Architecture

1
Architecture

• MIS 5003

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Architecture

• Components and the relationships among them.
• Program architecture
• Application architecture
• Enterprise system architecture

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Program Architecture

• A part of the system design process
• Define sub-programs
• Define program modules
• Define data stores
• Specify the calling sequences
• e.g. System flow charts Functional Hierarchy
  Diagrams

4
Application Architecture

• Structure of a particular application.
• Databases and program components
• Devices and operating environments on which these
  run
• Communication 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 Availability
• Infinitely Scaleable
• Completely Secure, Failure Free
• Inexpensive, Rapid Change
• High Level of User Control
• Little 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 View
• Reach, range, response risk
• Conceptual View
• Nodes, application mix, performance parameters
  security plan
• Design 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 threatsuccesscost

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Conceptual View

• Translation of user needs into technical
  specifications.
• Functionality at each node
• Data and process demands for the system
• Dialog expectations and processing turnaround
  needs
• Security objectives

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Design View

• Distribution of functions across nodes
• Location of data and access procedures
• Node specifications (or specifications of
  existing nodes)
• Location of firewalls and use of added security
  such as encryption
• Link 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/MIPS
• Years to Deliver
• Difficult to Scale
• Change Difficult
• Remote Users
• Works Well!

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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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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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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, Elapsed Time, Access
• Basic EDI-- electronic transactions, data flows,
  reports
• Electronic markets and products
• Electronic Outsourcing
• Electronic 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 Functions
• Company Preferences
• Interoperability
• Security
• Reliability / Availability
• System Management Tools
• Cost / Effectiveness

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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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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 Protection

• 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 Outsourcing

• 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.

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Technology Assessment

• Winning technologies generally have
• Low cost
• Early introduction
• Good enough performance
• Market share
• Most technology innovations have evolved into
  one or two dominant products over time.