To Understand Different System Life Cycles

Published Date: 02 Nov 2017

The waterfall model is a sequential design which is mostly used in software development processes because it is very easy to understand. In waterfall the progress can be seen going downwards like a water fall and the progress starts from the user requirements where the analysis collects the information from the client. Then the analysis will collect the software requirements e.g. what do they need for their software department.

Then the analysis makes architecture design, the outline of the program so that they can get an idea how the program will look. After that the analysis makes a detailed design and does the coding. When they complete the detailed design they show to the client that there program will look like this and if the client accepts then the analysis will do the final testing to check if there is any problem and then it’s ready for delivery.

ADVANTAGES OF WATERFALL MODEL

It is very easy to understand and implement.

In this model, output is generated after ever stage so it is highly visibility.

This model is good where quality is more important as compared to cost.

Works well on mature products and weak team.

DISADVANTAGES OF WATERFALL MODEL

If any fault is there in the software it is very costly to go back and correct it.

Difficult to integrate risk management.

Idealized, doesn’t match reality well.

B)

The system lifecycle models, that don’t have any specific structure, are:

Code-and-Fix

Agile

Extreme programming (XP)

COTS

CODE-and-FIX

Code-and-fix model is usually used when there not much use of strategic and it mainly consists of two steps:

First write some code.

Fix problem in the code.

It can also be use with short system which does not require maintenance.

ADVANTAGES

No administrative overhead.

Useful for small projects.

DISADVANTAGES

No documentation

Errors are difficult to trace.

Impossible for large projects.

AGILE

In Agile modeling is an add-on to existing agile methodologies like Extreme programming (XP) and Rational Unified Process (RUP). In Agile modeling, continuous delivery of software, continuous collaboration with customer and continuous update according to the changes.

ADVANTAGES

Lightweight methods suit small-medium size project.

Produces good team cohesion

No overtime.

DISADVANTAGES

There is a lack of emphasis on necessary designing and documentation.

Needs experience and skill if not to degenerate into code-and-fix.

Programming pairs is costly.

EXTREME PROGRAMMING (XP)

Extreme programming is done in pairs and it is test driven development. In XP there is continuous planning, change, delivery. It is a kind of agile software development.

COMMERICAL OFF-THE-SHELF SOFTWARE (COTS)

In COTS using existing commercial software is made by adding some features to it. E.g. using database, spread sheets, word processors, etc.

ADVANTAGES

Fast, cheap solution.

Well defined project, easy to run.

May give all the basic functionality.

DISADVANTAGES

Limited functionality.

Licensing problem, freeware, shareware, etc.

A)

Importance of the following a procedural staged life cycle in a system investigation.

The importance of using the system development is the interactive process which consists of the following stages.

Preliminary investigation: One of the most time consuming task is to recognize the real problem of the pre-installed system. The analysis has to spend hours and days for understanding the fault in the system. In this stage the analyst makes a survey by the gathering all the available information needed for the system elements and allocation of the requirements to the software.

Analysis of the requirement: The analyst understands the working of the information and the functions of the software which is required for the system. The analyst makes a brief report of the requirements and tries to analyze the performance of the system which is to be developed.

System design: The analyst makes number of design of the system on the paper or on the computer and sees the rough image made of the system comprises of the all requirements or not. Once this is done analyst will select the best design.

System coding: The analyst translates the code or the programs in such a way that they become in machine readable form. The coding step is very time consuming and involves number of rooms for errors.

System testing: Once the analysis is through with the coding stage he tests the system and sees to it that it is working as per the expectations or not.

System implementation: This is one of the most vital phases as in this phase the analyst actually gives the system to the customer and expects for a positive feedback.

System maintenance: The last stage of the SDLC is that the analyst needs to maintain the system and see to it that it working within the standards set.

(1.2) B)

LEARNING OUTCOME #02

2.1 DISCUSS THE COMPONENTS OF FEASIBILITY REPORT AND WHEN TO USE THE FEASIBILITY STUDY

FEASIBILITY STUDY

Feasibility studies are for both users and the analysis. First, the study often presupposes that when the feasibility document is being made, the analyst is in a position to evaluate solution. Second most studies tend to over look the confusion inherent in system development the constraint and the assumed attitudes.

A feasibility study is conducted to select the best system that meets performance requirements. This entails an identification description an evaluation of candidate system, and the selection of the best system for the job.

In Feasibility study there are some fact-finding techniques they are:

Interviews

This is the most commonly used fact-finding technique. There are two types of interview: unstructured and structured. Open-ended question allow interviewee to respond in any way that seems appropriate. Closed-ended questions restrict answer to either specific choices or short, direct responses.

Observation

Effective technique for understanding system. This fact-finding is useful when validity of data collected is in question or when complexity of certain aspects of system prevents clear explanation by end-users.

Questionnaires

Special purpose documents that allow facts to be gathered from a large number of people while maintaining some control over their Reponses. There are two types of question, namely free-format and fixed format.

Focus group

Focus group is a technique where a group of people are asked about their perceptions, opinions, and attitudes towards a product, service, idea and etc. Questions are asked in an interactive group setting where participants are free to talk with other group member.

There are three types of Feasibility:

Economic Feasibility

Market Feasibility

Behavioral Feasibility

Economic Feasibility

Economic analysis is the most frequently used method for evaluating the effectiveness of a candidate system. More commonly known as cost/benefit analysis, the procedure is to determine the benefit and savings that are expected from a candidate system and compare them with costs.

Market Feasibility

FEASIBILTY REPORT

The culmination of the feasibility study is a feasibility report directed to management, it evaluate the impact of the proposed changes on the areas in question. The report is a formal document for management use brief enough and sufficiently nontechnical, yet detailed enough provide the basis for system design.

There is no standard format for preparing feasibility reports. Analysis usually decides on a format that suits the particular user and system.

2.2 IMPACT OF DIFFERENT FEASIBILTY CRITERIA ON A SYSTEM INVESTIGATION FOR GARMENT SHOP