system development life cycle SDLC

System Development Life Cycle (SDLC)
by
ANEESH.S

System Development Life Cycle (SDLC)
1. System Development Life Cycle (SDLC) is a series
of six main phases to create a hardware system
only, a software system only or a combination of
both to meet or exceed customer’s expectations.

The System Development Life Cycle
What is an information system (IS)?
Hardware, software, data,
people, and procedures that
work together to produce
quality information
Hardware, software, data,
people, and procedures that
work together to produce
quality information
System—Set of components
that interact to achieve
common goal
System—Set of components
that interact to achieve
common goal
Businesses use many types of
systems
Businesses use many types of
systems

What are the phases of the system development cycle?
Phase 1. Planning
Phase 2. Analysis
Phase 3. Design
Phase 4. ImplementationPhase 5. Support
 Review project requests
 Prioritize project
requests
 Allocate resources
 Identify project
development team
 Conduct preliminary investigation
 Perform detailed analysis activities:
Study current system
Determine user requirements
Recommend solution
 Acquire hardware
and software, if
necessary
 Develop details of
system
 Develop programs, if necessary
 Install and test new system
 Train users
 Convert to new system
 Conduct post-implementation
system review
 Identify errors and enhancements
 Monitor system performance

Arrange tasks into phases
(groups of activities)
What are guidelines for system development?
Involve users (anyone for whom
system is being built)
Develop clearly defined standards (procedures
company expects employees to follow)

Who participates
in the system
development life
cycle?

What is a systems analyst?
Responsible for designingResponsible for designing
and developingand developing
information systeminformation system
Liaison between usersLiaison between users
and IT professionalsand IT professionals

What is the project team?
Consists of users, systems analyst, and other IT professionals
Formed to work on project from beginning to end
Project leader—one member of the team who
manages and controls project budget and schedule

What is feasibility?
Measure of
how suitable
system
development
will be to the
company
Operational
feasibility
Schedule
feasibility
Four feasibility
tests:
Technical
feasibility
Economic
feasibility
(also called
cost/benefit
feasibility)

What is documentation?
Includes reports, diagrams,
programs, and other deliverables
Collection and summarization
of data and information

What are six data and information gathering techniques?
 Review documentation
 Observe
 Questionnaire
 Interview
 Joint-application
design (JAD) session
 Research

What are some reasons to create or modify an
information system?
Competition can
lead to change
To improve
existing system
Outside group may
mandate change
To correct problem
in existing system

What is a request for system services?
 Formal request for
new or modified
information system
 Also called
project request

What is the planning phase?
Begins when steering committee receives project request
SteeringSteering
committeecommittee——
decision-makingdecision-making
body for thebody for the
companycompany
Function of committee:
Review andReview and
approve projectapprove project
requestsrequests
AllocateAllocate
resourcesresources
Form projectForm project
developmentdevelopment
team for eachteam for each
approvedapproved
projectproject
PrioritizePrioritize
project requestsproject requests

What is the analysis phase?
Conduct preliminaryConduct preliminary
investigation, alsoinvestigation, also
called feasibilitycalled feasibility
studystudy
Perform detailedPerform detailed
analysisanalysis

What is the preliminary investigation?
 Determine exact nature of problem or improvement
and whether it is worth pursuing
 Findings are presented in feasibility report, also known as a feasibility study

What is detailed analysis?
Sometimes called logical design
2. Determine user’s wants, needs,
and requirements
3. Recommend solution
1. Study how current system
works

Presented toPresented to
steeringsteering
committee,committee,
which decideswhich decides
how system willhow system will
be developedbe developed
What is the
system proposal? AssessesAssesses
feasibilityfeasibility
of eachof each
alternativealternative
solutionsolution
RecommendsRecommends
the mostthe most
feasiblefeasible
solution forsolution for
the projectthe project

What are possible solutions?
Buy packaged software—prewritten
software available for purchase
Buy packaged software—prewritten
software available for purchase
Outsource—have outside source
develop software
Outsource—have outside source
develop software
Write own custom software—software
developed at user’s request
Write own custom software—software
developed at user’s request
Vertical market
software—designed
for particular industry
Vertical market
software—designed
for particular industry
Horizontal market
software—meets
needs of many
companies
Horizontal market
software—meets
needs of many
companies

What is the design phase?
Acquire hardware and softwareAcquire hardware and software
Develop all details of new or
modified information system
Develop all details of new or
modified information system

Visit vendors’ storesVisit vendors’ storesVisit vendors’ storesVisit vendors’ stores
What is needed to acquire new hardware and software?
 Identify all hardware and software requirements of new or
modified system
Surf WebSurf WebSurf WebSurf Web
Read print andRead print and
online trade journals,online trade journals,
newspapers, andnewspapers, and
magazinesmagazines
Read print andRead print and
online trade journals,online trade journals,
newspapers, andnewspapers, and
magazinesmagazines
Talk with otherTalk with other
systems analystssystems analysts
Talk with otherTalk with other
systems analystssystems analysts

What are three basic documents used to summarize
technical specifications?
Less formal method
that uses standard
form to request
information about
product or service
Vendor quotes
price(s) for
listed
product(s)
Vendor selects
product(s) that
meet(s) your
requirements and
then quotes price(s)
Identifies
product(s)
you want
Request for information (RFI)Request for information (RFI)
Request for proposal (RFP)Request for proposal (RFP)
Request for quotation (RFQ)Request for quotation (RFQ)

How do systems analysts test software products?
 References from vendor
 Talk to current users of product
 Product demonstrations
 Trial version of software
 Benchmark test measures performance

What is a detailed design?
Includes several activities
Database
design
Database
design
Input and
output design
Input and
output design
Program
design
Program
design
Detailed design specifications for components in proposed solution

What is a mockup?
 Sample of input or output that contains actual data

What is a prototype?
Working model of
proposed system
Working model of
proposed system
Beginning a prototype
too early may lead to
problems
Beginning a prototype
too early may lead to
problems

What is computer-aided software engineering (CASE)?
 Software tools designed to support activities of system
development cycle

Convert to new systemConvert to new system
What is the implementation phase?
 Purpose is to construct, or build, new or modified
system and then deliver it to users
Train usersTrain users
Install and test new systemInstall and test new system
Develop programsDevelop programs

What are the three types of tests performed by system
developers?
Verifies application
works with other
applications
Systems test
Integration Test
Unit Test
Verifies each
individual program
works by itself
Verifies all programs
in application work
together

What is training?
 Showing users exactly
how they will use new
hardware and software
in system

What is the support phase?
Conduct post-implementation system review—meeting to find out if
information system is performing according to expectations
Identify errors
Identify enhancements
Monitor system performance
 Provides ongoing assistance after system is implemented

Advantages
1. Formal review is created at the end of each stage
allowing maximum management control.
2. This approach creates considerable system
documentation.
3. This documentation ensures that system
requirements can be traced back to stated business
requirements.
4. It produces many intermediate products that can be
reviewed to see whether they meet the user’s needs
and conform to standards. These can be further
worked on if they require tweaks to be made,
ensuring that the business gets exactly what it
needs.

Disadvantages
1. What may be seen as a major problem for some, end-user
does not see the solution until the system is almost
complete.
2. Users get a system that meets the need as understood by the
developers; this may not be what was really needed for
them. There may be a loss in translation.
3. Documentation is expensive and time-consuming to create.
It is also difficult to keep current. What may be current
this month may not be the same this time next year!
4. Users cannot easily review intermediate products and
evaluate whether a particular product (e.g., data flow
diagram) meets their business requirements.

system development life cycle SDLC

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