in the most effective way.

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Computing

Development Processcont.

Methodologies provide the organizers

framework for systems development.

• Defines :

♥

The stages into which the development will bebroken

♥The tasks to be performed.

♥The deliverables from these tasks♥Standards to be used

♥Quality checks to be applied .

Etc.

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Computing

Development Process cont.

Software systems that assists analysts and

designer to build computer based informationsystem.

Tools

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Development Process cont.

General Aim :

Decrease the human effort required to developsoftware.

and/or increase the quality of software

Tools

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