Transcript THE INFORMATION AGE IN WHICH YOU LIVE Changing the …
Lecture 9 SYSTEMS DEVELOPMENT Phases, Tools, and Techniques
1
STUDENT LEARNING OUTCOMES
1.
2.
3.
Define the traditional systems development life cycle (SDLC) and describe the 7 major phases within it.
Compare and contrast the various component based development methodologies.
Describe the self-sourcing process as an alternative to the traditional SDLC.
2
STUDENT LEARNING OUTCOMES
4.
5.
Discuss the importance of prototyping and prototyping within any systems development methodology Describe the outsourcing environment and how outsourcing works.
3
SAVING LIVES THROUGH SYSTEMS DEVELOPMENT
o Centers for Disease Control (CDC) tracks a wealth of information – – Antimicrobial-resistant infections in hospitals Influenza outbreaks – – Terrorist biochemical attacks Bacteria counts in rivers and stagnant ponds, etc o Unfortunately, most of that information is stored in separate IT systems that do not communicate with each other
4
SAVING LIVES THROUGH SYSTEMS DEVELOPMENT
o The CDC is using a service-oriented architecture (SoA) to integrate all those systems and information o An SoA treats every component of an IT system – a database file, a server, a CRM software solution, etc – as a building block o Within an SoA, those building blocks can be “plugged and played” so that everything works together in an integrated fashion
5
SAVING LIVES THROUGH SYSTEMS DEVELOPMENT
1.
2.
3.
All computers use a common binary base language. That being true, why is it so difficult to get computer systems to easily communicate with each other?
In systems development, prototyping is used to build a model of a proposed system. How have you used prototyping in your personal life?
Outsourcing – going to another company for systems development – is big business. Why would the CDC
not want
to pursue outsourcing?
6
INTRODUCTION
o Information systems are the support structure for meeting the company’s strategies and goals o New systems are created because employees request them o New systems are created to obtain a competitive advantage
7
INTRODUCTION
o When developing a new system, you have 3 “who” choices…
1.
Insourcing
– IT specialists inside your organization
2.
3.
Selfsourcing
– do-it-yourself approach many end users take with little or no help from IT specialists
Outsourcing
– a third-party organization (i.e., let someone do the work and pay them for it)
8
INSOURCING AND THE SDLC
o
Systems development life cycle (SDLC)
- a structured step-by-step approach for developing information systems o 7 distinct phases, each with well-defined activities o Also called a
waterfall methodology
, an approach in which each phase of the SDLC is followed by another, from planning through implementation
9
SDLC Phases & Major Activities
10
SDLC as a Waterfall Methodology
11
Phase 1: Planning
o o
Planning phase
- create a solid plan for developing your information system Three primary planning activities: 1.
• • Define the system to be developed You can’t build every system, so you make choices based on your organization’s priorities, which may be expressed as critical success factors
Critical success factor (CSF)
your organization’s success - a factor simply critical to
12
Phase 1: Planning
2.
• • • • Set the project scope
Project scope -
clearly defines the high-level system requirements
Scope creep -
occurs when the scope of the project increases
Feature creep -
occurs when developers add extra features that were not part of the initial requirements
Project scope document -
a written definition of the project scope and is usually no longer than a paragraph
13
Phase 1: Planning
3.
• • • Develop the project plan including tasks, resources, and timeframes
Project plan
- defines the what, when, and who questions of system development
Project manager -
an individual who is an expert in project planning and management, defines and develops the project plan and tracks the plan to ensure all key project milestones are completed on time
Project milestones
- represent key dates for which you need a certain group of activities performed
14
Phase 1: Planning
Sample Project Plan
15
Phase 2: Analysis
o
Analysis phase -
involves end users and IT specialists working together to gather, understand, and document the business requirements for the proposed system
16
Phase 2: Analysis
o Two primary analysis activities: 1.
• • • Gather the business requirements
Business requirements
- the detailed set of knowledge worker requests that the system must meet in order to be successful Business requirements address the “why” and “what” of your development activities
Joint application development
(
JAD
) - knowledge workers and IT specialists meet, sometimes for several days, to define or review the business requirements for the system
17
Phase 2: Analysis
2.
• • • Prioritize the requirements
Requirements definition document –
prioritizes the business requirements and places them in a formal comprehensive document Again, you probably can’t do everything, so prioritizing is important Users sign off on this document which clearly sets the scope for the project
18
Phase 2: Analysis
Take time during analysis to get the business requirements correct. If you find errors, fix them immediately. The cost to fix an error in the early stages of the SDLC is relatively small. In later stages, the cost is huge.
19
Phase 3: Design
o o
Design phase
- build a technical blueprint of how the proposed system will work Two primary design activities: 1.
• Design the technical architecture
Technical architecture -
defines the hardware, software, and telecommunications equipment required to run the system
20
Phase 3: Design
2.
• Design system models This includes GUI screens that users will interface with, database designs , report formats, software steps, etc o Starting with design, you take on less of an active participation role and act more as a “quality control” function, ensuring that the IT people are designing a system to meet your needs
21
Phase 4: Development
o o
Development phase -
take all of your detailed design documents from the design phase and transform them into an actual system 1.
Two primary development activities: Build the technical architecture 2.
• Build the database and programs Both of these activities are mostly performed by IT specialists
22
Phase 5: Testing
o o
Testing phase
- verifies that the system works and meets all of the business requirements defined in the analysis phase Two primary testing activities: 1.
• Write the test conditions
Test conditions
- the detailed steps the system must perform along with the expected results of each step
23
Phase 5: Testing
2.
• • • • Perform the testing of the system
Unit testing
– tests individual units of code
System testing
– verifies that the units of code function correctly when integrated
Integration testing
work together – verifies that separate systems
User acceptance testing (UAT)
– determines if the system satisfies the business requirements
24
Phase 6: Implementation
o o
Implementation phase -
distribute the system to all of the knowledge workers and they begin using the system to perform their everyday jobs Two primary implementation activities 1.
• Write detailed user documentation
User documentation
- highlights how to use the system
25
Phase 6: Implementation
2.
• • Provide training for the system users
Online training
- runs over the Internet or off a CD-ROM
Workshop training -
is held in a classroom environment and lead by an instructor
26
Phase 6: Implementation
o Choose the right implementation method –
Parallel implementation
– use both the old and new system simultaneously – – –
Plunge implementation
– discard the old system completely and use the new
Pilot implementation
– start with small groups of people on the new system and gradually add more users
Phased implementation
– implement the new system in phases
27
Phase 7: Maintenance
o o
Maintenance phase
- monitor and support the new system to ensure it continues to meet the business goals Two primary maintenance activities: 1.
• Build a help desk to support the system users
Help desk
- a group of people who responds to knowledge workers’ questions 2.
Provide an environment to support system changes
28
COMPONENT-BASED DEVELOPMENT
o o The SDLC focuses only on the project at hand
Component-based development (CBD)
– focuses on building small self-contained blocks of code (components) that can be reused across a variety of applications o CBD focuses on 1.
2.
Using already-developed components to build systems quickly Building new components as needed that can be used in all future systems
29
Component-Based Development Methodologies
o Rapid application development (RAD) o Extreme programming (XP) o Agile methodology
30
Rapid Application Development (RAD)
o
Rapid application development (RAD)
(also called
rapid prototyping
) - emphasizes extensive user involvement in the rapid and evolutionary construction of working prototypes of a system to accelerate the systems development process o Prototypes are models of the software components o The development team continually designs, develops, and tests the component prototypes until they are finished
31
Rapid Application Development (RAD)
Build new software components Use already existing software components
32
Extreme Programming (XP)
o
Extreme programming (XP) -
breaks a project into tiny phases and developers cannot continue on to the next phase until the first phase is complete
33
Agile Methodology
o
Agile methodology -
a form of XP, aims for customer satisfaction through early and continuous delivery of useful software components
34
SoA – An Architecture Perspective
o
Service-oriented architecture (SoA)
– perspective that focuses on the development, use, and reuse of small self-contained blocks of code (called
services
) to meet all application software needs o All CBD methodologies adhere to an SoA o
Services
are the same as
components
, which are the same as small self-contained blocks of code o More in Lecture 7
35
SELFSOURCING
o o o
Selfsourcing (end-user development)
– the development and support of IT systems by end users with little or no help from IT specialists Do-it-yourself systems development approach Can relieve IT specialists of the burden of developing many smaller systems
36
Selfsourcing Approach
o Is similar to traditional SDLC o Big exception is that design, development, testing, and implementation are replaced by the process of prototyping o Prototyping is the process of building models, and – in this case – continually refining those models until they become the final system
37
Selfsourcing Approach
38
Selfsourcing Advantages
o Improves requirements determination o Increases end user participation and sense of ownership o Increases speed of systems development o Reduces invisible backlog –
Invisible backlog
– list of all systems that an organization needs to develop but – because of the prioritization of systems development needs – never get funded because of the lack of organizational resources
39
Selfsourcing Disadvantages
o Inadequate end user expertise leads to inadequately developed systems o Lack of organizational focus creates “privatized” IT systems o Insufficient analysis of design alternatives leads to subpar IT systems o Lack of documentation and external support leads to short-lived systems
40
The Right Tool for the Job
o End users must have development tools that: – Are easy to use – – – Support multiple platforms Offer low cost of ownership Support a wide range of data types
41
PROTOTYPING
o
Prototype
– a model of a proposed product, service, or system o
Prototyping
- the process of building a model that demonstrates the features of a proposed product, service, or system –
Proof-of-concept prototype -
used to prove the technical feasibility of a proposed system –
Selling prototype
- used to convince people of the worth of a proposed system
42
The Prototyping Process
o 1.
The prototyping process involves four steps: Identify basic requirements 2.
3.
4.
Develop initial prototype User review Revise and enhance the prototype
43
The Prototyping Process
44
Advantages of Prototyping
o Encourages active user participation o Helps resolve discrepancies among users o Gives users a feel for the final system o Helps determine technical feasibility o Helps sell the idea of a proposed system
45
Disadvantages of Prototyping
o Leads people to believe the final system will follow o Gives no indication of performance under operational conditions o Leads the project team to forgo proper testing and documentation
46
OUTSOURCING
o o
Outsourcing
– the delegation of specified work to a third party for a specified length of time, at a specified cost, and at a specified level of service The third “who” option of systems development, after insourcing and selfsourcing
47
OUTSOURCING
o The main reasons behind the rapid growth of the outsourcing industry include the following: – Globalization – – – – The Internet Growing economy and low unemployment rate Technology Deregulation
48
Outsourcing Options
o 1.
IT outsourcing for software development can take one of four forms: Purchase existing software 2.
3.
4.
Purchase existing software and pay the publisher to make certain modifications Purchase existing software and pay the publisher for the right to make modifications yourself Outsource the development of an entirely new and unique system for which no software exists
49
Outsourcing Options
50
Outsourcing Process
o o Like selfsourcing, the selfsourcing process looks similar to the traditional SDLC Big exception here is that you “outsource” most of the work to another company
51
Outsourcing Process
When outsourcing, you’ll develop two vitally important documents – a request for proposal and a service level agreement
52
Outsourcing – RFP
o
Request for proposal (RFP)
– formal document that describes in excruciating detail your logical requirements for a proposed system and invites outsourcing organizations (vendors) to submit bids for its development o In outsourcing, you must tell another organization what you want developed; you do that with an RFP o Therefore, the RFP must be very detailed and complete o Some RFPs can take months or even years to develop
53
Outsourcing – SLA
o
Service level agreement (SLA)
- formal contractually obligated agreement between two parties o o In outsourcing, it is the legal agreement between you and the vendor and specifically identifies what the vendor is going to do (and by when) and how much you’re going to pay Supporting SLA documents –
specifications service level
and
service level objectives
– contain very detailed numbers and metrics
54
Outsourcing Options
o
1.
2.
3.
There are three different forms of outsourcing:
Onshore outsourcing
- the process of engaging another company within the same country for services
Nearshore outsourcing
- contracting an outsourcing arrangement with a company in a nearby country
Offshore outsourcing
- contracting with a company that is geographically far away
55
Offshore Outsourcing
o Primary outsourcing countries are: – India – – – – – China Eastern Europe (including Russia) Ireland Israel Philippines
56
The Advantages and Disadvantages of Outsourcing
o Advantages: – Focus on unique core competencies – – – – – Exploit the intellect of another organization Better predict future costs Acquire leading-edge technology Reduce costs Improve performance accountability
57
The Advantages and Disadvantages of Outsourcing
o Disadvantages: – Reduces technical know-how for future innovation – – – Reduces degree of control Increases vulnerability of your strategic information Increases dependency on other organizations
58
End of Lecture
59