Transcript IS Architecture

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
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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:
threat*success*cost
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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, <$100/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
Mainframe
Systems
Netcentric
Thin
Client
Fat
Client
Stand Alone
PC
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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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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, nonsilicon 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.
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