History Of The System Development Life Cycle

Published Date: 02 Nov 2017

SDLC stands for System Development Life Cycle SDLC is a process used by IT analysts in order to develop or redesign high quality software system which meets both the customer and the real world requirement taking into consideration all associated aspects of pros and cons of software testing, analysis and post process maintenance.

SDLC MODEl explain

Different life cycle models

Spiral model

Spiral was introduced by Boehm. It is a model used in high risk software development projects and it is used in Large, expensive or complicated projects.In spiral model we can determine objectives, alternatives and constraints and also we can analysis risk and evaluate alternatives.

Spiral model is also called the Meta type model because both waterfall and prototype models are used in it. Spiral model is a systematic development over the loops which enable at the same time to make a prototype and show it to the clients after completion of various phases.

Advantages of spiral model

Spiral model is the most flexible SDLC model.

Project monitoring is very easy and effective.

In spiral model risk management is one of the in-built features of the model.

In spiral model changes can made later easily if need any.

Project cost, schedule becomes more and more realistic as project move forward and loops in spiral gets completed.

Spiral model is most suitable for high risk projects.

Using spiral model high customized products can be developed.

Disadvantages of spiral model

High cost is incurred.

Spiral model is complicated with project with clear SRS.

Skills required, evaluating and reviewing project from time to time, need expertise.

Rules and protocols should be followed properly to effectively implement this model. Doing so, through-out the span of project is tough.

Due to various customizations allowed from the client, using the same prototype in other projects, in future, is difficult.

It is not suitable for low risk projects.

Meeting budgetary and scheduling requirements is tough if this development process is followed.

Amount of documentation required in intermediate stages makes management of project very complex affair.

Waterfall model

First impression brought by Dr.Winston W. Royce in 1970.It is a traditional model.It has linear sequential flow, which one stage comes after completing previous one.

Advantages in waterfall model

It is easy to use and it is understandable.

Phases are completed one by one.

Waterfall model work well on smaller projects.

Disadvantages in waterfall model.

High amount of risk and uncertainty.

Not suitable for complex and object oriented projects.

Once the application is in testing stage it is hard to go back and make any changes.

Prototype cannot be given until the stages are over.

RAD(Rapid Application Development)

It is type of incremental model. Components of functions are in parallel as if they are mini projects.

Phases in RAD

Business modelling.

Data modelling.

Process modelling.

Application generation.

Testing and turnover.

Advantages of RAD

Reduce development time.

Increase reusability of components.

Quick initial reviews.

Encourage customer feedback.

Integration from very beginning solves a lot of integrations issues.

Disadvantages of RAD

Cannot be used in small project

Need modelling skill and it’s highly dependence

Code generating is very high

Need a strong

Agile model

Development of agile was led by Scott Amber and it is used for software based system, it is an adaptive system with more flexibility than traditional methods. Agile describes how to approach modeling and documentation and it has willingness for motion, liveliness, activity, agility in motion .Agile methods generally promote a disciplined project management process

Advantages of agile model

Promotes:

adaptive planning,

evolutionary development and delivery

time-boxed iterative approach

encourages rapid and flexible response to change

Conceptual framework that promotes foreseen interactions throughout the development cycle

Agile methods break tasks into small increments with minimal planning and do not directly involve long-term planning

Cost effectiveness

It defines explicit techniques for agile projects

To improve modeling and documentation on prescriptive processes.

Disadvantages of Agile.

Effort estimation will be tough at the beginning of the software development

Less importance for designing and documentation

Agile requirement are barely sufficient

Testing is integrated throughout the life cycle

Project will be mess for designing and documentation

Relentlessness of iteration can be mentally quit tiring

Poor documentation

Experience resource will be needed

Context diagram

Level 0 DFD

Level 1 DFD

Fact finding methods

Question asked from the manager

1. Who are the responsible personals for handling the sales/orders of customers?

• Salesman

• Department Manager

• Assistant Manager

2. How the customer requirements are recorded?

3. Who is authorized for handling the money measures of the customers when an order is placed?

4. If so how do you record those details? (Please Specify)

5. How is the current customer registration managed?

6. How do you show the prototype models of boat to customers?

7. If an order is placed, how is the order given to other department and the warehouse?

8. How is the current operations taken place?

9. Are you satisfied with the manual system? If not please specify the reasons.

10. What are the facilities you expect from the system which is to be introduced?

Questionnaires for the Salesman

1. What are the operations carried out by you?

2. How are the Payments of the customers maintained?

3. Is there an installment method?

I. Yes ____

II. No ____

4. Are you satisfied with the current manual system?

I. Yes _____

II. No _____

5. If no please high light the reasons why are the dislike of the current system?

6. What are the features you expect from a new computerized system?

7. Does the data get lost while recording them manually?

I. Yes _____

II. No _____

8. If yes how do you recover the details back again?

Questionnaires for the Customers

1. What are the problems faced when ordering a product?

2. Are you satisfied with the current services given to you with the manual system?

I. Yes _____

II. No _____

3. Is there any other problem or difficulty faced during this process? Please Specify.