10. Development of Life Cycle

8/7/2019 10. Development of Life Cycle

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Analysis & Design



A software development process provides abasis for organized production of software,using collection of predefined techniquesand notations.



Development Stagesy Sy stem conception

y Anal y sis

y Sy stem design

y

Class designy Implementation

y Testing

y Training

y Deplo y menty Maintenance



y S ystem conception:

Collect the application requirements.

y Analysisunderstand the requirements b y constructing

model. Understand the problem statement.

y S ystem Design

Design the architecture High level strateg y of the application.



y Class Design

Determine algorithm for implementation.

y ImplementationTranslate the design into programming code and

database structure.

y Testing

test the s y stem satisf y the requirements.

y Training

Help users to master the new application.



y Deployment

Place the application in the field.

y MaintenancePreserve the long term viabilit y of the application.

Entire process is seam less.



System conceptiony Sy stem anal y st have to know what the y want to create.

y Determine the need of the present market in this

stage.y Management involved in this stage and determine :

What the developers have to do and how it willimpact the market.

y A birds e y e view for software producty Evaluate feasibilit y and risk associated with the

project.



y Identif y the projects requirement and main features of proposed application.

y Development team visits the customer and their system.

y B y the investigation team writes a document that hold

the specification for the customer s y stem.



Analysisy Focus on creation of models.

y What must be done, not how it should be done

y Difficult task.y Anal y st must understand full y the s y stem.

y Sound models are prerequisites for an efficient,reliable , extensible and correct applications.

y Source of Information : Documents, Businessinterviews, related applications.



y Understand : nature of the s y stem, informationdomain, required functions, performance and

interfacing.y Based on above information s y stem engineer develops

a list of actors use cases and s y stem levelrequirements for the projects.

yR efine and update the list until user is satisfied.

Use case - describes "who" can do "what" withthe s y stem in question



1) Domain analysis

y Focus on real world things.

y E.g. Airplane flight real world object

y Flight reservation s y stem (application)y Domain objects are independent of an application.

y Meaningful to business experts. The y find b y eitherdomain anal y sis or b y prior knowledge.

y Focus on concepts and relationship

y Domain model -decide which information to captureand how to represent it.



y RQdoc, R TM contains complete descriptions of eachrequirement, including diagrams and references toexternal documents.



2) Application analysis

y Address the computer aspects of application & visibleto users.

yE.g. Flight reservation screen of flight reservations y stem

y Application object does not exist in the problemdomain

And meaningful to the context of the application.y Application model does not describe the

implementation.

y But how it appears from the outside



Design

y The design stage takes as its initial input therequirements identified in the approved requirementsdocument. For each requirement, a set of one or moredesign elements will be produced.



Design elements : the desired software features

y functional hierarch y diagrams,

y screen la y out diagrams,

y tables of business rules,

y business process diagrams,

y Pseudo code,y entit y -relationship diagram

y full data dictionar y .

y Skilled programmers ma y develop the software with

minimal additional input.



System designy Developer make strategic decisions.

y Choice of the architecture is based on requirements

as well as past experience.y Architecture high level plan for solving the

application problems.

y Interaction of the s y stem with other s y stem

y Architecture should support future modification.



Class designy Shifting from application concepts to computer

concepts.

ySelection of algorithm to implement major s y stemfunctions



Implementationy W riting actual code.

y Developer map design elements to programming

language and database code.y The outputs of the development stage include a full y

functional set of software

y that satisfies the requirements and design elements



Testingy After implementation, s y stem must be carefull y tested

before actual use.

y The s y stem is verified to check whether it meets thegiven business requirements.

y Uncover accidental bugs.

y Application should be tested on multiple hardwareand on different operating s y stem, if requires..

y Program should go with various test:

y Unit test:

y S ystem test:



Trainingy Train the users.

y A separate team prepare user documentation in

parallel for qualit y control.



Deploymenty Sy stem must work in field, on various platforms and in

various configuration.

y

Developers must tune the s y stem under various loads.



Maintenancey W hen s y stem is complete and has been deplo y ed, it

must be maintained for continued success.

yBugs remain in the s y stem will graduall y appear duringuse and must be fixed.



Development Life cycley Software Development Life Cycle (SDLC)

y SDL C is the process used b y people to develop or alter

the information s y stem.y Provide framework for planning and control the

creation of the s y stem.

y An y SDLC should result in to high qualit y s y stem that

meets the customer expectations and completes withinthe time.



SDLC modely W aterfall

y Iterative

y Spiraly R apid protot y ping

y Incremental



y W aterfall development

y Small to medium projects.

y Divide into six stages :y R elationship of each stage to others is like

waterfall.

y

During each stage, additional information isgathered, combined with the inputs and producethe stage deliverables.

y There is no back.



Iterative Development

y Incremental development slices the s y stemfunctionalities into increments.

y Develop the s y stem Anal y sis design implementation deliver working code

y Grow the scope of the s y stem [b y addingproperties and behavior to existing s y stem ]

y Each Iteration - ADIT



y Increments are for :

y Inception identifies work has to be done.

y

Elaboration deliver working architecture

y Construction fill the architecture with read y code

y Transition deliver the s y stem in operating environment



Devising System concepty System for :

Human relation department

Online auction system

y Some ways to find out new system concepts :y New Functionality

y Streamlining

y Simplification

y Automation

y Integration

y Analogies

y Globalization



Elaborating a Concepty W ho is the application for?

y W hat problems will it solve?

y W here will it be used?y W hen it is needed?

y W h y it is needed?

y How will it work?



ATMy A software through which customer can access Banks

computers and carr y out financial transaction withoutthe mediation of bank emplo y ee.



The ATM Case Studyy Preparing a problem statement : Design the

software to support a computerized banking

network including both human cashiers andautomatic teller machines to be shared b y aconsortium of banks. Each bank provides its owncomputer to maintain its own accounts and process

transactions against them. Cashier stations areowned b y individual banks and communicatedirectl y with their own banks computers HumanCashiers enter account and transaction data.

2010 B E II Sem IV CO 37



The ATM Case Studyy ATM communicate with a central computer that

clears transactions with the appropriate banks. An

ATM accepts a cash card, interacts with the user,communicates with the central s y stem to carr y outthe transaction, dispenses cash and prints receipts.The s y stem requires appropriate recordkeeping

and securit y provisions. The s y stem must handleconcurrent accesses to the same account correctl y .




The ATM Case Studyy The banks will provide their own software for their

own computers; y ou are to design the software for

the ATMs and the network. The cost of the shareds y stem will be apportioned to the banks accordingto the number of customers with cash cards.




ATM- Withdraw From CurrentName : W ithdraw From Current

Actor : ClientPre-conditions : User alread y logged-in

A menu is active with withdraw optionPost-conditions : Amount is deducted from users accountPurpose : To allow the client to withdraw mone y Description:

(1) Client initiates this usecase b y selecting withdraw(2) Sy stem get all the accounts (use case get Account)(3) Sy stem displa y s all the accounts and prompts to select an y one(3) Client selects one account(4) Sy stem prompts for the amount

(5) Client indicate an amount

(6) Sy stem issues mone y , update record, and confirms Alternative courses:

(3) & (4) Sy stem selects the onl y one available account(6) requested amount is bigger than balance, s y stem displa y message

Errors:

10. Development of Life Cycle

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