Appraise System Building

12.1

DATA FLOW DIAGRAMDATA FLOW DIAGRAM::

GENERATE BILL

CUSTOMER

GENERATE BALANCE

GENERATE REPORT

MANAGER

PAYMENTFILE

CUSTOMERFILE

• APPRAISE SYSTEM BUILDING APPRAISE SYSTEM BUILDING ALTERNATIVESALTERNATIVES

• COMPARE STRENGTHS, WEAKNESSES COMPARE STRENGTHS, WEAKNESSES OF APPROACHESOF APPROACHES

• ASSESS SOLUTIONS TO PROBLEMS ASSESS SOLUTIONS TO PROBLEMS CREATED BY APPROACHESCREATED BY APPROACHES

• DESCRIBE TOOLS, METHODOLOGIES OF DESCRIBE TOOLS, METHODOLOGIES OF SYSTEMS DEVELOPMENTSYSTEMS DEVELOPMENT

**

LEARNING OBJECTIVESLEARNING OBJECTIVES

12.2

MANAGEMENT CHALLENGESMANAGEMENT CHALLENGES

• TRADITIONAL SYSTEMS LIFECYCLETRADITIONAL SYSTEMS LIFECYCLE

• ALTERNATIVE SYSTEM-BUILDING ALTERNATIVE SYSTEM-BUILDING APPROACHESAPPROACHES

• SYSTEM-BUILDING SYSTEM-BUILDING METHODOLOGIES & TOOLSMETHODOLOGIES & TOOLS

**

12.3

SYSTEM LIFECYCLESYSTEM LIFECYCLE

• PROJECT DEFINITION:PROJECT DEFINITION: Is there a Is there a problem? Can it be solved with a project?problem? Can it be solved with a project?

• SYSTEM STUDY:SYSTEM STUDY: Analyze problems in Analyze problems in existing systems; define objectives existing systems; define objectives evaluate alternativesevaluate alternatives

• DESIGN:DESIGN: Logical & physical specifications Logical & physical specifications for systems solutionfor systems solution

• PROGRAMMING:PROGRAMMING: Develop software codeDevelop software code

**12.4


• INSTALLATION:INSTALLATION: Construct, test, train, Construct, test, train, convert to new systemconvert to new system

• POSTINSTALLATION:POSTINSTALLATION: On-going On-going evaluation, modifications for improvement evaluation, modifications for improvement to meet new requirementsto meet new requirements

NECESSARY FOR LARGE, COMPLEX NECESSARY FOR LARGE, COMPLEX SYSTEMS & PROJECTSSYSTEMS & PROJECTS

**

12.5


• CAN BE COSTLY, TIME CONSUMINGCAN BE COSTLY, TIME CONSUMING• MAY ENCOURAGE FREEZING MAY ENCOURAGE FREEZING

SPECIFICATIONS EARLY IN SPECIFICATIONS EARLY IN DEVELOPMENTDEVELOPMENT

• MAY NOT BE SUITABLE FOR SMALL, MAY NOT BE SUITABLE FOR SMALL, LESS STRUCTURED SYSTEMSLESS STRUCTURED SYSTEMS

**

12.6

ALTERNATIVE SYSTEM-ALTERNATIVE SYSTEM-BUILDING APPROACHESBUILDING APPROACHES

• PROTOTYPINGPROTOTYPING

• APPLICATION SOFTWARE APPLICATION SOFTWARE PACKAGESPACKAGES

• END-USER DEVELOPMENTEND-USER DEVELOPMENT

• OUTSOURCINGOUTSOURCING

**

12.7

PROTOTYPINGPROTOTYPING PROCESS OF BUILDING EXPERIMENTAL PROCESS OF BUILDING EXPERIMENTAL

SYSTEM TO DEMONSTRATE, EVALUATE SYSTEM TO DEMONSTRATE, EVALUATE APPROACH; USERS REFINE NEEDSAPPROACH; USERS REFINE NEEDS

• PROTOTYPE:PROTOTYPE: Preliminary working Preliminary working version of information system for version of information system for demonstration, evaluation purposesdemonstration, evaluation purposes

• ITERATIVE PROCESSITERATIVE PROCESS

**

12.8

STEPS IN PROTOTYPINGSTEPS IN PROTOTYPING

1. IDENTIFY USER’S REQUIREMENTS1. IDENTIFY USER’S REQUIREMENTS

2, DEVELOP PROTOTYPE2, DEVELOP PROTOTYPE

3, USE PROTOTYPE3, USE PROTOTYPE

4. REVISE & ENHANCE PROTOTYPE4. REVISE & ENHANCE PROTOTYPE

BEST FOR DESIGN OF END-USER BEST FOR DESIGN OF END-USER INTERFACE:INTERFACE: How end-user interacts How end-user interacts with systemwith system

**12.9

APPLICATION SOFTWARE APPLICATION SOFTWARE PACKAGESPACKAGES

PREWRITTEN, PRECODED APPLICATION PREWRITTEN, PRECODED APPLICATION SOFTWARE, COMMERCIALLY SOFTWARE, COMMERCIALLY AVAILABLE FOR SALE OR LEASEAVAILABLE FOR SALE OR LEASE

• GEARED TO COMMON REQUIREMENTSGEARED TO COMMON REQUIREMENTS• CUSTOMIZATION:CUSTOMIZATION: Modification of Modification of

software to meet organization’s needssoftware to meet organization’s needs• MUST WEIGH COSTS / BENEFITSMUST WEIGH COSTS / BENEFITS

**

12.10

SELECTED EXAMPLES OF SELECTED EXAMPLES OF APPLICATION PROGRAMSAPPLICATION PROGRAMS

ACCOUNTS RECEIVABLE; ACCOUNTS RECEIVABLE; BOND & STOCK BOND & STOCK MANAGEMENT; MANAGEMENT; COMPUTER-AIDED DESIGN (CAD) ; COMPUTER-AIDED DESIGN (CAD) ;

DOCUMENT IMAGING;DOCUMENT IMAGING; E- MAIL; E- MAIL; ENTERPRISEENTERPRISE.RESOURCE PLANNING (ERP); RESOURCE PLANNING (ERP);

GROUPWARE; GROUPWARE; HEALTH CARE; HEALTH CARE; HOTELHOTEL.MANAGEMENT; MANAGEMENT; INTERNET TELEPHONE; INTERNET TELEPHONE; INVENTORY CONTROL; INVENTORY CONTROL; JOB JOB

COSTING; COSTING; LIBRARY SYSTEMS; LIBRARY SYSTEMS; LIFE INSURANCE; LIFE INSURANCE; MAILING LABELS; MAILING LABELS; MATHEMATICAL / STATISTICAL MATHEMATICAL / STATISTICAL

MODELING; MODELING; ORDER PROCESSING; ORDER PROCESSING; PAYROLL; PAYROLL; PROCESS CONTROL;PROCESS CONTROL;TAX ACCOUNTING; WEB TAX ACCOUNTING; WEB

BROWSER;BROWSER; WORD PROCESSINGWORD PROCESSING

**

12.11

CUSTOMIZATIONCUSTOMIZATION

MODIFYING SOFTWARE PACKAGE MODIFYING SOFTWARE PACKAGE

TO MEET ORGANIZATION’S UNIQUE TO MEET ORGANIZATION’S UNIQUE REQUIREMENTSREQUIREMENTS

WITHOUT DESTROYING INTEGRITY WITHOUT DESTROYING INTEGRITY OF PACKAGEOF PACKAGE

RAISES DEVELOPMENT COSTSRAISES DEVELOPMENT COSTS

**

12.12

0

2

4

6

8

10

0.5 1 2 3 4 5

% LINES OF CODE CONVERTED% LINES OF CODE CONVERTED

TO

TA

L IM

PL

EM

EN

TA

TIO

NT

OT

AL

IMP

LE

ME

NT

AT

ION

CO

ST

SC

OS

TS

EFFECTS OF CUSTOMIZING SOFTWARE ON EFFECTS OF CUSTOMIZING SOFTWARE ON TOTAL IMPLEMENTATION COSTSTOTAL IMPLEMENTATION COSTS

12.13

• DESCRIPTION (PRESENT, PROPOSED)DESCRIPTION (PRESENT, PROPOSED)• RELIABILITYRELIABILITY• BACKUPBACKUP• SERVICESSERVICES• SYSTEM SPECIFICATIONSSYSTEM SPECIFICATIONS• CRITERIACRITERIA• DEMONSTRATION (PROTOTYPE)DEMONSTRATION (PROTOTYPE)• SCHEDULE (BENCH MARKS)SCHEDULE (BENCH MARKS)• PRICE (PENALTIES)PRICE (PENALTIES)• SPECIFIC QUESTIONSSPECIFIC QUESTIONS• PROCEDURES FOR RESPONSEPROCEDURES FOR RESPONSE

**

REQUEST FOR PROPOSAL (RFPREQUEST FOR PROPOSAL (RFP)

Source: Senn, Information Technology in Business (1995)12.14

END-USER DEVELOPMENTEND-USER DEVELOPMENT

END-USERS DEVELOP INFORMATION END-USERS DEVELOP INFORMATION SYSTEMSYSTEM

WITH LITTLE HELP FROM WITH LITTLE HELP FROM

TECHNICAL SPECIALISTSTECHNICAL SPECIALISTS

USING 4th GENERATION TOOLSUSING 4th GENERATION TOOLS

**

12.15


STRENGTHS:STRENGTHS:• IMPROVED REQUIREMENTS IMPROVED REQUIREMENTS

DETERMINATIONDETERMINATION• INCREASED USER INVOLVEMENT & INCREASED USER INVOLVEMENT &

SATISFACTIONSATISFACTION• REDUCED APPLICATION BACKLOGREDUCED APPLICATION BACKLOG

**

12.16


WEAKNESSES:WEAKNESSES:• RELATIVELY INEFFICIENTRELATIVELY INEFFICIENT• SLOW TRANSACTION PROCESSINGSLOW TRANSACTION PROCESSING• MAY CARRY HIGH COSTMAY CARRY HIGH COST• LARGE FILES CAN DEGRADE PERFORMANCELARGE FILES CAN DEGRADE PERFORMANCE• NONPROCEDURAL APPROACHNONPROCEDURAL APPROACH MAY MAY

HAMPER LOGIC & HAMPER LOGIC & UPDATING UPDATING REQUIREMENTSREQUIREMENTS

**

12.17

MANAGING END-USER MANAGING END-USER DEVELOPMENTDEVELOPMENT

INFORMATION CENTER:INFORMATION CENTER:• SPECIAL FACILITY WITHIN SPECIAL FACILITY WITHIN

ORGANIZATIONORGANIZATION• PROVIDES TRAINING, SUPPORT FOR PROVIDES TRAINING, SUPPORT FOR

END-USER-COMPUTINGEND-USER-COMPUTING

**

12.18

OUTSOURCINGOUTSOURCING

CONTRACTING:CONTRACTING:• COMPUTER CENTER OPERATIONSCOMPUTER CENTER OPERATIONS• TELECOMMUNICATIONS NETWORKSTELECOMMUNICATIONS NETWORKS• APPLICATION DEVELOPMENTAPPLICATION DEVELOPMENT

TO EXTERNAL VENDORSTO EXTERNAL VENDORS

**

12.19

OUTSOURCINGOUTSOURCING

WHEN TO OUTSOURCE:WHEN TO OUTSOURCE:• IF FIRM WON’T DISTINGUISH ITSELF BY IF FIRM WON’T DISTINGUISH ITSELF BY

DEVELOPING APPLICATIONDEVELOPING APPLICATION• PREDICTABILITY OF UNINTERRUPTED PREDICTABILITY OF UNINTERRUPTED

SERVICE NOT IMPORTANTSERVICE NOT IMPORTANT• IF EXISTING SYSTEM IS IF EXISTING SYSTEM IS

LIMITED, INEFFECTIVE, LIMITED, INEFFECTIVE, INFERIORINFERIOR

**12.20

SYSTEM BUILDING SYSTEM BUILDING METHODOLOGIESMETHODOLOGIES

• STRUCTURED METHODOLOGIESSTRUCTURED METHODOLOGIES

• OBJECT- ORIENTED SOFTWARE OBJECT- ORIENTED SOFTWARE DEVELOPMENTDEVELOPMENT

• COMPUTER AIDED SOFTWARE COMPUTER AIDED SOFTWARE ENGINEERING ENGINEERING (CASE)(CASE)

• SOFTWARE REENGINEERINGSOFTWARE REENGINEERING

**

12.21

STRUCTURED STRUCTURED METHODOLOGIESMETHODOLOGIES

TOP DOWN, STEP BY STEP, EACH TOP DOWN, STEP BY STEP, EACH STEP BUILDS ON PREVIOUSSTEP BUILDS ON PREVIOUS

• STRUCTURED ANALYSISSTRUCTURED ANALYSIS

• STRUCTURED DESIGNSTRUCTURED DESIGN

• STRUCTURED PROGRAMMINGSTRUCTURED PROGRAMMING

• FLOWCHARTSFLOWCHARTS

**

12.22

STRUCTURED ANALYSISSTRUCTURED ANALYSIS

• DEFINES SYSTEM INPUTS, PROCESSES, DEFINES SYSTEM INPUTS, PROCESSES, OUTPUTSOUTPUTS

• PARTITIONS SYSTEM INTO SUBSYSTEMS PARTITIONS SYSTEM INTO SUBSYSTEMS OR MODULESOR MODULES

• LOGICAL, GRAPHICAL MODEL OF LOGICAL, GRAPHICAL MODEL OF INFORMATION FLOWINFORMATION FLOW

• DATA FLOW DIAGRAM:DATA FLOW DIAGRAM: Graphical display Graphical display of component processes, flow of dataof component processes, flow of data

**12.23

SYMBOLS FOR DATA FLOW DIAGRAMS (DFD):SYMBOLS FOR DATA FLOW DIAGRAMS (DFD):

DATA FLOWDATA FLOW

PROCESSPROCESS

SOURCESOURCEOR SINKOR SINK

FILEFILE

12.24

GENERATE BILL

CUSTOMER

GENERATE BALANCE

GENERATE REPORT

MANAGER

PAYMENTFILE

CUSTOMERFILE

DATA FLOW DIAGRAM:DATA FLOW DIAGRAM:

12.25

STRUCTURED STRUCTURED ANALYSISANALYSIS

• DATA DICTIONARY:DATA DICTIONARY: Controlled definitions Controlled definitions of descriptions of all data, such as of descriptions of all data, such as variable names & types of datavariable names & types of data

• PROCESS SPECIFICATIONS:PROCESS SPECIFICATIONS: Describes Describes logic of processes at module level logic of processes at module level

**

12.26

STRUCTURED DESIGNSTRUCTURED DESIGN

DESIGN RULES / TECHNIQUES TO DESIGN DESIGN RULES / TECHNIQUES TO DESIGN SYSTEM, TOP DOWN IN HIERARCHICAL SYSTEM, TOP DOWN IN HIERARCHICAL

FASHIONFASHION• STRUCTURE CHARTSTRUCTURE CHART• STRUCTURED PROGRAMMINGSTRUCTURED PROGRAMMING• MODULEMODULE• SEQUENCE CONSTRUCTSEQUENCE CONSTRUCT• SELECTION CONSTRUCTSELECTION CONSTRUCT

**12.27

CALCULATE

GROSS PAY

CALCULATE

NET PAY

CALCULATE

PAY

PROCESS

PAYROLL

UPDATE

MASTER FILE

GET VALID

INPUTS

WRITE

OUTPUTS

GET

INPUTS

VALIDATE

INPUTS

WRITE

OUTPUTS

HIGH LEVEL STRUCTURE CHART:HIGH LEVEL STRUCTURE CHART:HIGH LEVEL STRUCTURE CHART:

(WHITE BOXES ARE MODULES)(WHITE BOXES ARE MODULES)12.28

STRUCTURED PROGRAMMING:STRUCTURED PROGRAMMING:

• DISCIPLINE TO ORGANIZE, CODE DISCIPLINE TO ORGANIZE, CODE PROGRAMSPROGRAMS

• SIMPLIFIES CONTROL PATHSSIMPLIFIES CONTROL PATHS

• EASY TO UNDERSTAND, MODIFYEASY TO UNDERSTAND, MODIFY

• MODULE HAS ONE INPUT, ONE MODULE HAS ONE INPUT, ONE OUTPUTOUTPUT

**

12.29

STRUCTURED PROGRAMMING:STRUCTURED PROGRAMMING:

• MODULE:MODULE: Logical unit of program. performs Logical unit of program. performs specific task(s)specific task(s)

• SEQUENCE CONSTRUCT:SEQUENCE CONSTRUCT: Sequential steps Sequential steps or actions in program logic; streamlines flowor actions in program logic; streamlines flow

• SELECTION CONSTRUCT:SELECTION CONSTRUCT: IF Condition R is IF Condition R is True THEN Action C ELSE Action DTrue THEN Action C ELSE Action D

• ITERATION CONSTRUCT:ITERATION CONSTRUCT: WHILE Condition WHILE Condition is True DO Action Eis True DO Action E

**

12.30

SYSTEM FLOWCHART SYMBOLS:SYSTEM FLOWCHART SYMBOLS:

12.31

DOCUMENT

DATABASE

ON-LINE DISPLAY TELECOMMUNICATIONS LINK

INPUT/OUTPUT PROCESS MAGNETIC TAPE

PUNCHED CARD MANUAL OPERATION ON-LINE STORAGE

ON-LINE INPUT

LOAD & VALIDATE

COMPARE & UPDATE

VALID TRANS-

ACTIONS

PAYROLL SYSTEM

TIME CARDS

HUMAN RESOURCES

DATA

PAYROLL MASTER

UPDATED PAYROLL

MASTER

DIRECT DEPOSITS

GENERAL LEDGER

PAYROLL REPORTS &

CHECKS

PAYROLL MASTER

12.32

SYSTEM FLOWCHART:SYSTEM FLOWCHART:

PROGRAM FLOWCHART PROGRAM FLOWCHART SYMBOLS:SYMBOLS:

BEGIN OREND

DIRECTION

PROCESS

DECISION

INPUT OROUTPUT

SUBROUTINE

MANUALOPERATION

CONNECTOR12.33

PROGRAM FLOWCHART:PROGRAM FLOWCHART:PROCESS A

PROCESS B

SEQUENCESEQUENCE

PROCESS CPROCESS D

R

TRUE

SELECTIONSELECTION

PROCESS E

S

TRUE

ITERATIONITERATION12.34

PROGRAM FLOWCHART:PROGRAM FLOWCHART:1

END

REPORT

MORE?2

PRINT

1

2START

READ

>$10,000

<$10,000

PROCESS A

PROCESS B

12.35

OBJECT - ORIENTED SOFTWARE OBJECT - ORIENTED SOFTWARE DEVELOPMENTDEVELOPMENT

• DE-EMPHASIZES PROCEDURESDE-EMPHASIZES PROCEDURES• SHIFTS FOCUS FROM MODELS & DATASHIFTS FOCUS FROM MODELS & DATA• TOTO OBJECTSOBJECTS, WHICH COMBINE DATA & , WHICH COMBINE DATA &

PROCEDURESPROCEDURES• OBJECTS REUSABLEOBJECTS REUSABLE• SYSTEM: Classes; objects; relationshipsSYSTEM: Classes; objects; relationships

REDUCES DEVELOPMENT TIME & COSTREDUCES DEVELOPMENT TIME & COST

**

12.36

COMPUTER AIDED SOFTWARE COMPUTER AIDED SOFTWARE ENGINEERING ENGINEERING (CASE)(CASE)

• AUTOMATION OF SOFTWARE AUTOMATION OF SOFTWARE METHODOLOGIESMETHODOLOGIES

• PRODUCES CHARTS; DIAGRAMS; PRODUCES CHARTS; DIAGRAMS; SCREEN & REPORT GENERATORS; SCREEN & REPORT GENERATORS; DATA DICTIONARIES; PROGRESS DATA DICTIONARIES; PROGRESS REPORTS; ANALYSIS; CHECKING REPORTS; ANALYSIS; CHECKING TOOLS; CODE; DOCUMENTATIONTOOLS; CODE; DOCUMENTATION

**

CASECASE12.37

COMPUTER AIDED SOFTWARE COMPUTER AIDED SOFTWARE ENGINEERING ENGINEERING (CASE)(CASE)

INCREASES PRODUCTIVITY & QUALITY:INCREASES PRODUCTIVITY & QUALITY:• ENFORCES DEVELOPMENT DISCIPLINEENFORCES DEVELOPMENT DISCIPLINE• IMPROVES COMMUNICATIONIMPROVES COMMUNICATION• DESIGN REPOSITORY FOR OBJECTSDESIGN REPOSITORY FOR OBJECTS• AUTOMATES TEDIOUS TASKSAUTOMATES TEDIOUS TASKS• AUTOMATES TESTING & CONTROLAUTOMATES TESTING & CONTROL• REQUIRES ORGANIZATIONAL DISCIPLINEREQUIRES ORGANIZATIONAL DISCIPLINE

**CASECASE12.38

SOFTWARE REENGINEERINGSOFTWARE REENGINEERING

• SALVAGES & UPGRADES AGING SALVAGES & UPGRADES AGING SOFTWARESOFTWARE

• DELAYS EXPENSIVE REPLACEMENTDELAYS EXPENSIVE REPLACEMENT• REVERSE ENGINEERING:REVERSE ENGINEERING: CONVERTING CONVERTING

EXISTING PROGRAMS, FILES, DATABASE EXISTING PROGRAMS, FILES, DATABASE FOR USE IN NEW APPLICATIONSFOR USE IN NEW APPLICATIONS

**12.39

SOFTWARE REENGINEERINGSOFTWARE REENGINEERING

• REVISE DESIGN & PROGRAM REVISE DESIGN & PROGRAM SPECIFICATIONSSPECIFICATIONS

• FORWARD ENGINEERING:FORWARD ENGINEERING: USE REVISED USE REVISED MATERIALS TO GENERATE NEW, MATERIALS TO GENERATE NEW, STRUCTURED CODE; STRUCTURED & STRUCTURED CODE; STRUCTURED & MAINTAINABLE SYSTEMMAINTAINABLE SYSTEM

**12.40

Connect to the INTERNETConnect to the INTERNET

PRESS LEFT MOUSE BUTTON ON ICON TO CONNECT TO THE LAUDON & LAUDON

WEB SITE FOR MORE INFORMATION ON THIS CHAPTER

12.41

12.42

DATA FLOW DIAGRAMDATA FLOW DIAGRAM::

GENERATE BILL

CUSTOMER

GENERATE BALANCE

GENERATE REPORT

MANAGER

PAYMENTFILE

CUSTOMERFILE