Selecting the Best Architecture

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Selecting the Best Architecture

• MIS 4663

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What is 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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Another Viewpoint

• Architecture - a broad system plan, for example
  client/server or mainframe
• Infrastructure - components used to implement an
  architecture

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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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Architectures over Time

• Language - symbols with meaning
• Printing - lower cost technology
• Electrical DP - punched cards
• Mainframe - begin Electronic DP
• Distributed - Client/Server, etc.
• Netcentric - Standard Browser
• Next?

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Mainframe Architecture -- 1990Forty years of
History

• Proprietary
• 100,000/MIPS
• Years to Deliver
• Difficult to Scale
• Change Difficult
• Remote Users
• Works Well!

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Concepts and Principles for the Ideal Architecture

• Open, High Performance/Cost
• Immediate Availability
• Infinitely Scaleable
• Completely Secure, Failure Free
• Inexpensive, Rapid Change
• High Level of User Control
• Little or no Training Required

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Mainframe Architecture in 2000

• 2,000 per MIPS
• Open architecture
• Now a Network Server as well
• Short Delivery time
• Excellent operating systems support
• Increased scalability
• Large set of existing programs

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Distributed System Characteristics - 1999

• Open, lt100/MIPS
• Short Availability
• Good Scalability
• More User Control
• More Likely to Fail
• Costly Training
• Costly to Maintain
• Policy control Issue

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Distributed Architectures
Amount of Work
Server
Client
Netcentric
Stand Alone PC
Mainframe Systems
Thin Client
Fat Client
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Telecommunications

• Essential Link for Distributed Systems
• Area and Control
• Local (LAN) - nearby, private
• Wide (WAN) - further away, public
• Specifications - capacity or speed
• Technology

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Mainframe Point to Point
Front End
Terminals
Mainframe
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Network
Workstations
Server
Network
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Electronic Commerce (EDI)

• Issues Cost, Elasped Time, Access
• Basic EDI-- electronic transactions, data flows,
  reports
• Electronic markets and products
• Electronic Outsourcing
• Electronic Virtual Firms

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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 Automony

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Broad Issues For Architectures

• Business Functions
• Company Preferences
• Interoperability
• Security
• Reliability / Availability
• System Management Tools
• Cost / Effectiveness

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Cost/Performance Tradeoff
Performance
x
x
High
x
Efficient Surface
x
x
x
x
x
x
x
Dominance
High
Cost
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General Architecture Selection Model
Decision to Change
Technology Environment
Problem Environment
Selection Decisions
Architecture Package
Experience Adjustments
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Selecting A 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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Business Environment
Company Culture
Market Competitors
Business Process
Business Environment Weights
Future Forecast
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Company Culture

• IS Priority of the Responsible Manager
• Perceived Performance of Current IS
• Risk Failure Tolerance
• Change Tolerance
• Desire to Lead
• Experience Base
• Skills Base

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Technology Environment
Future Forecasts
Base Technologies
Vendors
Evaluation Process
Technology Packages
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Base Technologies I

• High Performance/Cost, multi-chip Servers
• Relational /or Object DBMS
• Fast, switched Ethernet, Routers
• Internet II, faster, lower cost WANS
• Electronic signatures, high security

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Base Technologies II

• Multiple Architecture Structures
• High Levels of Competition
• High Innovation Rates
• Increasing Business and Strategic Importance of
  IS
• Increasing IS visibility

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Security in Distributed Systems

• Passwords - one or multiple
• Authentication
• Access Control Lists
• Firewalls
• Encryption Electronic Signatures
• Security Failure Detection
• Damage Control and Correction

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Availability Enhancement

• Physical Control / Protection
• Shadow Systems / Locations
• Mirror Databases
• RAID - Redundant Arrays of Inexpensive Disks
• Fault Tolerant Servers
• System Backups - Secure Storage

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Vendors

• General Opinion -- consultants, other users, open
  literature
• Direct Prior Experiences
• Specifics-- Warranty Experience, Customer
  Service, Response Time, Update Policy, Industry
  Position, Longevity

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Future Forecasts

• Technologies
• Vendors
• IS Skills
• Business Functions
• Markets

You have no future!
CIO
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Futures I

• Multiple Architectures
• Widespread Electronic Commerce
• Increased Competition - Downsize, Reorganize,
  Merge, Fail
• System 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 improvements
• Reduce labor cost - - CASE, Package Programs,
  Outsourcing.