Transcript IT ARCHITECTURE

IT
ARCHITECTURE
© Holmes Miller 1999
BUILDING METAPHOR
 CUSTOMER’S CONCERN
Has vision about building that will meet
needs and desires
 ARCHITECT’S CONCERN
Translates the vision into a plan to construct the
building
ANALOGOUS TO A BUILDING
 GENERAL MANAGER’S CONCERN
Applications to use, data that will be accessible,
and communications that will be possible
 IT ARCHITECT’S CONCERN
Desired system functions and appropriate
technology
COMPONENTS
 Hardware
 Software
 Data
 Communications links
HARDWARE COMPONENTS
 Central processing unit
 Primary storage
 Secondary storage
 Input devices
 Output devices
 Telecommunications links
SOFTWARE COMPONENTS
Operating system software
Application software
DATABASES
Database hierarchy is:
 Bit
 Byte
 Field
 Record
 File
 Database
DATABASE ORGANIZATION
 SEQUENTIAL ORGANIZATION
Tape oriented - one file follows another
 DIRECT ORGANIZATION
Disk oriented - can be accessed without
regard to physical sequence
DATABASE MANAGEMENT
SYSTEMS
 STORED IN WAY FOR DIFFERENT
BUSINESSES TO ACCESS THE SAME
DATA
 COMPONENTS
Data definition language
Database management software
Data dictionary
DATABASE TYPES
 HIERARCHIAL
One to Many
 NETWORK
Many to Many
 RELATIONAL
Use Table format
DATABASE PROS & CONS
 HIERARCHIAL
High efficiency - Low flexibility
 NETWORK
Medium efficiency - Medium flexibility
 RELATIONAL
Low efficiency - High flexibility
DATABASE TRENDS
 DISTRIBUTED PROCESSING
Multiple systems connected via a network
 DISTRIBUTED DATABASE
Data physically stored in more than one
location
 DATA WAREHOUSE
Consolidate current & historical information - Data Mining!
DATABASE TRENDS
 DATA WAREHOUSE: Organization’s
electronic library stores consolidated
current & historic data for
management reporting & analysis
 DATA MART: Small data warehouse
for special function, e.G.,
Focused marketing based
on customer info
COMPONENTS OF DATA WAREHOUSE
OPERATIONAL,
HISTORICAL DATA
INTERNAL
DATA
SOURCES
DATA WAREHOUSE
DATA
ACCESS &
ANALYSIS
EXTRACT,
TRANSFORM
INFORMATION
DIRECTORY
EXTERNAL
DATA
SOURCES
QUERIES &
REPORTS
OLAP
DATA MINING
DATABASE TRENDS
 ON-LINE ANALYTICAL PROCESSING
(OLAP): ability to manipulate, analyze large
volumes of data from multiple perspectives
 LINKING DATABASES TO THE WEB
ELEMENTS OF DATABASE
ENVIRONMENT
DATA
DATABASE
TECHNO
LOGY &
MANAGEMENT
ADMINISTRATION
DATABASE
MANAGEMENT
SYSTEM
DATA PLANNING
& MODELING
METHODOLOGY
USERS
COMMUNICATIONS LINKS
 NETWORKS
Hardware and software that permits
computer-computer or computer-peripheral
communication
 COMMUNICATIONS DEVICES
Hardware devices to control communication
in a computer system
DEVELOPING AN ARCHITECTURE
SOME ISSUES
 On-going business process
 Central vs. local control
 Standards
 Vendors
 Rules & policies
DEVELOPING AN ARCHITECTURE
OVERALL PROCEDURE
 Where are we now?
 Where do we want to be?
 How should we get there?
TWO APPROACHES
 Evolutionary
 Revolutionary
DEVELOPING AN ARCHITECTURE
FIVE STEPS
 Articulate the business strategy and
architecture implications
 Baseline the company architecture
 Determine key architecture questions
 Design the blueprint
 Initiate the architecture plan
UNDERSTANDING BUSINESS
VALUE OF INFO SYSTEMS
CAPITAL BUDGETING MODELS
LIMITATIONS:
 Assume all relevant alternatives have
been examined; cost & benefits can
be expressed as $$
 Ignore intangible benefits
Capital Budget:
Process of analyzing, selecting capital
expenditures
 Payback method
 Return on investment
 Cost-benefit ratio
 Net present value
 Profitability index
 Internal rate of return
Costs & Benefits:
Costs:
Hardware
Software
Services
Personnel
Costs & Benefits:
Tangible benefit:
 Increased productivity
 Low operating costs
 Reduced work force
 Lower computer expenses
 Lower vendor costs
 Lower clerical/professional costs
 Reduced growth of expenses
 Reduced facility costs
Costs & Benefits:
Intangible benefit:
 Improved asset use; resource control; planning
 Increased flexibility
 More timely information
 Increased learning
 Attain legal requirements
 Enhanced employee goodwill, job satisfaction,
decision making, operations
 Higher client satisfaction
 Better corporate image
Portfolio Analysis:
Analysis of potential applications to determine risks
& benefits
 Determine desirable features, acceptable risks of
required system
 Generate portfolio of characteristics, risks for
each alternative
 Scoring model