Asst.Prof. Dr. Surasak Mungsing

The role of softwareThe role of softwareOur civilization runs on software

Innovation to capture new valueImproving productivity of resources deployed

The privilege and responsibility of the software professional

Number of software professional worldwideNumber of software professional worldwide

Number of IT professionals worldwide

y = -128.47x3 + 12800x2 - 59294x + 146623

0

2,000,000

4,000,000

6,000,000

8,000,000

10,000,000

12,000,000

14,000,000

16,000,000

Number of IT professionals worldwide(assumptions)

Poly. (Number of IT professionalsworldwide (assumptions))

(Source: Grady Booch, IBM Fellow)

SLOC/developer/yearSLOC/developer/yearNew or modified source lines of code per year per developer

y = -0.0328x3 + 4.8392x2 - 67.596x + 1062.8

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

1945

1947

1949

1951

1953

1955

1957

1959

1961

1963

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

New or modified source lines of code per year( per developer)assumptions

Poly. (New or modified source lines of code per(( year per developer)assumptions

(Source: Grady Booch, IBM Fellow)

New or modified SLOC/year and cumulativeNew or modified SLOC/year and cumulativeNew or modified source lines of code per year per developer & cumulative

0

100,000,000,000

200,000,000,000

300,000,000,000

400,000,000,000

500,000,000,000

600,000,000,000

700,000,000,000

800,000,000,000

New or modified source lines of code peryear

Cumulative source lines of code

(Source: Grady Booch, IBM Fellow)

Dimensions of software complexityDimensions of software complexityHigher technical complexity - Embedded, real-time, distributed, fault-tolerant - Custom, unprecedented, architecture reengineering - High performance

Lower technical complexity - Mostly 4GL, or component-based - Application reengineering - Interactive performance

Highermanagement complexity - Large scale - Contractual - Many stake holders - “Projects”

Lowermanagement complexity - Small scale - Informal - Single stakeholder - “Products”

Defense MIS System

Defense Weapon SystemTelecom

Switch

CASE Tool

National Air TrafficControl System

Enterprise IS(Family of ISApplications)

CommercialCompiler

BusinessSpreadsheet

IS ApplicationDistributed Objects

(Order Entry)

Small ScientificSimulation

Large-ScaleOrganization/Entity

Simulation

An average software project - 5-10 people - 3-9 month duration - 3-5 external interfaces - Some unknowns & risks

EmbeddedAutomotive

Software

IS ApplicationGUI/RDB

(Order Entry)

(Source: Grady Booch, IBM Fellow)

Creating the illusion of simplicityCreating the illusion of simplicity

(Source: Grady Booch, IBM Fellow)

Architecting a dog house Architecting a dog house

Can be built by one personRequires

Minimal modelingSimple processSimple tools

Kruchten

Architecting a house

Built most efficiently and timely by a teamRequires

ModelingWell-defined processPower tools

Kruchten

Architecting a high riseArchitecting a high rise

DDifferencesifferencesScaleProcessCostScheduleSkills and development teamsMaterials and technologiesStakeholders Risks

Architecture is EarlyArchitecture is EarlyArchitecture represents the set of earliest

design decisionsHardest to changeMost critical to get right

Architecture is the first design artifact where a system’s quality attributes are addressed

Architecture DrivesArchitecture DrivesArchitecture serves as the blueprint for the

system but also the project:Team structureDocumentation organizationWork breakdown structureScheduling, planning, budgetingUnit testing, integration

Architecture establishes the communication and coordination mechanisms among components

Software ArchitectureSoftware ArchitectureSoftware architecture is what software architects

doAnother GoSoftware architecture encompasses the set of

significant decisions about the organization of a software systemSelection of the structural elements and their interfaces by

which a system is composedBehavior as specified in collaborations among those elementsComposition of these structural and behavioral elements into

larger subsystemsArchitectural style that guides this organization

Beck

Formal DefinitionIEEE 1471-2000

Software architecture is the fundamental organization of a system, embodied in its components, their relationships to each other and the environment, and the principles governing its design and evolution

IEEE 1471-2000

Software Architecture DefinitionSoftware Architecture DefinitionDefinition

A software system’s architecture is the set of principal design decisions about the system.

Software architecture is the blueprint for a software system’s construction and evolution.

Design decisions encompass every aspect of the system under development. This includes design decisions related to Structure Behavior Interaction Non-functional properties

Other Definitions of Software ArchitectureOther Definitions of Software Architecture

Perry and WolfSoftware Architecture = { Elements, Form, Rationale }

what how whyShaw and Garlan

Software architecture [is a level of design that] involves the description of elements from which systems are built, interactions among those elements, patterns that guide their composition, and constraints on these patterns.

KruchtenSoftware architecture deals with the design and

implementation of the high-level structure of software.Architecture deals with abstraction, decomposition,

composition, style, and aesthetics.

Prescriptive vs. Descriptive ArchitecturePrescriptive vs. Descriptive Architecture A system’s prescriptive architecture captures

the design decisions made prior to the system’s construction. It is the as-designed or as-intended architecture.

A system’s descriptive architecture describes how the system has been built. It is the as-implemented or as-realized architecture.

“… about the structure of the system”

Why prescriptive architecture?Why prescriptive architecture?Act as the set of rules by which all

stakeholders have to play“rules of the road” for various projects within

organization to align well with business goalsAct as the technology product blueprint

for intranet application: list of products to buyReduces deployment risk for organization

tried and tested models“…architecture is about principles and

guidelines”

Architectural EvolutionArchitectural Evolution When a system evolves, ideally its prescriptive

architecture is modified first. Unfortunately often the system and thus its

descriptive architecture is often directly modified.

This failure of update happens because of Developer sloppiness Perception of short deadlines which prevent thinking

through and documenting Lack of documented prescriptive architecture Need or desire for code optimizations Inadequate techniques or tool support

Architectural Drift and Architectural ErosionArchitectural Drift and Architectural Erosion

Definition. Architectural drift involves architectural design decisions that are applied directly to a system’s descriptive architecture, but are not properly reflected in the system’s prescriptive architecture.

Leads to inadaptability; results in lack of coherence

Definition. Architectural erosion involves architectural design decisions that are applied directly to a system’s descriptive architecture, and that violate design decisions captured by the system’s prescriptive architecture. E.g., “load bearing walls”

Leads to disastrous results

Architectural RecoveryArchitectural Recovery

If drift or erosion are allowed to occur, the development organization is likely to be forced to recover the system’s architecture sooner or later.

Definition. Architectural recovery is the process of determining a software system’s architecture from its implementation-level artifacts.

Implementation-level artifacts can be Source code Executable files Java .class files

DeploymentDeployment

A software system cannot fulfill its purpose until it is deployed, that is, until its executable modules are physically placed on the hardware devices on which they are supposed to run.

The deployment view of an architecture can be critical in assessing whether the system will be able to satisfy its requirements.

Possible assessment dimensions Sufficient memory Power consumption Available and required bandwidth

A System’s Deployment Architecture ModelA System’s Deployment Architecture Model

Software Architecture’s ElementsSoftware Architecture’s Elements

A software system’s architecture typically is not (and should not be) a uniform monolith.

A software system’s architecture should be a composition and interplay of different elements

Processing Data, also referred as information or state Interaction

ComponentComponent

Elements that encapsulate processing and data in a system’s architecture are referred to as software components.

Definition. A software component is an architectural building block that encapsulates a subset of the system’s functionality and/or data, and restricts access to them via an explicitly defined interface.

ConnectorConnector

In complex systems interaction might become more important and challenging than the functionality of the individual components.

Definition. A software connector is an architectural building block tasked with regulating interactions among components.

In traditional, desktop software systems, connectors would have usually manifested themselves as simple procedure calls or shared data accesses.

Connector ExamplesConnector Examples Connector Examples

Procedure call connectors Shared memory connectors Message passing connectors Streaming connectors (e.g.. stream music from

devices) Distribution connectors (distribute s/w to

clients) Wrapper connectors (data, object wrapper)

Components provide application-specific services.

Connectors are application-independent.

ConfigurationConfiguration

Components and connectors are composed in a specific way in a given system’s architecture to accomplish that system’s objective.

Definition. Architectural configurations, or topologies, capture architectural structure via graphs whose nodes represent components and connectors, and whose edges represent their interconnectivity that describes architectural structure.

An Example ConfigurationAn Example Configuration

Architectural StyleArchitectural Style Observation

Certain design choices regularly result in solutions with superior properties.

Compared to other possible alternatives, solutions such as this are more elegant, effective, efficient, dependable, evolvable, scalable, and so on.

Definition. An architectural style is a named collection of architectural design decisions that

are applicable in a given development context constrain architectural design decisions that are

specific to a particular system within that context elicit beneficial qualities in each resulting system.

Architectural PatternArchitectural Pattern

Definition. An architectural pattern is a set of architectural design decisions that are applicable to a recurring design problem, and parameterized to account for different software development contexts in which that problem appears.

An example pattern that is used widely in modern distributed systems is the three-tiered system pattern.

Three-tiered system applications science, banking, e-commerce, reservation

systems

Three-tiered architectural patternThree-tiered architectural pattern

Front Tier: functionality to access the system’s services

Middle Tier: contains the application’s major functionality

Back Tier: contains the application’s data access and storage functionality.

Architectural Models, Views, and VisualizationsArchitectural Models, Views, and Visualizations Architecture Model

An artifact documenting some or all of the architectural design decisions about a system (structural, process, interface, and deployment)

Architecture Visualization A way of depicting some or all of the

architectural design decisions about a system to a stakeholder. E.g. Structure101

Architecture View A set of elements and the relations among them;

module, components and connectors, allocation view.

Architectural ProcessesArchitectural Processes

Architectural Analysis encompasses activities such as:

Determining whether the set of design decisions comprising an architecture are consistent

Determining whether an implemented system conforms to the set of design decisions in the architecture

Architectural Evolution: The process of modifying the architectural

design decisions for a system.

Scope of Software ArchitectureScope of Software ArchitectureEvery system has an architectureDetails of the architecture are a reflection of

system requirements and trade-offs made to satisfy them

Possible decision factorsPerformanceCompatibility with legacy softwarePlanning for reuseDistribution profile

Current and futureSafety, security, fault tolerance requirementsEvolvability needs

Changes to processing algorithms Changes to data representation Modifications to the structure/functionality

What Makes a “Good” Architecture?What Makes a “Good” Architecture?Process observations:

Product of architect(s)List of quality attributes and functional

requirementsArchitecture is well-documentedCirculated to stakeholdersAnalyzed for quantitative measure and evaluate

for quality attributesResults in a specific set of resource contention

areas (e.g. network utilization)

Product observations:Well-defined modules with well-defined

interfaceAchieve quality attributes using architectural

strategyShould not depend on particular version of a

commercial productAllows modifiabilityFeature well-defined processes or tasks

What Makes a “Good” Architecture?What Makes a “Good” Architecture?

Why is SA Important?Communication among stakeholdersEarly design decisionsTransferable abstraction of a system

Every interesting software-intensive system has an architecture

The most successful software architectures are intentional, manifest, and visible - and beautiful

SummarySummary

Q & AQ & A

Commercial Software ArchitectureCommercial Software Architecture

Commercial softwareCommercial softwareless commonly, payware, is computer

software that is produced for sale or that serves commercial purposes.

is most often proprietary software, but free software packages may also be commercial software

All or parts of software packages and services that support commerce are increasingly made available as free software

Commercial off-the-shelf

Selecting off-the shelf componentsSelecting off-the shelf componentsThe high-level selection process begins with the practice of

locating candidates.

Selecting off-the-shelf components that fit well together in a new system requires evaluating each candidate off-the-shelf component to ensure the component not only meets functional and quality requirements but also is compatible with other components in the system.

Application integrators manage processes and knowledge to ensure successful component selection, component integration, and component maintenance.

For systems designed using off-the-shelf component types, with known cost, reliability, and weight, system design and component selection becomes a combinatorial optimization problem.

ERPERP

Enterprise resource planning (ERP) integrates internal and external management information across an entire organization, embracing finance/accounting, manufacturing, sales and service, customer relationship management, etc. ERP systems automate this activity with an integrated software application. Its purpose is to facilitate the flow of information between all business functions inside the boundaries of the organization and manage the connections to outside stakeholders.[

SAP SolutionsSAP Solutions

SAP System ArchitectureSAP System ArchitectureDivide into three layers, which make up the basic services of a business application system:

Presentation layer enables the user to interact with the relevant application

Applications are executed in the application layer

Data to be processed is managed by the database layer

SAP R/3 : Basis SystemSAP R/3 : Basis System

SAP R/3 ในส่�วนของ Basis (คำ��ว�� Basis

ในระบบ SAP ก็�คำ�อส่�วน System

Administration ในระบบ SAP R/3 ) ส่��งแรก็ที่��ต้�องร� �คำ�อ SID ของระบบ SAP ซึ่��งใน SID

ของระบบ SAP R/3 จะประก็อบไปด้�วย 3 ส่�วน ส่�วนแรก็ คำ�อ Presentation Server ซึ่��ง

ก็�คำ�อในส่�วนของหน��จอ GUI

ส่�วนที่��ส่องคำ�อ Application Server

หร�อส่�วนของ SAP R/3 Instance ส่�วนน�#คำ�อ Kernel ในระบบ SAP เป%นส่�วนที่��ที่��ง�นในด้��น Application Logic ของโปรแก็รม ABAP

ส่�วนส่(ด้ที่��ยคำ�อ Database Server ซึ่��งเป%นส่�วนที่��เก็�บข�อม�ลที่*#งหมด้ในระบบ SAP R/3

Architecture of the SAP Web Application ServerArchitecture of the SAP Web Application Server

Installation Options

• SAP Web Application Server ABAP System. In the graphic these are the components in the yellow box on the left.• SAP Web Application Server Java System. In the graphic these are the components in the green box on the right.• SAP Web Application Server ABAP+Java System. These are all the components of the graphic.

Q&AQ&A