A Review on Various Software Development Life Cycle (SDLC) Models

Abstract

To satisfy the need of automate the different activities and satisfy the need of some standard and structural procedure or methodology which to be introduced in the industry so that the transition from manual to automated system became easy. This leads to the concept of System Development Lifecycle (SDLC) Models came into existence that emphasized on the need to follow some structured approach towards building new or improved system. There are five development models namely Linear Sequential Model, Iterative Model, Prototype Model, Spiral Model, V-shaped Model. All these models have cons as well as prons. The main objective of this research is to represent the different models of software development and make a comparative study of them to show the features and defects of each model. Keywords: Software Development Model (SDLC), Linear Sequential Model, Incremental Model, Prototype Model, Spiral Model, V-Shape Model.

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International Journal of Research in Computer and
Communication Technology, Vol 3, Issue 7, July- 2014
ISSN (Online) 2278- 5841
ISSN (Print) 2320- 5156
www.ijrcct.org Page 776
776
A Review on Various Software Development Life Cycle
(SDLC) Models
Prof. Seema Suresh Kute, Prof. Surabhi Deependra Thorat
Assistant Professor
MCA Department, MIT(E)
Aurangabad(M.S), India
Seemak0518@yahoo.in, Thorat.surabhi@gmail.com
Abstract
To satisfy the need of automate the different
activities and satisfy the need of some standard and
structural procedure or methodology which to be
introduced in the industry so that the transition
from manual to automated system became easy.
This leads to the concept of System Development
Lifecycle (SDLC) Models came into existence that
emphasized on the need to follow some structured
approach towards building new or improved
system. There are five development models namely
Linear Sequential Model, Iterative Model,
Prototype Model, Spiral Model, V-shaped Model.
All these models have cons as well as prons. The
main objective of this research is to represent the
different models of software development and
make a comparative study of them to show the
features and defects of each model.
Keywords:
Software Development Model (SDLC), Linear
Sequential Model, Incremental Model, Prototype
Model, Spiral Model, V-Shape Model.
1. Introduction
Everybody knows how the computer is important in
our day to day life. Now, computer uses in every
field like in industry, hospital, medicine, education,
agriculture even though in military area. Computer
is used for developing the countries. The tasks
which are very difficult and time consuming for
human being that task can be done by the computer
within some microseconds. Many companies make
the software programs for the purpose of giving
facilities to the offices.
During early software development some problems
are occurred. So, for avoiding these problems or
obstacles follow some structured flow of the
software engineering and develop the software
programs. Software engineering is the application
of a systematic, disciplined, quantifiable approach
to the development, operation, and maintenance of
software [8].
2. System Development Life Cycle
(SDLC) [1]
The Systems Development Life Cycle (SDLC),
or Software Development Life Cycle in systems
engineering, information systems and software
engineering, is the process of creating or altering
systems, and the models and methodologies that
people use to develop these systems. The concept
generally refers to computer or information
systems. In software engineering the SDLC concept
underpins many kinds of software development
methodologies. These methodologies form the
framework for planning and controlling the
creation of an information system the software
development process.
Understand the Project.
Do the project planning.
Understand the requirement.
Do the designing according to that coding the
planned solution.
Test the actual program.
For large software systems, each activity can be
very complex and procedures are needed to
perform it efficiently and correctly. So, the
activities may be so large that it cannot be handled
in single step and must be broken into smaller
modules. For example, design of a large software
system is always broken into multiple, distinct
design phases, starting from a very high level
design specifying only the components in the
system to a detailed design where the logic of the
components is specified. The basic activities or
phases to be performed for developing software
system are;
Determination of System’s Requirements
Design of system
Development (coding) of software
System Testing

International Journal of Research in Computer and
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ISSN (Online) 2278- 5841
ISSN (Print) 2320- 5156
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2.1 Linear Sequential Model
The Linear Sequential Model is the classical model
of software engineering. This model is one of the
oldest models and is widely used in government
projects and in many major companies. As this
model emphasizes planning in early stages, it
ensures design flaws before they develop. In
addition, its intensive document and planning make
it work well for projects in which quality control is
a major concern.
Fig. 01 Linear Sequential Model [3]:
The pure linear sequential lifecycle consists of
several non-overlapping stages. The model begins
with establishing system requirements and software
requirements and continues with architectural
design, detailed design, coding, testing, and
maintenance. The waterfall model serves as a
baseline for many other lifecycle models.
The following list details the steps for using the
waterfall starting coding. There is no overlap
between stages. In real-world development,
however, one can discover issues during the design
or coding stages that point out errors or gaps in the
requirements.
The linear sequential method does not prohibit
returning to an earlier phase, for example, returning
from the design phase to the requirements phase.
However, this involves costly rework. Each
completed phase requires formal review and
extensive documentation development. Thus,
oversights made in the requirements phase are
expensive to correct later.
Because the actual development comes late in the
process, one does not see results for a long time.
This delay can be disconcerting to management and
customers. Many people also think that the amount
of documentation is excessive and inflexible.
Although the linear sequential model has its
weaknesses, it is instructive because it emphasizes
important stages of project development. Even if
one does not apply this model, he must consider
each of these stages and its relationship to his own
project [2].
2.1.1 Linear Sequential Model Major
Potential [3]
This model is strait forward and easily
understood for use.
This model is easily manageable.
One phase of a model is completed at one time.
By using this model small qualitative projects
are done.
2.1.2 Linear Sequential Model Problem
Area[3]
If the problem occurs in starting phase of a
model then it is very hard to do the changes in
that phase.
Deliverable product is not produced within short
time
High amounts of risk and uncertainty.
This model is not used for complicated and
object oriented projects.
This model is not suitable for big quality
projects.
Not suitable for the projects where requirements
are change frequently.
2.1.3 When to use the Linear
Sequential Model[3]
Requirements are very well known, clear and
fixed.
Product definition is stable.
Technology is understood.
There are no ambiguous requirements
Ample resources with required expertise are
available freely
The project is short.
2.1.4 Projects where Linear Sequential
Method is suitable for SDLC
In development of database-related software, e.g.
commercial projects.
In development of E-commerce website or
portal.
In Development of network protocol software.
2.2 Incremental Model
The incremental model combines elements of the
linear sequential model (applied repetitively) with
the iterative philosophy of prototyping. The
Incremental model applies linear sequences in a
staggered fashion as calendar time progresses. Each
linear sequence produces a deliverable “increment”
of the software. For example, word-processing
software developed using the incremental Paradigm
might deliver basic file management, editing, and

International Journal of Research in Computer and
Communication Technology, Vol 3, Issue 7, July- 2014
ISSN (Online) 2278- 5841
ISSN (Print) 2320- 5156
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document production functions in the first
increment; more sophisticated editing and
document production capabilities in the second
increment; spelling and grammar checking in the
third increment; and advanced page layout
capability in the fourth increment. It should be
noted that the process flow for any increment can
incorporate the prototyping paradigm. When an
incremental model is used, the first increment is
often a core product. That is, basic requirements
are addressed, but many supplementary features
(some known, others unknown) remain
undelivered. The core product is used by the
customer (or undergoes detailed review). As a
result of use and/or evaluation, a plan is developed
for the next increment. The plan addresses the
modification of the core product to better meet the
needs of the customer and the delivery of additional
features and functionality. This process is repeated
following the delivery of each increment, until the
complete product is produced.
The incremental process model, like prototyping
and other evolutionary approaches, is iterative in
nature. But unlike prototyping, the incremental
model focuses on the delivery of an operational
product with each increment. Early increments are
stripped down versions of the final product, but
they do provide capability that serves the user and
also provide a platform for evaluation by the user.
Incremental development is particularly useful
when staffing is unavailable for a complete
implementation by the business deadline that has
been established for the project. Early increments
can be implemented with fewer people. If the core
product is well received, then additional staff (if
required) can be added to implement the next
increment. In addition, increments can be planned
to manage technical risks. For example, a major
system might require the availability of new
hardware that is under development and whose
delivery date is uncertain. It might be possible to
plan early increments in a way that avoids the use
of this hardware, thereby enabling partial
functionality to be delivered to end-users without
inordinate delay [8].
Fig.02 Incremental Model [9]
2.2.1 Major Potential of Incremental
Model [7]
Develop active software product within early stages
of software life cycle.
This model is more adaptive –less costly to do
the changes in requirements.
It is easier to test and debug during a smaller
iteration.
In this model customer can reply to every built.
Delivery cost of the product is less.
Handling the risk is very easy because the risks
are handled during the iteration.
2.2.2 Problem Area of Incremental
Model [7]
High quality planning and design is needed.
Clear interpretation of the whole system is
necessary before it can be broken down and
develops incrementally.
Total cost is higher than linear sequential model.
2.2.3 When to use the Incremental
Model [7]
This model can be used when the requirements of
the complete system are clearly defined and
understood.
Major requirements must be defined; however,
some details can evolve with time.
There is a need to get a product to the market
early.
A new technology is being used.
Resources with needed skill set are not available.
There are some high risk features and goals.
2.3 Prototype Model [6]
Fig.03 Prototype Model
The basic idea here is that instead of freezing the
requirements before a design or coding can
proceed, a throwaway prototype is built to
understand the requirements. This prototype is
developed based on the currently known
requirements. By using this prototype, the client
can get an “actual feel” of the system, since the
interactions with prototype can enable the client to
better understand the requirements of the desired
system. Prototyping is an attractive idea for
complicated and large systems for which there is no

International Journal of Research in Computer and
Communication Technology, Vol 3, Issue 7, July- 2014
ISSN (Online) 2278- 5841
ISSN (Print) 2320- 5156
www.ijrcct.org Page 779
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manual process or existing system to help
determining the requirements. The prototype is
usually not complete systems and many of the
details are not built in the prototype. The goal is to
provide a system with overall functionality.
2.3.1 Major Potential of Prototype
Model
Energetic users are involved in the development.
In this model the working system is provided so
that the users get a clear idea better of the system
being developed.
Delusion can be perceived much earlier.
Rapid user feedback is available leading to better
solutions.
Problems related to functionality can be
identified easily.
2.3.2 Problem Area of Prototype Model
Forefront is implemented and then repairing way
of building systems.
Practically, when we use this model if the scope
of the system may increase beyond the
expectation then the complexity of the system is
also increases.
Incomplete application may cause application not
to be used as the full system was designed.
Incomplete or deficient problem analysis.
2.3.3 When to use Prototype Model
Prototype model should be used when the desired
system needs to have a lot of interaction with the
end users.
Typically, online systems, web interfaces have a
very high amount of interaction with end users,
are best suited for Prototype model. It might take
a while for a system to be built that allows ease
of use and needs minimal training for the end
user.
Prototyping ensures that the end users constantly
work with the system and provide a feedback which
is incorporated in the prototype to result in a
useable system. They are excellent for designing
good human computer interface systems.
2.4 Spiral Model [5]
The spiral model, originally proposed by Boehm, is
an evolutionary software process model that
couples the iterative nature of prototyping with the
controlled and systematic aspects of the linear
sequential model. It provides the potential for rapid
development of incremental versions of the
software. Using the spiral model, software is
developed in a series of incremental releases.
During early iterations, the incremental release
might be a paper model or prototype. During later
iterations, increasingly more complete versions of
the engineered system are produced.
A spiral model is divided into a number of
framework activities, also called task regions.
Typically, there are between three and six task
regions.
The spiral model that contains six task regions:
Customer communication—tasks required to
establish effective communication between
developer and customer.
Planning—tasks required to define resources,
timelines, and other project related information.
Risk analysis—tasks required to assess both
technical and management risks.
Engineering—tasks required to build one or
more representations of the application.
Construction and release—tasks required to
construct, test, install, and provide user support
(e.g. documentation and training) [8].
Fig.04 Spiral Model
2.4.1 Major Potential of Spiral model
Avoidance of risk is intensifying due to high
amount of risk analysis.
Good for large and mission-critical projects.
Strong approval and documentation control.
Software is produced early in the software
lifecycle.
Additional Functionality can be added at a later
date.
Software is produced early in the software
lifecycle.
2.4.2 Problem Area of Spiral Model
This model is costly to use.
For doing the Risk analysis requires highly
specific expertise.
Success of projects is highly dependent on the
risk analysis phase.
This model doesn’t work well for smaller
projects.
2.4.3 When to use Spiral Model
When costs and risk evaluation is important.
For medium to high-risk projects.
Long-term project commitment unwise because
of potential changes to economic priorities.
Users are unsure of their needs.

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ISSN (Online) 2278- 5841
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Requirements are complex.
New product line.
Significant changes are expected (research and
exploration).
2.5 V-Shape Model [4]
V-model means Verification and Validation model.
Just like the waterfall model, the V-Shaped life
cycle is a sequential path of execution of processes.
Each phase must be completed before the next
phase begins. Testing of the product is planned in
parallel with a corresponding phase of
development.
Fig.05 V-Shape Model
2.5.1 Major Potential of V-Shape
Model
This model is very simple and easy to use.
Testing activities like planning, test
designing happens well before coding. This saves
a lot of time. Hence higher chance of success
over the waterfall model.
Defects that are found at early stage that can be
track easily and solve.
This model is keep away from the downward
flow of the defects.
This model is used for small projects where
requirements are easily understood.
2.5.2 Problem Area of V-Shape Model
Very rigid and least flexible.
Software is developed during the implementation
phase, so no early prototypes of the software are
produced.
If any changes happen in midway, then the test
documents along with requirement documents
has to be updated.
The V-shaped model should be used for small to
medium sized projects where requirements are
clearly defined and fixed.
The V-Shaped model should be chosen when
ample technical resources are available with
needed technical expertise.
High confidence of customer is required for
choosing the V-Shaped model approach. Since, no
prototypes are produced, there is a very high risk
involved in meeting customer expectation.
3. Conclusion
After studying of all models through the various
factors, it has been found that the linear sequential
model is used in database related projects in which
all the requirements are known to the project team
members before the project starts. Incremental
model is used for new technology and where
needed resources are not available. Prototype
model used to develop online systems for
transaction processing, web interfaces i.e. where
very high amount of interaction with end users.
Since significantly lead to the creation of working
model in lower capital cost. Spiral model is used
for high-risk projects, Long-term projects and
where significant changes are expected at lowest
cost. The V-shaped model is used for small size
projects where requirements are clearly defined and
fixed and when all type of technical resources are
available. One model overcomes the disadvantages
of other model. 4. References:
[1] Ian Sommerville, "Software Engineering",
Addison Wesley, 7th edition, 2004.
[2] Nabil Mohammed Ali Munassar1and A.
Govardhan2 “A Comparison between Five Models
of Software Engineering” IJCSI International
Journal of Computer Science Issues, Vol. 7, Issue
5, September 2010 ISSN (Online): 1694-0814.
[3] “istqbexamcertification.com/what-is-waterfall-
model-advantages-disadvantage”, by S Kumar - Jan
11, 2012.
[4] “istqbexamcertification.com/what-is-v-model-
advantages-disadvantages “, by S Kumar - Jan 13,
2012.
[5]”istqbexamcertification.com/what-is-spiral-
model-advantages-disadvantag”, by S Kumar - Jan
13, 2012
[6] “istqbexamcertification.com/what-is-prototype-
model-advantages-disadvantages”, by S Kumar -
Jan 12, 2012.
[7]”istqbexamcertification.com/what-is-Icremental-
model-advantages-disadvantages”, by S Kumar
Jan 13 2012.
[8] “Software Engineering A Practitioner’s
Approach”, Roger S. Pressman, McGraw-Hill
International Edition, 5th edition.

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Communication Technology, Vol 3, Issue 7, July- 2014
ISSN (Online) 2278- 5841
ISSN (Print) 2320- 5156
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[9] Sanjana Taya, Shaveta Gupta, “Comparative
Analysis of Software Development Life Cycle
Models ”, ijcst, Volume 2, Issue 4, Oct.-Dec. 2012
ISSN : 0976-8491(Online).
[10] Apoorva Mishra, Deepty Dubey, ”A
omparative Study of Different Software “.
Table1. Comparative Chart for Various SDLC Models
Features
Linear
Sequential
Model
Incremental
Model
Prototyping
Model
Spiral
Model
V-Shape
Model
Requirement
Specification
Beginning
Beginning
Frequently
Changed
Beginning
Beginning
Understanding
Requirements
Well Understood
Not Well
Understood
Not Well
Understood
Well
Understood
Well
Understood
Cost
Low
Low
High
Expensive
Expensive
Availability Of Reusable
Component
No
Yes
Yes
Yes
Yes
Complexity Of System
Simple
Simple
Complex
Complex
Complex
Risk Analysis
At Beginning
No Risk
Analysis
No Risk
Analysis
Yes
High Risk
User Involvement In All
Phases Of SDLC
Only At
Beginning
Intermediate
High
High
Only At
Beginning
Guarantee Of Success
Less
High
Good
High
High
Overlapping Phases
No Overlapping
No
Overlapping
Yes
Yes
No
Overlapping
Implementation Time
Long
Less
Less
Depends On
Project
Long
Flexibility
Rigid
Less
Flexible
Highly
Flexible
Flexible
Rigid
Changes Incorporated
Difficult
Easy
Easy
Easy
Easy
Expertise Required
High
High
Medium
High
High
Cost Control
Yes
No
No
Yes
Yes
Resource Control
Yes
Yes
No
Yes
Yes