System Development MIS Chapter 6 Jack G. Zheng May 28 th 2008.

System Development

MIS Chapter 6

Jack G. ZhengMay 28th 2008

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Overview

Systems Development Life Cycle

Prototyping

Outsourcing

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Systems Development Life Cycle (SDLC)

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SDLC Introduction

Systems Development Life Cycle is a process involving multiple stages (phases) to develop information systems

Each stage has specific goals, tasks and outputs

Good for task specialization

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SDLC Models

There are many models based on SDLC Different in the number of stages, stage

names and sequence

The original model, and the classic one, is the “waterfall” model (see the figure on the previous slide) Linear and sequential Each stage has clear goals and tasks

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Stage 1: Plan (Preliminary Investigation)

Goal To evaluate the need and feasibility of the system

Tasks Selecting and defining system

Identifying the need Setting system scope

High level definition of the system Be careful of scope creep – unable to control the boundary

of the system Developing project plan

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Stage 1: Plan (cont.)

Tasks (cont.) Developing project plan

Who: project manager develops and tracks the plan What: tasks, people, resources, and timeframes Project milestones describe date, activities and goals

for each stage

Output Whether or not to proceed

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Stage 2: Analysis

Goal To specify business requirements: detailed set of user

(organization) requests and needs

Tasks Gathering and documenting all business requirements

Who: business/system analysts How: Interview, observation, meeting

*Comparing initial solutions and choosing the best

Output Requirements definition document *Description of the recommended solution and basic

model (business model)

Difficult job

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Stage 3: Design (1)

Goal To build technical specifications and

solutions for the system

Tasks Designing technical architecture

Broad and basic technical framework including hardware, software, network and how they are integrated into a complete system

Designing system models

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Stage 3: Design (cont.)

Tasks (cont.) Designing system models (system/functional

modeling) System modeling is the process to transform

business requirements into technical models Interface design (GUI) Data modeling Business logic modeling

Output Detailed technical specifications and models

of the system

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Stage 4: Development

Goal To build the complete system

Tasks Building the platform/architecture

Setting up and configuring hardware and software for development

Building all parts of the system: GUI, database, business objects …

Actual coding by programmers

Output “Beta” version system

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Stage 5: Testing

Goal To verify the system meets all requirements and works

correctly and reliably (quality assurance)

Tasks Writing test conditions (test cases)

*Black-box testing By comparing the actual results and expected results

*White-box testing By analyzing the internal structure of the system

Performing testing System/functional testing: to verify the correctness and reliability User acceptance testing: to get user’s acceptance and satisfaction

Output Release version system

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Stage 6: Implementation (Deployment)

Goal To put the system in actual use

Tasks Deployment (how?)

One-time implementation Phased-in Parallel

Writing user documentation How-to manual for users (knowledge workers)

Training How: online (self-training); workshop

Output In-production system

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Stage 7: Maintenance

Goal To monitor, support and improve the system

Tasks Creating help desk (user support) Fixing errors and responding to changes

Configuring and modifying the system to meet changing needs

Identifying the need for better and newer system (back to stage 1)

Output Better systems or the need for new systems

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SDLC Phases Summary

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An Exercise

Scenario Professor Nickerson wanted to setup a website for his

E-Commerce Center. He asked John and Jenny to help him do the job. After 3 month work, the site is now established and is running well.

Task A set of related activities had happened for those 3

months (see the handout). These activities are in random order. Please link them correctly to each SDLC stage.

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Variance of SDLC

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Prototyping

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Prototyping

Prototyping is the process of developing systems using prototypes

Prototype A scaled-down but working version of a

desired system (or part of a system) It demonstrates major features, functions and

feel of the system But it does not have all the functions and it is

buggy

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Prototyping Process

A rapid but iterative process

Figure 6.6 on page 292

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What Are Prototypes Used For?

Gathering and determining requirements It is easier for users to articulate their needs if they

have a direct feel of system

Proof-of-concept Can it be done? Let’s use a prototype to analyze the

feasibility of the system.

Selling the idea You don’t see the benefit? Let the prototype show

you.

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Pros and Cons of Prototyping

Advantages Encourages user participation and helps elaborate

user requirements Gives a feel for the final system Helps determine technical feasibility (proof-of-concept

prototype) and sell the idea (selling prototype)

Disadvantages Leads people to believe the final system will finish

shortly Gives no indication of performance under operational

conditions Leads developers to skip proper testing and

documentation

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Outsourcing

Outsourcing The delegation of business process (administrative,

engineering, research, development, or technical support) to other organizations

Example: www.borders.com

Off-shoring The migration of part or all of the business processes

to another country

Off-shore outsourcing … to other organizations in another country

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Forms of IT Outsourcing

Figure 6.7 on page 295

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Pros and Cons of IT Outsourcing

Why to outsource? Reduce development costs Focus on business core competencies Gain best practices and capabilities …

Disadvantages Difficult to assimilate knowledge for future innovation Vulnerability of business secret Dependency on other organizations …

What are the impacts of IT off-shoring/outsourcing on employees, companies, industries and nations?

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Good Resources

Government Accountability Office (GAO) reports http://www.gao.gov/docsearch/topic.php

How to Write a Request for Proposal for a Web Project http://www.webdevelopersjournal.com/columns/writerfp.html

Software Engineering Institute http://www.sei.cmu.edu/

CIO.com outsourcing http://www.cio.com/research/outsourcing/