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Software Architecture versus

Software Design

Suren K Poruri

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Problem statement

Architecture/Design are buzz words without

standard and consistent understanding in the

industry.

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Problem description

Multiple definitions

of architecture definitions/descriptions

Multiple architecture standards ( Togaf ,

4+1, etc.,)

Design means

class/object diagrams, sequence diagrams, etc., Is it really so?

No continuation

between architecture/design/codi

ng.

Architecture/design

created for process

compliance purpose

rather than solution purpose.

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Causes of the Problem

Project delays/cancellati

ons.

Cost of maintenance is high.

Communication overhea

d

Mismatch in

expectations

No consistency in

the artifacts

Benefits of

architecture not known

to business

. Why should they? Ex:

Building

Consumption

utilization

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The Need of Architecture ( Analogy 1)The Winchester “Mystery” House

38 years of construction – 147 builders 0 architects160 rooms – 40 bedrooms, 6 kitchens, 2 basements, 950 doors65 doors to blank walls, 13 staircases abandoned, 24 skylights in floorsNo architectural blueprint exists

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Construction Analogy 2

Can be built by one person

RequiresMinimal ArchitectureSimple processSimple tools

Architecting a house

Built most efficiently and timely by a team

RequiresArchitectureWell-defined processPower tools

Architecting a high rise

Can be built by multiple teams/partnersHeavy duty ArchitectureComplex processSophisticated costly tools

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Differences

Scale Process Cost Schedule Skills and development teams Materials and technologies Stakeholders Risks

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Architecture definition

Many definitions available at

cmu web site.

The essence is same• Architectu

re means structure and behavior of a system.

It includes • Horizontal ones

1) Process structure

• Vertical ones 2) Presentation structure 3) Logic structure 4) Data access structure

• 5) Datamodel/ Information structure.

Construction analogy –

pillars+ beams =

structure of the

building.

Process structureUI

structure

Logic structure

Data access structure

Data structu

re

1. Design is structure/behavior of a module.

Design definition

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Car analogy

SoftwareArchitect

ure

Modules

Modules

Modules

Modules

Interfaces

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Architecture scope

Navigation structure Page structure

Maintenance Transactions Report

Validation structure – consolidation of client side validations across the system Logging structure – What information need to be logged at a process level, layer level, module level Exception handling structure – System /process/layer level exceptions Use case/processs flow structure ( Presentation to business logic to data access layer) Identification of unique use case flows. Design patterns that we need to use? Deployment decisions Architectural style ( client/server, web , soa etc., ) Layering decision ( How many layers, responsibility of each layer, Layer interfaces etc., ) Business objects representation ( EJB, Pojo, etc., ) Database usage ( data repository only or data repository + business logic) Database access layer structure Security structure ( authentication, authorization, audit etc., )

TemplatePages

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Design Scope

Internal structure/behavior of each module Concrete UI pages design Algorithms design Class design based on SRP ( Single responsibility

principle)

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Architecture versus design

Architecture

System decisions

Hard to change

Scope - System

Design

Module decisions

Easy to change

Scope - module

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Here’s the Point!

If functionality is the only thing that matters, any software architecture will do!

Other things that really matter: design constraints quality attributes