System lifecycle

12.1

DATA FLOW DIAGRAMDATA FLOW DIAGRAM::

GENERATE BILL

CUSTOMER

GENERATE BALANCE

GENERATE REPORT

MANAGER

PAYMENTFILE

CUSTOMERFILE

CONTENTSCONTENTS

• TRADITIONAL SYSTEMS LIFECYCLETRADITIONAL SYSTEMS LIFECYCLE

• ALTERNATIVE SYSTEM-BUILDING ALTERNATIVE SYSTEM-BUILDING APPROACHESAPPROACHES

**

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 (manual or automated); existing systems (manual or automated); define objectives; evaluate alternativesdefine objectives; evaluate 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: Test, train, convert to new Test, train, convert to new systemsystem

• POST-IMPLEMENTATION:POST-IMPLEMENTATION: 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 & PROJECTS (TPS AND MIS)SYSTEMS & PROJECTS (TPS AND MIS)

**

12.5


LIMITATIONS:LIMITATIONS:

• CAN BE COSTLY, TIME CONSUMING, CAN BE COSTLY, TIME CONSUMING, INFLEXIBLEINFLEXIBLE

• MAY ENCOURAGE FREEZING MAY ENCOURAGE FREEZING SPECIFICATIONS EARLY IN DEVELOPMENTSPECIFICATIONS EARLY IN DEVELOPMENT

• MAY NOT BE SUITABLE FOR DSS OR MAY NOT BE SUITABLE FOR DSS OR SMALL, LESS STRUCTURED SYSTEMSSMALL, LESS 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 INITIAL PROTOTYPE2. DEVELOP INITIAL 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 THAT IS COMMERCIALLY SOFTWARE THAT IS COMMERCIALLY AVAILABLE FOR SALE OR LEASEAVAILABLE FOR SALE OR LEASE

• GEARED TO COMMON REQUIREMENTSGEARED TO COMMON REQUIREMENTS

**

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 OF WITHOUT DESTROYING INTEGRITY OF PACKAGEPACKAGE

• RAISES DEVELOPMENT COSTSRAISES DEVELOPMENT COSTS• MUST WEIGH COSTS / BENEFITSMUST WEIGH COSTS / BENEFITS

**12.12

0

2

4

6

8

10

0.5 1 2 3 4 5

% LINES OF CODE CONVERTED% LINES OF CODE CONVERTED

TO

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IMP

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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

LIMIT LOGIC & LIMIT 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


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

DEVELOPING APPLICATION (e.g. Payroll)DEVELOPING APPLICATION (e.g. Payroll)• PREDICTABILITY OF UNINTERRUPTED PREDICTABILITY OF UNINTERRUPTED

SERVICE NOT IMPORTANTSERVICE NOT IMPORTANT(e.g. travel expense(e.g. travel expenseprocessing)processing)

**

12.20


WHEN TO OUTSOURCE:WHEN TO OUTSOURCE:• IF EXISTING SYSTEM IS LIMITED, IF EXISTING SYSTEM IS LIMITED,

INEFFECTIVE, INFERIORINEFFECTIVE, INFERIOR• TO IMPROVE THE CONTRIBUTION OF IT TO IMPROVE THE CONTRIBUTION OF IT

TO BUSINESS TO BUSINESS PERFORMANCEPERFORMANCE

**

12.20

12.42

DATA FLOW DIAGRAMDATA FLOW DIAGRAM::

GENERATE BILL

CUSTOMER

GENERATE BALANCE

GENERATE REPORT

MANAGER

PAYMENTFILE

CUSTOMERFILE