System Development MIS Chapter 6 Jack G. Zheng July 18 th 2005.
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Transcript of System Development MIS Chapter 6 Jack G. Zheng July 18 th 2005.
System Development
MIS Chapter 6
Jack G. ZhengJuly 18th 2005
2
Overview
Systems Development Life Cycle
Prototyping
Outsourcing
3
Opening Case
Classic IT project failure: Denver International Airport (DIA) automated baggage handling system
Some facts DIA is a huge airport that spans about 53 square
miles (size of San Francisco), with a total cost of over 4.8 billion
The airport delayed opening for 16 months, because of the baggage system
The automated baggage system was finally abandoned after 3 years’ development and almost 500 million over budget
4
Systems Development Life Cycle (SDLC)
5
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
6
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
7
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
8
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
9
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
10
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
11
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
12
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
13
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
14
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
15
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
16
SDLC Phases Summary
17
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.
18
Variance of SDLC
19
Prototyping
20
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
21
Prototyping Process
A rapid but iterative process
Figure 6.6 on page 292
22
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.
23
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
24
IT Outsourcing
25
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
26
Forms of IT Outsourcing
Figure 6.7 on page 295
27
IT Outsourcing Process
Request for Proposal (RFP)
28
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?
29
Summary
7 stages of SDLC Understand the goal, tasks, output
Prototyping is rapid and iterative way to develop system
IT outsourcing
30
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/