INFORMATION SYSTEMS @ X INFO425: Systems Design Chapter 9 Moving to Design Part 2.
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Transcript of INFORMATION SYSTEMS @ X INFO425: Systems Design Chapter 9 Moving to Design Part 2.
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
INFO425: Systems DesignINFO425: Systems Design
Chapter 9Chapter 9
Moving to DesignMoving to Design
Part 2Part 2
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Design and Integrate the NetworkDesign and Integrate the Network
Network specialists establish network based on Network specialists establish network based on strategic planstrategic plan
Project team typically integrates system into Project team typically integrates system into existing networkexisting network
Technical requirements have to do with Technical requirements have to do with communication via networkscommunication via networks
Technical issues handled by network specialistsTechnical issues handled by network specialists
Reliability, security, throughput, synchronizationReliability, security, throughput, synchronization
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Network DesignNetwork Design
Integrate network needs of new system into existing Integrate network needs of new system into existing network infrastructurenetwork infrastructure
Describe processing activity and network connectivity Describe processing activity and network connectivity at each system locationat each system location
Describe communications protocols and middleware Describe communications protocols and middleware that connects layersthat connects layers
Ensure that network capacity is sufficient Ensure that network capacity is sufficient Data size per access type and average Data size per access type and average Peak number of access per minute or hourPeak number of access per minute or hour
INFO425: Systems DesignINFO425: Systems Design
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Network Diagram for RMO Network Diagram for RMO Customer Support System Customer Support System (Figure 9-14)(Figure 9-14)
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Design the Application ArchitectureDesign the Application Architecture
Specify how system use cases are carried outSpecify how system use cases are carried out
Described during system analysis as logical models of Described during system analysis as logical models of system activitiessystem activities
After design alternative is selected, detailed computer After design alternative is selected, detailed computer processing is designed as physical models, such as processing is designed as physical models, such as physical data flow diagrams and structure charts physical data flow diagrams and structure charts (traditional) or interaction diagrams and class diagrams (traditional) or interaction diagrams and class diagrams (OO)(OO)
Approach varies depending on development and Approach varies depending on development and deployment environmentsdeployment environments
INFO425: Systems DesignINFO425: Systems Design
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Design the User InterfacesDesign the User Interfaces
User interface quality is critical aspect of systemUser interface quality is critical aspect of system
Design of user interface defines how user interacts Design of user interface defines how user interacts with systemwith system
GUI GUI –– windows, dialog boxes, mouse interaction windows, dialog boxes, mouse interaction
Sound, video, voice commandsSound, video, voice commands
To user of system, user interface is the systemTo user of system, user interface is the system
User interface specialistsUser interface specialists –– interface designers, interface designers, usability consultants, human factors engineersusability consultants, human factors engineers
INFO425: Systems DesignINFO425: Systems Design
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Design the System InterfacesDesign the System Interfaces
System interfaces enable systems to share and System interfaces enable systems to share and exchange informationexchange information
Internal organization systemsInternal organization systems Interfaces with systems outside organizationInterfaces with systems outside organization New system interfaces with package application that organization New system interfaces with package application that organization
has purchased and installedhas purchased and installed
System interfaces can be complexSystem interfaces can be complex Organization needs very specialized technical skills to Organization needs very specialized technical skills to
work on these interfaceswork on these interfaces
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Design and Integrate the DatabaseDesign and Integrate the Database
System analysis data model used to create System analysis data model used to create physical database model physical database model
Collection of traditional computer files, relational Collection of traditional computer files, relational databases, and/or object-oriented databasesdatabases, and/or object-oriented databases
Technical requirements, such as response times, Technical requirements, such as response times, determine database performance needsdetermine database performance needs
Design work might involveDesign work might involve Performance tuning, indexingPerformance tuning, indexing NormalizationNormalization Integration between new and existing databasesIntegration between new and existing databases Choosing data access strategy (e.g., static vs. dynamic Choosing data access strategy (e.g., static vs. dynamic
embedded SQL)embedded SQL) Recovery from failure (RAID, mirroring, etc.)Recovery from failure (RAID, mirroring, etc.)
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Design and Integrate the System ControlsDesign and Integrate the System Controls
Final design activity to ensure system has Final design activity to ensure system has adequate safeguards (system controls) to protect adequate safeguards (system controls) to protect organizational assetsorganizational assets
Controls are needed for all other design activitiesControls are needed for all other design activities User interface – limit access to authorized usersUser interface – limit access to authorized users System interface – protect from other systemsSystem interface – protect from other systems Application architecture – record transactionsApplication architecture – record transactions Database – protect from software/hardware failureDatabase – protect from software/hardware failure Network design – protect communicationsNetwork design – protect communications
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Deployment EnvironmentDeployment Environment
Deployment environment definition bridges analysis and Deployment environment definition bridges analysis and designdesign
HardwareHardware System softwareSystem software Networking Networking
Common deployment environments in which system will Common deployment environments in which system will operateoperate
Related design patterns and architectures for Related design patterns and architectures for application softwareapplication software
Hardware / System Software decisions made in tandem, Hardware / System Software decisions made in tandem, usuallyusually
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Single-Computer and Multitier ArchitectureSingle-Computer and Multitier Architecture
Single-computer architectureSingle-computer architecture Mainframe-basedMainframe-based Limited by single machine capacityLimited by single machine capacity
Clustered and multi-computer architectureClustered and multi-computer architecture Group of computers to provide processing and data storage Group of computers to provide processing and data storage
capacitycapacity Cluster acts as a single systemCluster acts as a single system Multicomputer hardware/OS can be less similar than Multicomputer hardware/OS can be less similar than
clusteredclustered
INFO425: Systems DesignINFO425: Systems Design
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Centralized and Distributed ArchitectureCentralized and Distributed Architecture
Distributes system across several computers and Distributes system across several computers and locationslocations
Relies on communication networks for geographic Relies on communication networks for geographic connectivityconnectivity
Client/server architecture dominant model for Client/server architecture dominant model for distributed computingdistributed computing
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Computer NetworkComputer Network
Set of transmission lines, specialized hardware, Set of transmission lines, specialized hardware, and communication protocolsand communication protocols
Enables communication among different users and Enables communication among different users and computer systemscomputer systems
Local area network (LAN)Local area network (LAN) less than one kilometer less than one kilometer long – connects computers within single buildinglong – connects computers within single building
Wide area network (WAN)Wide area network (WAN) over one kilometer long over one kilometer long – implies much greater, global, distances– implies much greater, global, distances
RouterRouter – directs information within network – directs information within network
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
The Internet, Intranets, and ExtranetsThe Internet, Intranets, and Extranets
InternetInternet – global collection of networks that use – global collection of networks that use TCP/IP networking protocolsTCP/IP networking protocols
IntranetsIntranets Private networks using same TCP/IP protocols as the InternetPrivate networks using same TCP/IP protocols as the Internet Limited to internal users Limited to internal users
ExtranetsExtranets Intranets that have been extended outside the organizationIntranets that have been extended outside the organization
INFO425: Systems DesignINFO425: Systems Design
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Application ArchitectureApplication Architecture
Complex hardware/networks require more complex Complex hardware/networks require more complex software architecturessoftware architectures
There are commonly used approaches (patterns) There are commonly used approaches (patterns) for application architecturefor application architecture
Client/server architectureClient/server architecture
Three-layer client/server architectureThree-layer client/server architecture
Web services architectureWeb services architecture
Internet and Web-based application architectureInternet and Web-based application architecture
INFO425: Systems DesignINFO425: Systems Design
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Client/Server ArchitectureClient/Server Architecture
Client/server divides programs into two typesClient/server divides programs into two types ServerServer – manages information system resources or – manages information system resources or
provides well-defined services for clientprovides well-defined services for client ClientClient – communicates with server to request resources – communicates with server to request resources
or servicesor services Advantage – deployment flexibilityAdvantage – deployment flexibility
Location, scalability, maintainabilityLocation, scalability, maintainability
Disadvantage – complexity Disadvantage – complexity Performance, security, and reliabilityPerformance, security, and reliability
INFO425: Systems DesignINFO425: Systems Design
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Three-Layer Client/Server ArchitectureThree-Layer Client/Server Architecture
Layers can reside on one processor or be Layers can reside on one processor or be distributed to multiple processorsdistributed to multiple processors
Data layerData layer – manages access to stored data in – manages access to stored data in databasesdatabases
Business logic layerBusiness logic layer – implements rules and – implements rules and procedures of business processingprocedures of business processing
View layerView layer – accepts user input and formats and – accepts user input and formats and displays processing resultsdisplays processing results
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Three-Layer ArchitectureThree-Layer Architecture
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Service Oriented Architecture (SOA)Service Oriented Architecture (SOA)
A service-oriented architecture is a collection of A service-oriented architecture is a collection of services. These services communicate with each services. These services communicate with each other. The communication can involve either other. The communication can involve either simple data passing or it could involve two or more simple data passing or it could involve two or more services coordinating some activity. Some means services coordinating some activity. Some means of connecting services to each other is needed.of connecting services to each other is needed.
A service is a function that is well-defined, self-A service is a function that is well-defined, self-contained, and does not depend on the context or contained, and does not depend on the context or state of other services. state of other services.
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Service Oriented Architecture (SOA)Service Oriented Architecture (SOA)
The following figure illustrates a basic service-oriented The following figure illustrates a basic service-oriented architecture. architecture.
Both the sender and receiver know how to Both the sender and receiver know how to communicate, but don’t care about the internal communicate, but don’t care about the internal workings of each otherworkings of each other
Services could be within a company, or you could Services could be within a company, or you could access services from another organization – they just access services from another organization – they just need to agreed on how services will communicateneed to agreed on how services will communicate
Web services: SOA using internet and WWW oriented Web services: SOA using internet and WWW oriented technologies. technologies.
XMLXML .Net.Net JavaJava
INFO425: Systems DesignINFO425: Systems Design
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SOA - ExampleSOA - Example
Build a supply chain management system out of Build a supply chain management system out of existing ‘components’ existing ‘components’
Another Company’s inventory system (SAP)
Oracle Manufacturing System
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Web Services ArchitectureWeb Services Architecture
A client/server architectureA client/server architecture Packages software functionality into server Packages software functionality into server
processes (“services”)processes (“services”) Makes services available to applications via Web Makes services available to applications via Web
protocolsprotocols Web services are available to internal and external Web services are available to internal and external
applications applications Developers can assemble an application using existing Web Developers can assemble an application using existing Web
servicesservices
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Internet and Web-Based Application Internet and Web-Based Application ArchitectureArchitecture
Web is complex example of client/server Web is complex example of client/server architecturearchitecture
Can use Web protocols and browsers as Can use Web protocols and browsers as application interfacesapplication interfaces
BenefitsBenefits AccessibilityAccessibility Low-cost communicationLow-cost communication Widely implemented standardsWidely implemented standards
INFO425: Systems DesignINFO425: Systems Design
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Negative Aspects of Negative Aspects of Internet Application DeliveryInternet Application Delivery
Breaches of securityBreaches of security
Fluctuating reliability of network throughputFluctuating reliability of network throughput
Throughput can be limitedThroughput can be limited
Volatile, changing standardsVolatile, changing standards
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
MiddlewareMiddleware
Aspect of distributed computing Aspect of distributed computing
Connects parts of an application and enables Connects parts of an application and enables requests and data to pass between themrequests and data to pass between them
Transaction process monitors, object request Transaction process monitors, object request brokers (ORBs), Web services directoriesbrokers (ORBs), Web services directories
Designers reply on standard frameworks and Designers reply on standard frameworks and protocols incorporated into middlewareprotocols incorporated into middleware
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Enterprise Application Integration (EAI)Enterprise Application Integration (EAI)
Provides the means to share data between Provides the means to share data between different applications without writing custom different applications without writing custom interfaces.interfaces.
Example:Example: Consider a company that wants to do build an eCommerce Consider a company that wants to do build an eCommerce
portal.portal. Has a number of legacy applications (or even an ERP solution Has a number of legacy applications (or even an ERP solution
in place)in place) Need build the web-based eCommerce infrastructure and link Need build the web-based eCommerce infrastructure and link
with systems that do functions like process orders, manage with systems that do functions like process orders, manage inventory, ship productsinventory, ship products
The company decides to use a major courier service for The company decides to use a major courier service for delivery of products ordered from the web site. delivery of products ordered from the web site.
The company wants an ODS for analysis of transactions taking The company wants an ODS for analysis of transactions taking place on the siteplace on the site
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Example Example
eComSite
Courier
Shipping
Inventory
OrderSystem
One solution – custom InterfacesIssues?
ODS
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
ExampleExample
eComSite
Courier
Shipping
Inventory
OrderSystem
ODSEAI
Alternative – employ EAI solution = Middleware
INFO425: Systems DesignINFO425: Systems Design
INFORMATION SYSTEMS @ XINFORMATION SYSTEMS @ X
Advantages of EAIAdvantages of EAI
Cost effectivenessCost effectiveness Time to marketTime to market ScalabilityScalability Ability to deal with complex environmentsAbility to deal with complex environments
INFO425: Systems DesignINFO425: Systems Design
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SummarySummary
Systems design is process of organizing and Systems design is process of organizing and structuring components of system to allow structuring components of system to allow construction (programming) of new systemconstruction (programming) of new system
Design phase of project consists of activities that Design phase of project consists of activities that relate to design of components of new systemrelate to design of components of new system
Application architecture, user interfaces, system interfaces, Application architecture, user interfaces, system interfaces, databases, network diagrams, system controlsdatabases, network diagrams, system controls
Prototyping may be required to specify any part or all of the Prototyping may be required to specify any part or all of the designdesign
INFO425: Systems DesignINFO425: Systems Design
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Summary (Summary (continuedcontinued))
Inputs to design activities are diagrams built Inputs to design activities are diagrams built during analysisduring analysis
Outputs of design are also diagrams that describe Outputs of design are also diagrams that describe architecture of new system and detailed logic of architecture of new system and detailed logic of programming componentsprogramming components
Inputs, design activities, and outputs are different Inputs, design activities, and outputs are different depending on whether a structured approach or an depending on whether a structured approach or an object-oriented approach is usedobject-oriented approach is used
Architectural design adapts to development Architectural design adapts to development environment and decomposes design into layersenvironment and decomposes design into layers