solving problems in is: systems approaches logical framework in which to work. logical framework in...
Post on 21-Dec-2015
213 views
TRANSCRIPT
Solving Problems in IS: Systems Solving Problems in IS: Systems ApproachesApproaches
• Logical framework in which to work.Logical framework in which to work.• Serves as a reminder. Did I forget Serves as a reminder. Did I forget
anything?anything?
The Systems Development Life Cycle, “SDLC”
Planning
Analysis
Design
Implementation
The Systems Development Life Cycle, “SDLC”
Planning
Analysis
Design
Implementation
Maintenance!
The Systems Development Life CycleThe Systems Development Life Cycle
Systems ImplementationProduct:
Operational System
Systems ImplementationProduct:
Operational System
Systems InvestigationProduct:
Feasibility Study
Systems InvestigationProduct:
Feasibility Study
Systems AnalysisProduct:
Functional Requirements
Systems AnalysisProduct:
Functional Requirements
Systems DesignProduct:
System Specifications
Systems DesignProduct:
System Specifications
Systems MaintenanceProduct:
Improved System
Systems MaintenanceProduct:
Improved System
Understand theBusinessProblem orOpportunity
Develop anInformationSystemSolution
ImplementtheSystemSolution
(Dennis text:4 phases, with“Investigation”named “Planning”)
Planning
Analysis
Design
Implementation
Identify Problem/Value.Feasibility Analysis.Project Management.
Understand as-is system.Identify Improvements.Develop concept forthe to-be system.Use Cases.DFDs.ERDs.
Develop technicalspecifics for to-besystem.Design Strategies.Physical DFD.Physical ERD.Infrastructure Plan.Interface Structure.Interface Standards.Interface Template.Interface.Evaluate.
SDLCSDLC
Construction (programming)TestingDocumentationConversionChange ManagementSupportInstallation
• 2-4 times over budget.2-4 times over budget.• 2-3 times behind schedule.2-3 times behind schedule.• Not performing as expected.Not performing as expected.• Complicated to use.Complicated to use.• Requires more and more users to operate.Requires more and more users to operate.• Loses or destroys data.Loses or destroys data.
Watch out for “runaway Watch out for “runaway computer systems”!computer systems”!
30-35% of 30-35% of computer projects computer projects
are runaways!are runaways!(Dennis text: 42% of all corporateProjects are abandoned)
Where can we spot one?Where can we spot one?
Planning
Analysis
Design
Implementation
Maintenance
Where can we spot one?Where can we spot one?
Analysis
Design
Implementation
Maintenance
On time?Budget?
Planning
Where can we spot one?Where can we spot one?
Analysis
Design
Implementation
Maintenance
On time?Budget?
Performing asexpected?What do theusers think?
Planning
How can we prevent runaways?How can we prevent runaways?
Analysis
Design
Implementation
Maintenance
Planning
How can we prevent runaways?How can we prevent runaways?
Analysis
Design
Implementation
Maintenance
“The numberone cause ofrunaways isthe installationor expansionof a computersystem whenmanagementdoes not knowwhat theautomation ismeant to accomplish.”
Planning
How can we prevent runaways?How can we prevent runaways?
Analysis
Design
Implementation
Maintenance
“The numberone cause ofrunaways isthe installationor expansionof a computersystem whenmanagementdoes not knowwhat theautomation ismeant to accomplish.”
Involve bothmanagementand users inspecifying whatthe system needsto accomplish.
Continuously talkto and monitor thedesign team. BUT,don’t use them asyour only source ofinformation!
Planning
How can we prevent runaways?How can we prevent runaways?
Analysis
Design
Implementation
Maintenance
Involve bothmanagementand users inspecifying whatthe system needsto accomplish.
Continuously talkto and monitor thedesign team. BUT,don’t use them asyour only source ofinformation!
Test early andoften!
Watch to makesure things aregoing smoothly.
Planning
CONFIRM: A classic runaway CONFIRM: A classic runaway example.example.
• AMR partnered with Budget, Hilton, and Marriott AMR partnered with Budget, Hilton, and Marriott to leverage the success of SABRE, American’s to leverage the success of SABRE, American’s reservation system.reservation system.
• SABRE auditors, two months before the project SABRE auditors, two months before the project was supposed to go on-line, concluded that the was supposed to go on-line, concluded that the project was at least 18 months from completion.project was at least 18 months from completion.
• Budgeted at around $125 Million... around $225 Budgeted at around $125 Million... around $225 Million shelled out with no result.Million shelled out with no result.
Where did CONFIRM go wrong?Where did CONFIRM go wrong?AMR’s answer:AMR’s answer:
Analysis
Design
Implementation
Maintenance
Planning
Where did CONFIRM go wrong?Where did CONFIRM go wrong?AMR’s answer:AMR’s answer:
Analysis
Design
Implementation
Maintenance
Budget, Hilton,and Marriottassignedindividuals who“lacked knowledge ofthe industry”.
Planning
Where did CONFIRM go wrong?Where did CONFIRM go wrong?AMR’s answer:AMR’s answer:
Analysis
Design
Implementation
Maintenance
Budget, Hilton,and Marriottassignedindividuals who“lacked knowledge ofthe industry”.
These individualsfailed to specifywhat they wantedfrom the system.
Planning
Where did CONFIRM go wrong?Where did CONFIRM go wrong?Budget, Hilton, and Marriott’s answer:Budget, Hilton, and Marriott’s answer:
Analysis
Design
Implementation
Maintenance
Planning
Where did CONFIRM go wrong?Where did CONFIRM go wrong?Budget, Hilton, and Marriott’s answer:Budget, Hilton, and Marriott’s answer:
Analysis
Design
Implementation
Maintenance
“You said SABREexperts wouldbe assigned to thisproject... where arethey?!”
Schedules overlyoptimistic.
TECHNICALPROBLEMS!!The two 3090sdidn’t connectwell.
Planning
Where did CONFIRM go wrong?Where did CONFIRM go wrong?Budget, Hilton, and Marriott’s answer:Budget, Hilton, and Marriott’s answer:
Analysis
Design
Implementation
Maintenance
“You said SABREexperts wouldbe assigned to thisproject... where arethey?!”
Schedules overlyoptimistic.
Endless delays.Cost overruns.PROBLEMSCONCEALED!
“We GAVE youspecs... 6 feethigh!”
Planning
Software Development...Software Development...
• ... is hard!... is hard!• Windows 95:Windows 95:
• 400 people400 people• 4 years4 years– $100,000,000$100,000,000– 10,000,000 lines of code10,000,000 lines of code– 1 “person meeting” per line of code1 “person meeting” per line of code
• Studies have indicated that an experienced Studies have indicated that an experienced programmer can produce 30 lines of code per day programmer can produce 30 lines of code per day on average.on average.
• A new billing system can easily require 1 million A new billing system can easily require 1 million lines of code.lines of code.
• That’s 33,000 days, or 133 years, for one That’s 33,000 days, or 133 years, for one programmer! Coordinating multiple programmers programmer! Coordinating multiple programmers makes the job more complex.makes the job more complex.
• Annual software productivity increases - about 4% Annual software productivity increases - about 4% per year (vs. 30% in hardware).per year (vs. 30% in hardware).
The IS Project “Logjam”The IS Project “Logjam”• Two years planned to put “water” and Two years planned to put “water” and
“electricity” on the same bill. 40 man-years “electricity” on the same bill. 40 man-years and $2 million later, no results!and $2 million later, no results!
• Why is software development so difficult?Why is software development so difficult?
The IS Project “Logjam”The IS Project “Logjam”• Government study: two-thirds of software Government study: two-thirds of software
projects had no formal procedure for estimating projects had no formal procedure for estimating the amount of labor or code required, and nearly the amount of labor or code required, and nearly half had no standard way to predict the cost of a half had no standard way to predict the cost of a program.program.
• Late additions and maintenance - 80% of software Late additions and maintenance - 80% of software budgets.budgets.
• Twice the time expected, twice the money - Twice the time expected, twice the money - “runaway”. As noted, 30-35% of companies fall “runaway”. As noted, 30-35% of companies fall victim to them.victim to them.
Breaking the IS Project Logjam - Breaking the IS Project Logjam - “Solution”“Solution”
• Give data-processing departments the same clout as Give data-processing departments the same clout as everybody else.everybody else.
• Keep both managers and ultimate users involved in Keep both managers and ultimate users involved in every step of software development.every step of software development.
• Make data-processing managers periodically work Make data-processing managers periodically work side by side with software users.side by side with software users.
• Break up big projects to keep programming teams Break up big projects to keep programming teams small.small.
• Give programmers elbowroom.Give programmers elbowroom.• Make existing software easier to maintain.Make existing software easier to maintain.
Have competent Project Have competent Project Managers and Analysts!!!!Managers and Analysts!!!!
Development MethodologiesDevelopment Methodologies• Traditional (structured):Traditional (structured):
• Waterfall - sequential through steps.Waterfall - sequential through steps.• Parallel - sequential through steps, with “Design” often Parallel - sequential through steps, with “Design” often
being done in multiple simultaneous subprojects.being done in multiple simultaneous subprojects.• Rapid Application Development (RAD):Rapid Application Development (RAD):
• Phased - system broken into “versions”, steps are Phased - system broken into “versions”, steps are completed for each version and repeated for next version.completed for each version and repeated for next version.
• Prototyping - “quick and dirty” through Analysis, Design, Prototyping - “quick and dirty” through Analysis, Design, and Implementation in iterative fashion.and Implementation in iterative fashion.
• Throwaway Prototyping - same as above except Throwaway Prototyping - same as above except prototypes are “pretend”.prototypes are “pretend”.
Waterfall Development MethodWaterfall Development Method
Pros and Cons of the Waterfall Pros and Cons of the Waterfall MethodMethod
Pros Cons
Identifies systems requirements long before programming begins
Design must be specified on paper before programming begins
Long time between system proposal and delivery of new system
Parallel Development MethodParallel Development Method
Pros and Cons of Parallel Pros and Cons of Parallel DevelopmentDevelopment
Pros Cons
Reduces Scheduled Time
Less Chance ofRework
Still Uses PaperDocuments
Sub-projects May BeDifficult to Integrate
How Prototyping WorksHow Prototyping Works
Throwaway PrototypingThrowaway Prototyping
Pros and Cons of PrototypingPros and Cons of Prototyping
Pros Cons
Very quickly produces a system
Increased and Quicker userinteraction
Less disciplined - Often sloppy
Initially intelligentdesign features
Become problems
Picking the right methodologyPicking the right methodology
Ability to Develop Systems Waterfall Parallel Phased Prototyping ThrowawayWith unclear user requirements Poor Poor Good Excellent ExcellentWith unfamiliar technology Poor Poor Good Poor ExcellentThat are complex Good Good Good Poor ExcellentThat are reliable Good Good Good Poor ExcellentWith a short time schedule Poor Good Excellent Excellent GoodWith schedule visibility Poor Poor Excellent Excellent Good
Structured Methodologies RAD Methodologies