Download - System Development & Programming
Professor Michael J. LosaccoCIS 1110 – Using Computers
System Development & ProgrammingChapter 11
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Overview
Define System Development
List the System Development Phases
Explain Activities for Each Phase
Explain High- & Low-level Languages
Detail Steps of Program Development
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Information System
Hardware
Software
Data
People
Procedures
Together Produce Information
Interact to Achieve Common Goal
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System Development
Phases
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Guidelines
Arrange Tasks Into Phases
Groups of Activities
Involve Users
Anyone for Whom System is Being Built
Develop Clearly Defined Standards
Sets of Rules & Procedures
Company Expects Employees to Follow
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Initiation
Correct Problem in Existing System
Improve Existing System
Outside Group May Mandate Change
Competition Can Lead to Change
Request for System Services
AKA Project Request
Request for New / Modified System
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Participants
Representatives from Departments
Involved in Building or Using System
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Project Management
Project Manager
Plans, Schedules, & Controls Activities
Establishes Scope
Goals, Objectives, & Expectations of Project
List Required Activities
Time Required
Cost Estimate
Order & Dependency
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Project Success
SuccessfulOn-time, On-budget, All Features
ChallengedLate, Over Budget, Less Features
Failed Cancelled or Delivered but Never Used
Standish Group 2009
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Project Success
Smaller Projects Have Better Success
Standish Group
$10M+
$6-10M
$3-6M
$750K-3M
<$750K
0% 10% 20% 30% 40% 50% 60%
Success
Budg
et
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Project Success
Shorter Projects Have Better Success
Standish Group
6 9 12 18 240%
10%
20%
30%
40%
50%
60%
Months
Succ
ess
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Project Success
Average Percentage Above Estimate
Standish Group
1994 1996 1998 2000 2002 20040%
50%
100%
150%
200%
Time Cost
Year
Ove
rage
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Project Success
Notable Project FailuresFAA Air Traffic Control
$1.5B – 1994
IRS Modernization$3.4B – 1997
DoD Business Modernization$19B – 2004
200 Inventory / 450 Personnel Systems
Children’s Hospital of PittsburghDramatically Higher Death Rates – 2002
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Planning Phase
Steering Committee
Decision-making Body for Company
Receives Project Requests
Function of Committee:
Review & Approve Project
Prioritize Requests
Allocate Resources
Form Project Development Team
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Analysis Phase
Preliminary InvestigationDetermine Nature of Problem
Determine Whether it is Worth Pursuing
Feasibility Study
Economic
AKA Cost / Benefit
Operational
Schedule
Technical
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Analysis Phase
Detailed Analysis
Study How Current System Works
Determine User’s:
Wants
Needs
Recommend Solution
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Analysis Phase
Documentation
Collect & Summarize Data & Information
Reports
Diagrams
Programs
Other Deliverables
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Analysis Phase
Data & Information Gathering
Review Documentation
Research
Questionnaire
One-on-one interview
Observation
Joint-application Design (JAD) Session
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Analysis Phase
Process Modeling
AKA Structured Analysis & Design
Transform Inputs into Outputs
Entity-relationship Diagrams
Data Flow Diagrams
Project Dictionary
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Analysis Phase
Entity-relationship DiagramShows Connections Between Entities
EntitiesObjects in System that Have Data
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Analysis Phase
Data Flow Diagram
Shows Flow of Data in System
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Analysis Phase
Project Dictionary
Structured English
Used to Explain Details of Process
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Analysis Phase
Project Dictionary
Decision Table / Tree
Logical Conditions & Actions
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Analysis Phase
Project Dictionary
Data Dictionary
Stores Details About Each Data Item
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Analysis Phase
System Proposal
Assess Each Alternative Solution
Recommend Most Feasible Solution
Steering Committee Has to Approve
ROI
Hard v. Soft
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Analysis Phase
Possible SolutionsPackaged
Prewritten Software Available for PurchaseHorizontal
Meets Needs of Many Companies
Vertical
Designed for Specific Industry
CustomWrite Own Software
OutsourcingHire Outside Company to Perform Work
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Analysis Phase
OutsourcingSenior Resource Salaries
PayScale 2009
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Design Phase
Develop All Details of SystemWrite Technical Specifications
Details Functionality & Scope of Project
Request for Information (RFI)
Request for Quotation (RFQ)Vendor Quotes Price For Listed Hardware
Request for Proposal (RFP)Vendor Quotes Price For Software
Based on Specification
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Design Phase
Acquire Hardware & SoftwareSolicit / Test / Evaluate Vendor Proposals
References from Vendor
Talk to Current Users
Demonstrations
Trial Version
Benchmark Test Measures Performance
Prototype (Proof of Concept)
Working Model of Proposed System
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Design Phase
Acquire Hardware & Software
Turnkey Solution
Complete System Provided by VAR
Value-added Reseller
Purchases Products from Manufacturer
Resells Them, Offering Additional Services
Must Meet Certain Requirements
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Design Phase
Inspection
Step-by-step Review of Deliverables
By Project Team & Users
Uses
Final Review of Specification
Before Submitted to Programming Team
Identify & Correct Any Errors
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Implementation Phase
Build System & Deliver it to Users
Develop Programs
Test & Install
Train Users
Convert to New System
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Implementation Phase
Develop ProgramsProgrammers Write Code to Specification
Follow Program Development Life Cycle
Analyze the Requirements
Design the Solution
Validate the Design
Implement the Design
Test the Solution
Document the Solution
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Implementation Phase
TestingUnit
Each Individual Program Works
SystemAll Programs in Application Work Together
IntegrationApplication Works With Other Applications
AcceptanceVerifies New System Works with Actual Data
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Implementation Phase
TestingPhases
Alpha
Performed by Employees
Beta
Performed by Customers
TrainingShow Users How to Use New System
Scheduling Conflicts
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Implementation Phase
Convert to New System
Transition from Old to New System
Pilot Most Widely Used
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Support Phase
Ongoing Support After Implementation
Conduct Post-implementation Review
Perform Maintenance Activities
Identify & Correct Errors
Identify Enhancements
Monitor System Performance
Assess System Security
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Computer Program
Set of Instructions
Directs Computer to Perform Tasks
Language
Set of Words, Symbols, & Codes
Communicates Instructions to Computer
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Languages
CategoriesLow-level Languages
Machine Dependant
Typically Determined by Processor
Machine & Assembly
Faster Execution, More Code Required
High-level LanguagesMachine Independent
Third, & Fourth Generation
Slower Execution, Less Code Required
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Program Development
Development Options
Make (Create In-house)
More Control
Buy (Acquire from Software Vendor)
Lower Overall Cost
Higher Quality
Faster Implementation
Less Staff Required
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Analyze Requirements
Review Requirements
Meet with Systems Analyst & Users
Identify
Input
Processing
Output
Data
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Design Solution
Devise Solution Algorithm
Step-by-step Procedure to Solve Problem
Flowchart
Conveys Logic Graphically
Pseudocode
Uses Condensed English to Convey Logic
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Implement Design
Write Code
Translate Design into Program
Syntax
Rules that Specify How to Write Instructions
Comments
Program Documentation
Create User Interface
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Test Solution
Ensure Program Runs Correctly
Error Types
Syntax
Logic
Run time
Debugging
Locate & Correct Syntax & Logic Errors