1 Architecture MIS 5003
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ArchitectureMIS 5003
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Architecture
Components and the relationships among them.
Program architectureApplication architectureEnterprise system architecture
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Program Architecture
A part of the system design processDefine sub-programsDefine program modulesDefine data storesSpecify the calling sequences
e.g. System flow charts & Functional Hierarchy Diagrams
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Application Architecture
Structure of a particular application.Databases and program componentsDevices and operating environments on
which these runCommunication links among the devices
Application architecture must take into account the enterprise architecture and its current load.
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Enterprise Architecture
Structure of clients, servers, operating environments, networks and security used to support the enterprise applications.
Usually too expensive to be justified by a single application
Generally defines standards to which applications must adhere
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What is Enterprise System Architecture?Narrow - Hardware, Operating
System and other System Software, DBMS & Network
Broad - Add: Application Programs, Design Tools, Physical Layout, Policies and Procedures
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Principles for the Ideal ArchitectureOpen, High Performance/Cost Immediate AvailabilityInfinitely ScaleableCompletely Secure, Failure FreeInexpensive, Rapid ChangeHigh Level of User ControlLittle or no Training Required
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The ISSUE for this Class
How does a person make “good” decisions in selecting architectures or components
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Different ViewsBusiness View
Reach, range, response & riskConceptual View
Nodes, application mix, performance parameters & security plan
Design ViewNetwork design, server specifications,
operating systems and middleware, program decomposition, segmentation and firewalls
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Business ViewReach: locations for
deliveryRange: application
mixResponse: deferred,
real time, interactiveRisk:
threat*success*cost
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Conceptual View
Translation of user needs into technical specifications.
Functionality at each nodeData and process demands for the
systemDialog expectations and processing
turnaround needsSecurity objectives
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Design ViewDistribution of functions across nodesLocation of data and access proceduresNode specifications (or specifications of
existing nodes)Location of firewalls and use of added
security such as encryptionLink specifications and interconnection
design
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Base Architecture
Mainframes -- few new applications; used mostly for legacy ones
Client/Server -- most new applications; main direction for next several years
NetCentric -- important new area; will it take over some or all
Combinations -- case for most systems
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Mainframe Architecture -- 1990Proprietary $100,000/MIPSYears to DeliverDifficult to ScaleChange DifficultRemote Users Works Well!
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Mainframe Architecture in 2000
$2,000 per MIPSOpen architectureNow a Network Server as wellShort Delivery time Excellent operating systems &
supportIncreased scalabilityLarge set of existing programs
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Distributed System Characteristics - 1999Open, <$100/MIPSShort AvailabilityGood ScalabilityMore User ControlMore Likely to FailCostly Training Costly to MaintainPolicy control Issue
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Distributed Architectures
ServerServer
ClientClient
MainframeMainframeSystemsSystems
Stand AloneStand AlonePCPC
FatFatClientClient
ThinThinClientClient
Amount of WorkAmount of Work
Netcentric
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TelecommunicationsEssential Link for Distributed
SystemsArea and Control
Local (LAN) - nearby, private Wide (WAN) - further away, public
Specifications - capacity or speedTechnology
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NetCentric Systems
Intranets - Standard Browser & Protocol (TCP/IP)
Central Control of Intranet, some Applications, some Servers
Fast Approach to a Global SystemAllows Local Autonomy
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Electronic Commerce (EDI)
Issues: Cost, Elapsed Time, AccessBasic EDI-- electronic transactions,
data flows, reportsElectronic markets and productsElectronic OutsourcingElectronic Virtual Firms
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Electronic Commerce (B2C)Issues: how do we use it.Reliability, accessibility, security.Electronic effects on traditional brick
and mortar business.Advertisement, electronic
registration, transaction processing, customer relationship management.
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Broad Issues For Architectures
Business FunctionsCompany Preferences InteroperabilitySecurityReliability / AvailabilitySystem Management Tools Cost / Effectiveness
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Company Culture
IS Priority of the Responsible ManagerPerceived Performance of Current IS Risk & Failure ToleranceChange ToleranceDesire to LeadExperience BaseSkills Base
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Base Technologies I
High Performance/Cost, multi-chip Servers
Relational &/or Object DBMSFast, switched Ethernet, RoutersInternet II, faster, lower cost WANSElectronic signatures, high security
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Base Technologies II
Multiple Architecture StructuresHigh Levels of CompetitionHigh Innovation RatesIncreasing Business and
Strategic Importance of IS Increasing IS visibility
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Security in Distributed SystemsPasswords - one or multipleAuthenticationAccess Control ListsFirewallsEncryption & Electronic SignaturesSecurity Failure DetectionDamage Control and Correction
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Availability ProtectionPhysical Control / ProtectionShadow Systems / LocationsMirror DatabasesRAID - Redundant Arrays of
Inexpensive DisksFault Tolerant ServersSystem Backups - Secure Storage
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Vendors & Outsourcing
General Opinion -- consultants, other users, open literature
Direct Prior ExperiencesSpecifics-- Warranty Experience,
Customer Service, Response Time, Update Policy, Industry Position, Longevity
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Future ForecastsTechnologiesVendorsIS SkillsBusiness
FunctionsMarkets
You have no future!
CIO
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Futures I
Multiple ArchitecturesWidespread Electronic CommerceIncreased Competition - Downsize,
Reorganize, Merge, FailSystem Design - Still Difficult,
Expensive and High Risk
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Futures IIContinue New Technologies -
Fast/Large everything, Voice, non-silicon processors/storage
Hardware Cost/Performance Telecommunications improvementsReduce labor cost - - CASE,
Package Programs, Outsourcing.
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Technology Assessment
Winning technologies generally have:Low costEarly introductionGood enough performanceMarket share
Most technology innovations have evolved into one or two dominant products over time.