Software Maintenance.pptx

7/30/2019 Software Maintenance.pptx

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Software Maintenance


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Importance of Software

Maintenance

Amount

70% of Cost

Forms :

recovery

bug fixes

enhancements


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Taxonomy of Software

Maintenance activities

Adaptive

Corrective

Perfective

Preventive


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ADAPTIVE: Adapt the SW to

another

environment

New SW/HW

paradigm OS

Platform

REASONS:

market-driven

technology_driven

For:

long term

SW evolution Market

penetration


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Corrective Maintenance

Diagnose reportedSW errors

By:

testers beforedelivery

client during use

maintenance team

Maybe :

unscheduledcostly

imperfectdebugging


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types

Specification

missing req

incorrect

incomplete

Design

poor

algo

data structure

HLD style

Code

incorrectmapping todesign

easy to fix


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Perfective Maintenance

Improvement functional

nonfunctional

e.g.

modify interfaces

improve usability

enhanceresponse time

reduce memoryreq

Initiated by: external users

productmanagers

revision evolution

Requires modification

of specs

design

code


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Preventive

To improve futuremaintainability

Reducepossibilities ofmore errors

Reducemaintenance cost

Forms

SWrestructuring

change inALGO

enhancementof SW

documentation

This is called

REVERSE


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Stats

75% adaptive and perfective

20 % corrective

5 % preventive


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SW Maintenance Process

1. Phase I : Identification

2. Phase 2: Analysis


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Phase I : Identification

problem,

modification,

classification,prioriti

zation

Validation

Resource

allocation

SW change

request(SCR)Schedule

maintenance


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Phase 2: Analysis

Economic

Technical

Prepare prototype

Risk analysis

Determine

Impact of changesAlternative

solutions


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Phase 3: Design

Outline action plan

Identify affected

modules

Modification ofmodules

Develop test cases

for unit and

regression test

Review test plans


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Phase 4

Implement

Perform

changes

to code Do code review

walkthrough

checklist

Integrate

review if

changes

reflect designchanges


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Phase 5 : Testing

Regression test

ensure that

changes do not

affect other

related SW

features

System test

ensure that

modifications are

successfully

incorporated

Do acceptancetesting


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Phase 6: AcceptanceTest

Acceptance testing

documents

code

Done at developer or

client premises or

both


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Phase 7 : Delivery

Delivery

Approval of SW

developer

client

representatives


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SW mgt techniques

Reverse

engineering

Extraction

decipher digital HWcomponent

discover

functional specs

deconstruction of

SW

Design recovery

by moving from

SW appropriate

documentationmaybe obtained


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SW mgt techniques

Restructuring

Change in current

software

configurationChange in control

structure used

Module

interrelationships

For more

reusability

Reengineering

Renovation or

Rejuvenation

Forward SWengineering

Add Requirements

that are not met

Software Maintenance.pptx

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