© prentice hall 2002 8.1 chapter 8 basic information systems concepts

8.1

© Prentice Hall 2002

CHAPTER 8CHAPTER 8

Basic Information Basic Information SystemsSystems

ConceptsConcepts

8.2


SYSTEMS VIEWSYSTEMS VIEW

• FRAMEWORK FOR SEEING FRAMEWORK FOR SEEING INTERRELATIONSHIPSINTERRELATIONSHIPS

• SYSTEM: SYSTEM: Set of interrelated components Set of interrelated components working together to achieve common working together to achieve common purposepurpose

• INFORMATION SYSTEM INFORMATION SYSTEM (IS)(IS): : Collection Collection of information technology, procedures, & of information technology, procedures, & people that captures, moves, manages, people that captures, moves, manages, distributes data & informationdistributes data & information

**

8.3


SYSTEMSYSTEMBOUNDARYBOUNDARY

GENERAL STRUCTURE OF SYSTEMGENERAL STRUCTURE OF SYSTEMENVIRONMENTENVIRONMENT

COMPONENT 2

InterfaceInput 2

InterfaceCOMPONENT 3

Input 1STORAGE 1

COMPONENT 2

Interface

Output 1

8.4


SYSTEM BOUNDARYSYSTEM BOUNDARY

• DIVIDING LINEDIVIDING LINE• PLACED BASED ON THE PURPOSE: PLACED BASED ON THE PURPOSE:

Usually not a fixed lineUsually not a fixed line• CONTROL OR REDESIGN WITHIN CONTROL OR REDESIGN WITHIN

THE BOUNDARYTHE BOUNDARY• ENVIRONMENT OUTSIDE THE ENVIRONMENT OUTSIDE THE

BOUNDARYBOUNDARY

**

8.5


SYSTEM BOUNDARYSYSTEM BOUNDARY

• WHAT CAN BE CONTROLLED: WHAT CAN BE CONTROLLED: External elements are constraintsExternal elements are constraints

• WHAT SCOPE MANAGEABLE WITHIN WHAT SCOPE MANAGEABLE WITHIN GIVEN TIME PERIOD: GIVEN TIME PERIOD: Complex Complex systems take longer to design, modifysystems take longer to design, modify

• WHAT IS IMPACT OF BOUNDARY WHAT IS IMPACT OF BOUNDARY CHANGE: CHANGE: Dynamic changes require Dynamic changes require accommodationaccommodation

**

8.6


COMPONENT DECOMPOSITIONCOMPONENT DECOMPOSITION

• BREAK SYSTEM INTO BREAK SYSTEM INTO SUBSYSTEMSSUBSYSTEMS

• COMPONENTS OF SUBSYSTEM COMPONENTS OF SUBSYSTEM MAY FORM MORE SUBSYSTEMSMAY FORM MORE SUBSYSTEMS

• OFTEN SUBSYSTEMS ARE EASIER OFTEN SUBSYSTEMS ARE EASIER TO UNDERSTAND, CREATE, TO UNDERSTAND, CREATE, MODIFYMODIFY

**

8.7


GOALS OF HIERARCHICAL GOALS OF HIERARCHICAL DECOMPOSITIONDECOMPOSITION

1. 1. COPE WITH COMPLEXITY OF SYSTEMCOPE WITH COMPLEXITY OF SYSTEM

2. 2. ANALYZE OR CHANGE ONLY PART OF ANALYZE OR CHANGE ONLY PART OF SYSTEMSYSTEM

3. 3. DESIGN, BUILD SUBSYSTEMS AT DESIGN, BUILD SUBSYSTEMS AT DIFFERENT TIMESDIFFERENT TIMES

4. 4. DIRECT ATTENTION OF TARGET DIRECT ATTENTION OF TARGET AUDIENCEAUDIENCE

5. 5. ALLOW COMPONENTS TO OPERATE ALLOW COMPONENTS TO OPERATE INDEPENDENTLYINDEPENDENTLY

**

8.8


FUNDAMENTAL COMPONENTS FUNDAMENTAL COMPONENTS OF ORGANIZATIONOF ORGANIZATION

• PEOPLEPEOPLE• INFORMATION TECHNOLOGYINFORMATION TECHNOLOGY• BUSINESS PROCESSESBUSINESS PROCESSES• ORGANIZATIONAL STRUCTUREORGANIZATIONAL STRUCTURE

EACH IMPACTS THE REST!EACH IMPACTS THE REST!**

8.9


DECISION MAKING DECISION MAKING PROCESSPROCESS

• INTELLIGENCE: INTELLIGENCE: Search for needs, collect dataSearch for needs, collect data

• DESIGN: DESIGN: Generate alternatives, test feasibilityGenerate alternatives, test feasibility

• CHOICE: CHOICE: Select from alternativesSelect from alternatives

• PERSUASION: PERSUASION: Influencing others to accept & Influencing others to accept & follow chosen solutionfollow chosen solution

• IMPLEMENTATION: IMPLEMENTATION: Install solution on time, Install solution on time, within budgetwithin budget

• FOLLOW-UP: FOLLOW-UP: Monitor, modify, refineMonitor, modify, refine

CONSTANT FEEDBACKCONSTANT FEEDBACK

**

8.10


BUSINESS PROCESSESBUSINESS PROCESSES

A SET OF WORK ACTIVITIES & A SET OF WORK ACTIVITIES & RESOURCESRESOURCES

• IDENTIFYIDENTIFY• EVALUATEEVALUATE• REDESIGNREDESIGN

USE INFORMATION TECHNOLOGYUSE INFORMATION TECHNOLOGY (IT)(IT) TO BREAK RULES!TO BREAK RULES!

* *

8.11


EVALUATING A PROCESS EVALUATING A PROCESS XX

• DOES DOES XX DEFINE FIRM TO CUSTOMERS, DEFINE FIRM TO CUSTOMERS, EMPLOYEES, INVESTORS?EMPLOYEES, INVESTORS?– YES: IDENTIFY– NO: GO ON

• IS EXCELLING AT IS EXCELLING AT XX CRITICAL TO CRITICAL TO BUSINESS?BUSINESS?– YES: PRIORITY– NO: GO ON

**

8.12


EVALUATING A PROCESS EVALUATING A PROCESS XX

• DOES DOES XX SUPPORT OTHER SUPPORT OTHER PROCESSES?PROCESSES?– YES: BACKGROUND– NO: GO ON

• IS IS XX CARRIED OUT ONLY BECAUSE CARRIED OUT ONLY BECAUSE IT IS LEGALLY REQUIRED?IT IS LEGALLY REQUIRED?– YES: MANDATED– NO: FOLKLORE > ABANDON

**

8.13


BUSINESS PROCESS REDESIGN*BUSINESS PROCESS REDESIGN*

• START WITH “CLEAN SLATE”START WITH “CLEAN SLATE”• USE USE ITIT TO RADICALLY CHANGE TO RADICALLY CHANGE

PROCESSESPROCESSES• QUESTION ASSUMPTIONS & RULESQUESTION ASSUMPTIONS & RULES• ASK “WHY?”, “WHAT IF?”, “WHO ASK “WHY?”, “WHAT IF?”, “WHO

SAYS SO?”, “WHAT DO SAYS SO?”, “WHAT DO CUSTOMERS THINK?”CUSTOMERS THINK?”

***Hammer, 1990

8.14


USING USING ITIT TO BREAK DYSFUNCTIONAL TO BREAK DYSFUNCTIONAL

RULES*RULES*

• OLD RULE: OLD RULE: Information can appear in Information can appear in only one place at one time.only one place at one time.

• DISRUPTIVE TECHNOLOGY: DISRUPTIVE TECHNOLOGY: Shared databasesShared databases

• NEW RULE: NEW RULE: Information can be used Information can be used simultaneously in many placessimultaneously in many places

**

Example #1

*Hammer & Chanmpy, 1993

8.15


• OLD RULE: OLD RULE: Only EXPERTS do complex Only EXPERTS do complex work.work.

• DISRUPTIVE TECHNOLOGY: DISRUPTIVE TECHNOLOGY: Expert systemsExpert systems

• NEW RULE: NEW RULE: Generalists can do Generalists can do complex work like an EXPERTcomplex work like an EXPERT

***Hammer & Chanmpy, 1993


RULES*RULES*

Example #2

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• OLD RULE: OLD RULE: Field personnel need Field personnel need OFFICES to receive, store, retrieve, and OFFICES to receive, store, retrieve, and transmit information.transmit information.

• DISRUPTIVE TECHNOLOGY: DISRUPTIVE TECHNOLOGY: Portable Portable and home computers, modems, and and home computers, modems, and wireless data communicationwireless data communication

• NEW RULE: NEW RULE: Field personnel send and Field personnel send and receive information WHEREVER they arereceive information WHEREVER they are

***Hammer & Chanmpy, 1993


RULES*RULES*

Example #3

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PRINCIPLES FOR PRINCIPLES FOR REDESIGNING PROCESSES*REDESIGNING PROCESSES*

1.1.ORGANIZE AROUND ORGANIZE AROUND OUTCOMES, NOT TASKSOUTCOMES, NOT TASKS

2.2.ASSIGN USERS OF OUTPUT TO ASSIGN USERS OF OUTPUT TO PERFORM PROCESSPERFORM PROCESS

3.3.INTEGRATE INFORMATION INTEGRATE INFORMATION PROCESSING INTO WORK THAT PROCESSING INTO WORK THAT PRODUCES INFORMATIONPRODUCES INFORMATION

***Hammer, 1990

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4.4.CREATE VIRTUAL ENTERPRISE BY CREATE VIRTUAL ENTERPRISE BY TREATING GEOGRAPHICALLY TREATING GEOGRAPHICALLY DISTRIBUTED RESOURCES AS DISTRIBUTED RESOURCES AS THOUGH THEY WERE THOUGH THEY WERE CENTRALIZEDCENTRALIZED

5.5.LINK PARALLEL ACTIVITIES LINK PARALLEL ACTIVITIES INSTEAD OF INTEGRATING THEIR INSTEAD OF INTEGRATING THEIR RESULTSRESULTS

* * *Hammer, 1990

8.19



6.6.HAVE PEOPLE WHO DO WORK HAVE PEOPLE WHO DO WORK MAKE DECISIONS, MONITOR MAKE DECISIONS, MONITOR PROCESS BY BUILT-IN PROCESS BY BUILT-IN CONTROLSCONTROLS

**

*Hammer, 1990

8.20


INFORMATION SYSTEMS LIFE INFORMATION SYSTEMS LIFE CYCLECYCLE

• DEFINITION PHASE: DEFINITION PHASE: End-users & End-users & analysts conduct analysis analysts conduct analysis

• CONSTRUCTION: CONSTRUCTION: Use of Use of structured techniques, system structured techniques, system development methodologydevelopment methodology

• IMPLEMENTATION: IMPLEMENTATION: Plan, test, Plan, test, train, accept, monitortrain, accept, monitor

**

8.21


LOGIC TO-BE MODELLOGIC TO-BE MODELSYMBOLSSYMBOLS

ELEMENT SENDING OR RECEIVING DATA. NAMES ARE NOUN LABELS

DATA IN MOTION BETWEEN ELEMENTS. NAMES ARE NOUNS OR NUMBERS

PROCESSES WITH INPUT & OUTPUT. NAMES ARE VERB PHRASES & NUMBERS

DATA STORE WITH INPUT & OUTPUT. NAMES ARE NOUNS & NUMBERS

*

8.22


LOGIC TO-BE MODELLOGIC TO-BE MODELPROCESSESPROCESSES

• IDENTIFY ENTITIES THAT SUPPLY, USE IDENTIFY ENTITIES THAT SUPPLY, USE SYSTEM INFORMATIONSYSTEM INFORMATION

• DISTINGUISH PROCESSES FROM DATA DISTINGUISH PROCESSES FROM DATA THEY USE OR PRODUCETHEY USE OR PRODUCE

• EXPLICATES RULES AFFECTING EXPLICATES RULES AFFECTING CHANGING DATA TO INFORMATIONCHANGING DATA TO INFORMATION

• IDENTIFY LOGICAL RELATIONSHIPS IDENTIFY LOGICAL RELATIONSHIPS • PINPOINT DUPLICATE STORAGE, PINPOINT DUPLICATE STORAGE,

MOVEMENT OF DATAMOVEMENT OF DATA

**

8.23


WORK PROCESS FLOW SYMBOLSWORK PROCESS FLOW SYMBOLS::

DOCUMENT

DATABASE

ON-LINE DISPLAY TELECOMMUNICATIONS LINK

INPUT/OUTPUT PROCESS MAGNETIC TAPE

PUNCHED CARD MANUAL OPERATION ON-LINE STORAGE

ON-LINE INPUT

8.24


PROGRAM FLOWCHART PROGRAM FLOWCHART SYMBOLS:SYMBOLS:

BEGIN OREND

DIRECTION

PROCESS

DECISION

INPUT OROUTPUT

SUBROUTINE

MANUALOPERATION

CONNECTOR

8.25


OBJECT-ORIENTED OBJECT-ORIENTED TECHNIQUESTECHNIQUES

• KEY IDEA:KEY IDEA: Work with reusable objects to Work with reusable objects to speed up development!speed up development!

TWO PRINCIPLES:TWO PRINCIPLES:• ENCAPSULATION: ENCAPSULATION: Store data and Store data and

related operations together within objectsrelated operations together within objects

• INHERITANCE: INHERITANCE: Share common Share common characteristics between classes of objectscharacteristics between classes of objects

**

8.26


OBJECT-ORIENTED OBJECT-ORIENTED APPROACHAPPROACH

• DEFINE TASK: DEFINE TASK: Search library of Search library of existing objects useful to taskexisting objects useful to task

• PROCESS: PROCESS: Create bare-bones Create bare-bones prototype, test, provide critical prototype, test, provide critical feedback, repeat & refinefeedback, repeat & refine

• ELAPSED TIME: ELAPSED TIME: Can be weeksCan be weeks

**

8.27


ITIT-RELATED RISKS-RELATED RISKS

• ORGANIZATIONAL RISKS: ORGANIZATIONAL RISKS: From From changes in environmentchanges in environment

• PERSONNEL RISKS: PERSONNEL RISKS: From loss of From loss of expertise, system use (or non-use)expertise, system use (or non-use)

• SYSTEM PROJECT RISKS: SYSTEM PROJECT RISKS: From From project management deficienciesproject management deficiencies

• EXTERNAL SECURITY RISKS: EXTERNAL SECURITY RISKS: Criminal acts, natural disastersCriminal acts, natural disasters

**

8.28


LIFE CYCLE CONTROLSLIFE CYCLE CONTROLS

• DEFINITION & CONSTRUCTION:DEFINITION & CONSTRUCTION:– Methodology standards– Validation rules & calculations– System testing

• IMPLEMENTATION:IMPLEMENTATION:– Security– Backup & recovery– Auditing Roles

**

8.29


CHAPTER 8CHAPTER 8

Basic Information Basic Information SystemsSystems

ConceptsConcepts

© prentice hall 2002 8.1 chapter 8 basic information systems concepts

Documents

prentice hall

subsystemsbreak system

interrelationships system

complexity of system

boundary environment

impact of boundary change

interface component

interrelated components