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Architecture

MIS 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 Architecture

Open, 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 Views

Business ViewReach, range, response & risk

Conceptual ViewNodes, application mix, performance

parameters & security planDesign View

Network design, server specifications, operating systems and middleware, program decomposition, segmentation and firewalls

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Business View

Reach: locations for delivery

Range: application mix

Response: deferred, real time, interactive

Risk: 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 View

Distribution 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 -- 1990

Proprietary $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 - 1999

Open, <$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 System

Allows Local Autonomy

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Electronic Commerce (EDI)

Issues: Cost, Elapsed Time, Access

Basic EDI-- electronic transactions, data flows, reports

Electronic 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 Systems

Passwords - one or multipleAuthenticationAccess Control ListsFirewallsEncryption & Electronic SignaturesSecurity Failure DetectionDamage Control and Correction

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Availability Protection

Physical 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 Forecasts

TechnologiesVendorsIS 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 II

Continue 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.