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First Semester, 2013-2014 1SS ZG653 : Software Architecture Date : Thursday 25th July, 2013

BITSPilani

Pilani Campus

SS ZG653

Software Architecture

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Software Architecture

SS ZG653Lecture 1

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Course Details

Title: Software Architectures

Code: SSZG653

Faculty: PANKAJ VYAS

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Scope of the course

To understand architectural abstractions,

localizing and codifying the ways componentsinteract, and distinguish among the various

ways in which architectural principles can be

applied to software system and analysis anddesign.

To study about the role of architecture patterns

in software design To study about the applicability of design

patterns in software design

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Course Objectives

To illustrate the current state of the discipline of

Software Architecture and examine the ways in whicharchitectural design can affect software design

To explain the importance of nonfunctionalrequirements in terms of quality attributes of a system

To study the various architectural styles used in

software engineering To understand the evaluate designs of existing software

systems from an architectural perspective

To provide the intellectual building blocks for designing

new systems in principled ways, using well-understoodarchitectural paradigms

To present concrete examples of actual systemarchitectures that can serve as model for new designs

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Text Books

Len Bass, Software Architecture in Practice,

Pearson, Third Edition, ISBN 9789332502307

Buschmann, F. et al, Pattern Oriented

Software Architecture Volume1, Wiley, 1996.

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7/27First Semester, 2013-2014 7SS ZG653 : Software Architecture Date : Thursday 25th July, 2013

References

Mary Shaw & David Garlan, Software

Architecture Perspectives on an EmergingDiscipline, PHI, 1996.

Stephen T. Albin, The Art of Software

Architecture, Wiley Dreamtech, 2003.

Gamma, E. et. Al. Design Patterns: Elements of

Reusable Object Oriented Software, Addison

Wesley, 1995

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Thru the Semester

Lectures: 16 + 2 Review

Exams: 2 Midterm: 35%

Final: 50%

Quizzes: 15%

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Exams

Midterm Exam

Closed Book and notes

Final Exam

Open Book and notes

The exam solutions/answers are expected to

be of Masters Level with crisp, to-the-point,

concise, proper, neat and readable

presentation

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Lecture Wise Topics To be Covered

Lecture # Topics to be Covered

1 Understanding Software Architecture and its Importance2 Understanding the Various Quality Attributes (Only Introduction)

3 Understanding Availability , Interoperability and Modifiability

Attributes

4 Understanding Performance , Security and Testability Attributes

5 Understanding the role of various architecture tactics

6 Learning object-oriented basics and UML . Understanding classes,

objects, encapsulation, polymorphism, inheritance and their

representation in UML

7 UML class diagrams, sequence diagrams, class-responsibility-

collaboration cards (CRC cards)

8 Understanding the role of Architecture Patterns, Layered Architectural

style

Cont.

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ContLecture # Topics to be Covered

10 Architecture Pattern : Mud to structure category

(1) Blackboard (2) Pipe-and-Filter architectural styles

11 Architecture Pattern : Distributed System category

Broker Architecture style

12 Architecture Pattern : Interactive System Category

(1) Model-View-Controller (2) Presentation-Abstraction-Control

13 Architecture Pattern : Adaptable System Category

(1) Microkernel (2) Reflection

14 Role of Design Patterns in Software Design, Components of a typical

Design Pattern, Categories of Design Patterns, Understanding Iterators

15 Design Patterns : Behavioral Category

(1) Observer (2) Strategy (3) Command (4) Visitor

16 Design Patterns : Structural Category

(1) Adapter (2) Decorator (3) Composite (4) Proxy

17 Design Patterns : Creational Category

(1) Factory (2) Factory Method (3) Singleton

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Topic

Understanding Software

Architecture

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Software Architecture Definition

The software architecture of a program or computing

system is the structure or structures of the system,which comprise software elements, the externally

visible properties of those elements, and the

relationships among them(Ref: Bass, Clements and Kazman, Software Architecture in Practice, 2 nd edition)

Software Architecture is a description of the

subsystems and components of a software system

and the relationships between them. Architecture

thus attempts to define the structure the way inwhich something is constructed or organised

SWEBOK, 2004, Chapter 3 Software Design, Pg 3-3

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Software Architecture Definition

The software architecture of a program or computing

system is the structure or structures of the system,which comprise software elements, the externally

visible properties of those elements, and the

relationships among them(Ref: Bass, Clements and Kazman, Software Architecture in Practice, 2 nd edition)

Software Architecture is a description of the

subsystems and components of a software system

and the relationshipsbetween them. Architecture

thus attempts to define the structurethe way inwhich something is constructed or organised

SWEBOK, 2004, Chapter 3 Software Design, Pg 3-3

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A typical Software Architecture

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Whats clear?

System has 5 elements

Position of elements shows some properties.

Whats visible? Whats not visible? Layered?

Elements have a relationship

Is this complete architecture?

Is everything clear?

Is there anything missing?

Whats missing?

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Unclear from diagram

Nature of elements

Significance of separation

Contain process or programs or both

Runtime separation or division of labour

Clarity of the blocks; objects, tasks, functions,processes, distributed programs or something else

Responsibilities of each element

Their function; what do they do? How does their function relate to the system

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Unclear from Diagram

Significance of connections

Signify control or data, invoke each other,

synchronization

Mechanism of communications

Significance of layout Does level shown signify anything

Was the type of drawing due to space constraint

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Architecture Definition Implications

Architecture defines Software elements

Systems can and do comprise of more than

one structure

Every computing system with software has a

software architecture

The behaviour of each element is a part of the

architecture

The architecture of a system is a good one or a

bad one

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Some more views

Architecture

Is a high level design

Is the overall structure of the system

Is the structure of the components of a program

or system, their interrelationships, and theprinciples and guidelines governing their design

and evolution over time

Is components and connectors

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Patterns, Model and Reference Arch

An architectural pattern is a description of

element and relation types together with a setof constraints on how they may be used

A reference model is a division of functionality

together with data flow between the pieces A reference architecture of a reference model

mapped onto software elements (that

cooperatively implement the functionalitydefined in the reference model) and the data

flows between them

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Patterns, Model and Reference Arch

Reference models, architecture patterns and

reference architectures are not architectures;

they are useful concepts that capture

elements of an architecture

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Software Arch Importance

Communication among stake holders

Early design decisions

Transferable abstractions of a system

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Stake holder communication

Architecture provides a common language in which

different concerns can be expressed, negotiated andresolved

Customer, User, Project Manager, Development

Engineer, Test Engineer

On schedule and on budget: Customer

On schedule, on budget, work split among teams: Manager

Reliable, available, easy to use: User

Helps make early decisions Architectural analysis depends on communication

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First Semester 2013 2014 27SS ZG653 S ft A hit t D t Th d 25th J l 2013

Manifests earliest set of design decisions

The architecture

Defines constraints on implementation

Dictates organization structure

Inhibits or Enables a systems quality attributes

Enables predicting system qualities

Makes it easier to reason about and Manage

Change

Helps in evolutionary prototyping Enables more accurate cost and schedule

estimates

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