UNIT – II

SYSTEM ANALYSIS AND

DESIGN

Systems DevelopmentLife Cycle

(SDLC)

Systems Development

What is a system?

A collection of related components that interact to perform a task in order to accomplish a goal

A framework that describes the activities performed at each stage of a software development project.

STAGES IN SDLC

REQUIREMENT ANALYSIS

BY,

K>R>SHREENIVASAN.

Requirement Analysis

Analysis

A. Determine system requirements

B. Structure requirements

• 1. Process modeling

• 2. Logic modeling

• 3. Data modeling

C. Select best alternative

Requirements Analysis Goals

•Fully describe the current system

• Study and analyze the current system (gather and

study facts)

•Determine the ideal information system

• Identify resource constraints

•Define and prioritize requirements

• Inspire user confidence/ownership

Steps Involves in System Investigation

System planning and selection

Feasibility Study

Feasibility Report

Feasibility Analysis

They Result in Recognition of both benefits and risks inherent in the development and implementation of the proposed system

5 types of Feasibility

• Technical Feasibility

• Economic Feasibility

• Motivational Feasibility

• Schedule Feasibility

• Operational Feasibility

Technical Feasibility

• Analysis of Project Risk Relative To Technical Feasibility includes not only whether the technology is available on the market but also its “state of the art” both in absolute terms and relative to the company’s current technical Sophistication .

Economic Feasibility

• Will system provide benefits greater than the costs? The feasibility study presents intangible as well as Tangible benefits in a formal way . A relatively detailed analysis of the costs of both development and operations of the various alternatives is also presented .

Motivational Feasibility

• Organization is sufficiently motivated to support the development and implementation with user Participation, Resources, Training time, etc.

• An owner or champion for the application who has sufficient organizational power to provide the resources and motivate others to assist and cooperate usually demonstrates this motivation

Schedule Feasibility

• Organization can complete the development process in the time allowed for department .

• Adding development resources does not always reduce the development time; in fact, adding staff that cannot be used effectively may development because for time spent in communication

Operational Feasibility

• Will it work when installed? This analysis may involve a subjective assessment of the political and managerial environment in which the system will be implemented .

• In general, the greater the requirements for change in the user environment in which the system will be installed, the greater the risk of implementation failure.

INTERVIEWS

• Personal interviews are a direct method of obtaining information from people. By this the analyst learns about the existing system, problems and expectations.

• During an interview the analyst and the person being interviewed are meeting face to face.

• Interview has to be conducted at all levels with in organization from the president/ chief officer to the mail clerk.

Types of Interview

• Structured Interview

• Unstructured Interview

Types of Interviews

• Structured Interview

In these type of interviews, the interviewer has a specific set of questions to ask of the interviewee

• Unstructured Interview

These are conducted with only a general or subject in mind and with few, if any specific questions

Steps of Interviewing

• Step 1) Select Interviewees

• Step 2) Prepare for the Interview

• Step 3) Conduct the Interview

• Step 4)Follow Up on the Interview

Select Interviewees

• The end users of the proposed system should be interviewed. Attempt should be made to learn as much as possible about individual before the interview. Interview should last about 30 minutes to an hour. The interviews for higher management people should be shorter.

Prepare for the Interview

• A good preparation is the key to successful interview. The analyst should prepare an interview guide before the interview. An interview guide is a checklist of questions that the interviewer will ask the interviewee. Question should be carefully chosen and phrased.

Arranging Interview

i. Interview schedule and timings

ii. Location of interview

iii. Selection of interviewees and order of interviewing

iv. Objectively defined agenda

v. Sequence of questions

Conduct the Interview

Opening: It Is intended to motivate the interviewee to participate and communicate by establishing an ideal environment. There are 3 ways

a) Summarize the apparent problem and explain how the problem was discovered.

b) Offer an incentive or reward for participation

c) Ask the interviewee for advice or assistance.

Body: Interview body is the most time consuming phase. During this phase,youobtain the interviewee’s responses to the list of questions.All the verbal and non verbal responses of the interviewee should be monitored.

Conclusion: During the interview conclusion, you should express your appreciation and provide answers to any questions asked by the interviewee.

Follow Up on the Interview

To help maintain good rapport and trust with interviewee, you should send them a memo that summarizes the interview. In addition, the interviewees should be given the opportunity to offer additional information they may have failed to bring out during the interview.

ConclusionAdvantages of Interviews:It analyst an opportunity to motivate the interviewee to respond freely and openly to questions.

It allows the systems analyst to probe for more feedback from interviewee

It permit the system analyst to adapt or reword questions for each individuals

It give the analyst a opportunity to observe the interviewee’s non verbal communication

Disadvantages of Interviews:It is time consuming and costly fact finding approach

Success of interviews is highly dependent on the system analyst’s human relation skills.

Interviewing may be impractical due to the location of interviewees