IT ARCHITECTURE

© Holmes Miller 1999

BUILDING METAPHOR

CUSTOMER’S CONCERN Has vision about building that will meet

needs and desiresARCHITECT’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 possibleIT ARCHITECT’S CONCERN Desired system functions and appropriate

technology

COMPONENTS

HardwareSoftwareDataCommunications links

HARDWARE COMPONENTS

Central processing unitPrimary storageSecondary storageInput devicesOutput devicesTelecommunications links

SOFTWARE COMPONENTS

Operating system softwareApplication software

DATABASES

Database hierarchy is:BitByteFieldRecordFileDatabase

DATABASE ORGANIZATION

SEQUENTIAL ORGANIZATION Tape oriented - one file follows

anotherDIRECT 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

COMPONENTSData definition languageDatabase management softwareData dictionary

DATABASE TYPES

HIERARCHIAL One to ManyNETWORK Many to ManyRELATIONAL Use Table format

DATABASE PROS & CONS

HIERARCHIAL High efficiency - Low flexibilityNETWORK Medium efficiency - Medium flexibilityRELATIONAL 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 TRENDSDATA 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

INFORMATIONDIRECTORY

INTERNALDATASOURCES

EXTERNALDATASOURCES

OPERATIONAL,HISTORICAL DATA

DATA WAREHOUSE

EXTRACT,TRANSFORM

DATAACCESS &ANALYSIS

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

DATABASE MANAGEMENT

SYSTEM

DATA

ADMINISTRATION DATABASETECHNOLOGY & MANAGEMENT

USERS

DATA PLANNING & MODELING

METHODOLOGY

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 ISSUESOn-going business processCentral vs. local controlStandardsVendorsRules & policies

DEVELOPING AN ARCHITECTURE

OVERALL PROCEDUREWhere are we now?Where do we want to be?How should we get there?TWO APPROACHESEvolutionaryRevolutionary

DEVELOPING AN ARCHITECTURE

FIVE STEPSArticulate the business strategy and architecture

implicationsBaseline the company architectureDetermine key architecture questionsDesign the blueprintInitiate the architecture plan

CAPITAL BUDGETING MODELSLIMITATIONS: Assume all relevant alternatives

have been examined; cost & benefits can be expressed as $$

Ignore intangible benefits

UNDERSTANDING BUSINESS VALUE OF INFO SYSTEMS

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:HardwareSoftwareServicesPersonnel

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

Costs & Benefits:

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