10390_CHAP1 Assuming the Roles of SA for Upload (2nd Sem 09-10) (1)

8/8/2019 10390_CHAP1 Assuming the Roles of SA for Upload (2nd Sem 09-10) (1)

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Chapter 1: Assuming the Roles of

Systems AnalystSystems Analysis and Design with Prototyping 1


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Categories ofInformation Systems

Information systems fall into one of the following eight categories:

- Transaction processing systems (TPS)

- Office automation systems (OAS)

- Knowledge work systems (KWS)

- Management information systems (MIS)

- Decision support systems (DSS)

- Expert systems (ES)

- Executive support systems (ESS)

- Group decision support systems (GDSS)

- Computer Supported Collaborative Work Systems


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TPS

KWS

OAS

MIS

ES

DSS

CSCWS

ESS

GDSS

Operational

Knowledge

High - level

Strategic


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Transaction processing systems(TPS)

- process large amount of data for routine business transaction toeliminate tedious operation andreduce time required to performthese operations manually. (e.g.payroll, inventory)

Office automation systems (OAS)

- supports data workers to analyzeinformation to transform data andmanipulate it. (e.g. word

processing, spreadsheet, desktoppublishing, email, voice mail, andvideo conferencing)


Knowledge work systems (KWS)

- supports professional workers suchas scientists, engineers, doctors byaiding them in their efforts to createnew knowledge and allowing them tocontribute to their organization and tothe society

Management information systems(MIS)

- supports broader spectrum of organizational tasks includingdecision analysis and decision-making to integrating functionalitiesof people, software and hardware

- MIS includes TPS

- Users of MIS use a commondatabase


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Decision support systems (DSS)

- a more closely-tailored system forthe persons or group to arrive at asound decisions.

- Similar to MIS : both depends ondatabase as a source of data

- Different to MIS: DSS emphasizeson the support of decision-makingin all it phases

Expert systems (ES) / Knowledge-based System

- captures the knowledge of an

expert for solving a particular problem experienced in anorganization. ES originates fromthe branch of Computer Science,which is Artificial Intelligence (AI).ES selects the best solution to aproblem. Components of ES knowledge base and inference

engine


Group decision support systems(GDSS) and Computer SupportedCollaborative Work Systems(CSCWS)

- bring a group together to solveproblems with the help of polling,questionnaire, brainstorming,

scenario creation.

- used in special rooms equipped in anumber of different configuration andpermits group members to interactwith electronic equipments andspecialized software (groupware) forgroup activity facilitation.

- for unstructured and semi-structuredproblems


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Executive support systems(ESS)

- helps executives organize theinteraction with externalenvironment by providing

graphical and communicationreports to arrive at strategicdecisions.



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New Technologies

New technologies are being integrated into traditional

systems

- Ecommerce uses the Web to perform business activities

- Enterprise Resource Planning (ERP) has the goal of integrating many

different information systems within the corporation

- Wireless and handheld devices, including mobile commerce

(mcommerce / wireless ecommerce)

- Open source software


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Advantages of Using the Web

The benefits of using the Web are

Increasing awareness of the availability of the service, product, industry,

person, or group

24-hour access for users

Standard interface design

Creating a global system


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Nature of Analysis and Design

Systems analysis and design isa systematic approach toidentifying problems,opportunities, and objectives;analyzing the information flows

in organizations; and designingcomputerized informationsystems to solve a problem.

Systems analysts act as

- Outside consultants to

businesses

- Supporting experts within a

business- As change agents

Analysts are problem solvers, and

require communication skills

Analysts must be ethical with users and

customers With adequate knowledge in

programming

Highly motivated and with self -

discipline


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Systems Development Life Cycle

a systematic approach to solving business problems

a phased approach to analysis and design that holds that systems are

best developed through the use of a specific cycle of analyst and user

activities

- Each phase has unique activities;

- Each phase is never accomplished as a separate step;

- Activities can occur simultaneously, and activities may be repeated;

SDLC is accomplished in phases and not in separate

steps.


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SDLC PHASES

1.Identifying problems, opportunities,and objectives

2.Determining informationrequirements

3.Analyzing system needs

4.Designing the recommendedsystem

5.Developing and documentingsoftware

6.Testing and maintaining the system

7.Implementing and evaluating thesystem


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Phase 1:Identifying problems, opportunities, and objectives

Problems

Opportunities

Objectives

Personnel involved- Analyst

- User management

- Systems management

Activities

- Interview user management- Summarize knowledge obtained

- Estimate scope of the project

- Document results

Output

Feasibility report containing problem

definition and summarizing the

objectives

Management must make a decision

whether to proceed with the proposed

project. If faced with inadequate

budget or if the problem does not

require a computerized system, the

system project does not proceed any

further


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Phase 2:Determining information requirements

Understand what information users

need to perform their job

Know the details of the current

system functions

Investigating hard data

- gather systems / operating

documents

- Use questionnaires

Interview management, operations

personnel

Observe the system and personnel

involved; office environment

Learn the following:

Who people involved

What business activity

Where the environment in which the

work takes place

When - timing

How how the current procedures are

performed

Why - why the business uses the current

system


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Personnel involved

- Analyst

- User management

- User operations workers


Phase 2:Determining information requirements


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Phase 3:Analyzing system needs

Document procedural logic for data

flow diagram processes

Complete the data dictionary

Analyze structured and semi-

structured decisions

Prepare and present the system

proposal and cost benefit analysis

Recommend the optimal solution to

management

Personnel involved

- Analyst

- User management



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Phase 4:Designing the recommended system

Design the user interface

- Design output

- Design input

Design files and/or database Design system controls and backup

procedures

Produce program specifications

Produce decision trees or tables,system flowchart / dataflow

diagrams

Personnel involved

- Analyst

- System designer

- User management

- User operations workers



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Phase 5:Developing and documenting software

Design computer programs using

structure charts and pseudo code

Walkthrough program design

Write computer programs

Document software with help files,

procedure manuals, and Web sites

with Frequently Asked Questions

Personnel involved

- Analyst

- System designer

- Programmers



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Phase 6: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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Phase 7:Implementing and evaluating the system

Plan conversion

Train users

Purchase and install new equipment

Convert files

Install system

Review and evaluate system


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Conversion Strategies

Pilot- trial system implemented in a

subset of the overall

operation, such as an office orgeographic area.

Immediate- To convert from the old

system to the new one on agiven date. Applicable only

for small firms or small

system.

Phased- The new system is put into use

one part at a time. Applicable

for large-scale system.

Parallel- The old system be maintained

until the new one is fully

checked out.


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System Maintenance

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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Reverse engineering and Reengineering

Reverse engineering and reengineering are

methods for extending the life of older programs,

called legacy software.

-Reverse engineering is the opposite of code

generation

-Reengineering refers to the complete process of

converting program code to the CASE Design,modifying the design, and regenerating the new

program code.


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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


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Reverse Engineering Produces

- 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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CASE Tools

- 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 severalcategories

- 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 sourcecode from CASE design

- Integrated CASE, performing both upper andlower CASE functions


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UpperCASE

- 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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LowerCASE

Lower CASE tools generate computer source code

from the CASE design

Source code may usually be generated in severallanguages


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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 morethan one language

- CASE design may be purchased from third-party

vendors and tailored to organizational needs- Generated code is free from program coding

errors


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Object-Oriented Analysis and Design

Object-oriented (O-O) analysis and design is used to build object-

oriented programs

This includes not only data but the instructions about operations that

manipulate the data


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Types ofObject-Oriented Analysisand Design

- Object-oriented analysis (OOA)

- Object-oriented design (OOD)

- The Unified ModelingLanguage (UM

L), astandardized object-oriented modeling language


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Rapid Application Development

Rapid Application development

(RAD) is an object-oriented

approach to systems development


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Nature of Analysis and Design

Structured analysis and design provides a

systematic approach to developing systems and is

cyclic in nature

Analysis and design errors detected in the later

phases of the systems development life cycle cost

more to fix than if detected in earlier phases


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Alternate Methodologies

- Prototyping

- ETHICS

- Project champions- Soft Systems Methodology

- Multi-view

10390_CHAP1 Assuming the Roles of SA for Upload (2nd Sem 09-10) (1)

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