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