SDLC Models

Can anybody explain SDLC?
what is the diffecrence between waterfall model, rapid prototype model, agile model?
who will involve in gathering the information from the customer(initial stage of SDLC)?
How can we explain these models when interviewer asks?

[QUOTE=bharathi_ark;14265]Can anybody explain SDLC?

who will involve in gathering the information from the customer(initial stage of SDLC)?
[/QUOTE]

SDLC is software development life cycle.Which start even with an idea of new software(Requirement) and ends with maintenance phase.

Business Analyst involve in gathering the information from the customer..

SDCL is the software development life cycle. Its start with requirement phase in which SRS and BRS doc is collected corresponding Product and UA testing will go. Then its comes to design phase in which HLD document is collected corresponding Assembly testing wiil go. Then comes to detailed design & build phase in which FSD doc is collected and side by side componenet testing will go. At last Opertional testing will go in correspondes to deploy phase . This is the SDLC of V-model which company follows

How can we explain these models when interviewer asks?

HI,

1. [B]SDLC[/B] can be referred as Software Development Lifecycle or System Development Lifecycle. Which is used to plan the project activites with a chronological order in different phases like
a. Requirements Analysis
b. HLD(High-Level Design) and LLD(Low-Level Design)
c. Coding
d. Unit Testing
e. Testing
f. Maintenance

For more detail on SDLC you can browse net or can go thru Robert pressman's Sowftware Engineering Book.

2. Difference between [B]Water-Fall Model & Agile Model[/B] is bit logical.

In water-fall model the system or project is modeled in sequential manner. i.e the SDLC phases will be accomplished in linear fashion(one after the another). One activity can be started until the previous activity is completed.
[B]For ex:[/B] Testing can't be started until all previous phases are finished.

And when it comes to build delivery to testing until complete application is built it will not be released for testing.

This model is also termed as [B]Linear-Sequential Model.[/B]

The [B]Agile model[/B] to some extent is similar to Water-Fall Model, but in this; the application will be broken down in multiple chunks. All the SDLC phases will be done in chunks followed in multiple iterations.
[B]For ex:[/B] If application has 10 functionalities, the development will not be done for all completely and released to testing, instead the 1st functionality requirements will be analysed, designed, coded (and released for testing)tested and approved. Like this it can go for multiple iterations.

So the functionalities designed, coded and tested in such a way when they are intergrated there will be very less defects. The modules are developed and tested as plug and play components. This should be done effectively at design phase.

With this model you can achieve very good productivity. For ex: In future when you need to develop any similar application or same technology application you can reuse the developed and tested components as it is. Using this way your dev efforts and at the same time your testing efforts will be reduced. The reason is they are already tested and certified ones. At most you may get defects at the integration level not in functionality.

3. Business Analyst will be involved if available, if not it is development project manager who will be involved in capturing and documenting the requirments.

4. You need not explain the model in theoretical fashion, you can take your application and check what model it has used and explain how it was implemented.

Hope this answers your question.

Thanks
Narasimha Reddy

Dear Reddy:
Thanks for valuable info.

Hello everybody:
can anybody explain, the each phases of SDLC in detail.

Hi kureshi, here is the detailed explanation for the sdlc phases [b]system development life cycle[/b] the system development life cycle is the process of developing software systems through [b]investigation, requirement analysis, design(hld, lld), coding & debugging, and system maintenance(testing).[/b] the sdlc is also known as software systems development or application development. Below are the steps involved in the system development life cycle. Each phase within the overall cycle may be drilled of several steps. [b]software concept[/b] the first step is to identify a need for the new system. This will include determining whether a business problem or opportunity exists, conducting a feasibility study to determine if the proposed solution is cost effective, and developing a project plan. This process may involve end users who come up with an idea for improving their work or may only involve is people. Ideally, the process occurs in tandem with a review of the organization's strategic plan to ensure that it is being used to help the organization achieve its strategic objectives. Management may need to approve concept ideas before any money is budgeted for its development. [b] requirements analysis[/b] requirements analysis is the process of analyzing the information needs of the end users, the organizational environment, and any system presently being used, developing the functional requirements of a system that can meet the needs of the users. Also, the requirements should be recorded in a document, email, user interface storyboard, executable prototype, or some other form. The requirements documentation should be referred to throughout the rest of the system development process to ensure the developing project aligns with user needs and requirements. Is professionals must involve end users in this process to ensure that the new system will function adequately and meets their needs and expectations. [b] architectural design[/b] after the requirements have been determined, the necessary specifications for the hardware, software, people, and data resources, and the information products that will satisfy the functional requirements of the proposed system can be determined. The design will serve as a blueprint for the system and helps detect problems before these errors or problems are built into the final system. Is professionals create the system design, but must review their work with the users to ensure the design meets users' needs. [b]coding and debugging[/b] coding and debugging is the act of creating the final system. This step is done by is professionals. [b]system testing[/b] the system must be tested to evaluate its actual functionality in relation to expected or intended functionality. Some other issues to consider during this stage would be converting old data into the new system and training employees to use the new system. End users will be key in determining whether the developed system meets the intended requirements, and the extent to which the system is actually used. Hope this clears your question thanks
narasimha

see lest keep things in a simple way
in sdlc the phases are requirements specs followed by desingnig,coding,testing,production.
regards
anand

can any one please .... Explain why waterfall model is not recommended for large SOF projects

Waterfall model is easy for planning but difficult during defect fixing. It consumes more investement for dev team to bounce back and forth the box for every fixes and iteration in the testing.