SDLC

Software Development Life Cycle

Software Development Life Cycle (SDLC):
       
       I)  Requirements Gathering (BA/BT)

in case of cusomer specific application:
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Business Analyst category people gathers requirements from the customer, and prepares
BRS (Business Requirement specification) and submits to Project Manager.

PM sends BRS for review, after getting review report and clarifications, PM approve the document.

Document stages:

a)document creation/preparation

b)document review

c)document approval

Baselined document (finalised)
------------------

we can execute this baselined document

in case of Software Product:
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Business Team  gathers requirements from model cusomers and explores compititer products, and prepares
PRD (Product Requirement Document) and submits to Project Manager.

PM sends PRD for review, after getting review report and clarifications, PM approve the document.

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Output of this stage:
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Baselined BRS/PRD

Document names may vary from one company to another

Ex: BRS/CRS/BRD/URS/PRD etc..
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        II) Analysis & Planning (Tech Manager and Project Manager)
        ------------------------------------------------------
Technical Manager analyzes BRS document interms of below factors

a) are they compleate requirements?

b) are they correct requirements?

c) are they achivable requirements?

d) are they Testble requirements?

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after analyzing the above factors Technical Manager creates SRS (Software Requirements specification) Document

SRS consists of two sub documens

    a) FRS (functional requirement specification)

FRS describes functionalities to be developed

    b) SRS (System Requirements specification)

SRS describes Software & Hardwsre to be used
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During SRS creation TM concentrates on Technology selection

He considers below factors for selecting Technology:

Technical factors:
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a) Nature of the Application

b) Organization's experience
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Busines factors:
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a) Cost/Budjet

b) Customer intrests

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Planning:
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Project manager analyzes risks, creates project plan, team formation etc...

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Output:
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SRS
Project Plan



        III) Design (System Arch)
        --------------------
Input: SRS
------
System Archtech / senior developer creates Software Design document(SDD)

It consists of two types of design docs

    a) HLD (High Level Design) or Global Design

Overal archtechure of the system

    b) LLDs (Low Level design) or Detailed Design
Internal archtechure of each and every Unit/component/module

Note: System Archtech uses either word document or UML like tools for Software


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Output:
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SDD

        Implimentation/Coding (Developers/programmers)
        ----------------------------------------------
Input:
SDD

Developer/Programmers develop the code based on Design documents and they follow
coding standards

Output:
-------
Code documents
softwere (.exe file)       

        Testing (Testers)
        -----------------
Input:
------
softwere (.exe file)
SRS

Testers test software based on SRS, if they find any mismatch, send defect reports
, after fixing defects, confirm fixes and close defects   


Output:
-------
Tested software
Test documens    

   
        Release & Maintenance (Release Team/Maintenance Team)
        -----------------------------------------------------
Release:
--------
PM forms Release Team, Release team consists of a few developers, testers,project managene executive, and system administrator

Release Team goes to customer place and deploys software.

Release Team provides some training to the customer site people (if required)

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Maintanense:
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PM forms Maintanense Team, Maintanense team consists of a few developers, testers, and project managene executive

Release Team recieves customer change requests and perform required changes

Maintanense (3 types)
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a) Modifications
    i) Corrective changes
    ii) Enhancements

b) Migration
Migrating from old technology to new technogy

(ex: windows 98 to Vista/windows 7)
Ms Access to SQL Server/Oracle)

c) Retirement
Retiring the Old system and developing New system