SIA-101-Final-_SDLC.pdf

SDLC
SOFTWARE DEVELOPMENT LIFE CYCLE
B y : E n g r . R o l a n B . A n d a l , C C N A , M S I T
I T P r o f e s s o r : A I T E C o l l e g e D e p t .
E m a i l : a n d a l r o l a n b @ g m a i l . c o m

Agenda
Topic one – What is a SDLC
Topic two – SDLC Phases
Topic three – SDLC Models

Introduction
SDLC - Overview
Software Development Life Cycle (SDLC)
 is a process used by the software industry to design, develop and
test high quality software.
 aims to produce a high-quality software that meets or exceeds
customer expectations, reaches completion within times and cost
estimates.
 acronym of Software Development Life Cycle.
 It is also called as Software Development Process.
 is a framework defining tasks performed at each step in the
software development process.
Take Note:
ISO/IEC 12207 is an international standard for software life-cycle
processes. It aims to be the standard that defines all the tasks
required for developing and maintaining software.
Presentation Title

What is a SDLC?
Software Development life cycle

SDLC is a pro cess followed for a software project, within a s oftware organization . It c on sis ts o f a detailed plan
describin g how to develop, maintain, replace and alter or en hance s pecific s oftware. T he life c ycle defines a
metho dology fo r impro ving the quality of software an d the o verall development proc es s.
Figure Shows following figure is a graphical representation of the various stages of a typical SDLC.
Figure. 1
Figure. 2
Figure.3

However, the most common SDLC structures are variations on the following phases:
Figure 4. Shows most common SDLC structures are variations on the following phases.
Figure. 4
1.Planning and Analysis
2.Design
3.Development
4.Testing
5.Deployment
6.Maintenance

Why is the software development life cycle important?
7
Defining and following the phases of a software development life cycle results in improved quality of resulting
software product while simultaneously reducing the time needed to build and deploy it and reducing overall costs.
Following an SDLC achieves those gains for the software development process by:
•Providing management with a higher degree of oversight and control.
•Improving documentation.
•The goal the software being developed is designed to reach is clarified and agreed upon by all stakeholders
upfront and a clear roadmap to arriving at that goal is laid out.
•All stakeholders can provide their input at the most appropriate and effective phase of the software
development process.
•Developers have a clear understanding of what they should build and why.
•All stakeholders are aware of and buy into the allocation of the resources required to attain the software
development project’s goal.

Does a software development life cycle always follow the same phases in the same order?
8
Not every software development life cycle is the same. Different software development methodologies and
frameworks have their own variations on the SDLC phases..
•Some, for example Crystal, even leave flexibility for the team working on a software development project to
set their own SDLC phases as they decide is most appropriate to the piece of software being developed.
Crystal or also known as Crystal Methods are a family of
methodologies (the Crystal family) developed by Alistair
Cockburn from his study and interviews of teams in 1998.

Does a software development life cycle always follow the same phases in the same order?
9
Another example is the Agile framework Extreme Programming (XP)
follows a 5-stage software development life cycle:
Agile software development is an iterative
approach to creating software products based on
quickly releasing a minimum viable product (MVP)
and then adjusting it and adding features and
functionalities in stages based on user behaviour
and feedback. The methodology is designed to
address the fact it can be difficult to accurately
predict the most intuitive user journeys, features
and functionalities users need, prefer and desire
from software.
Agile is being characterized by the division of tasks into short phases of work and frequent reassessment and adaptation of
plans.
"agile methods replace high-level design with frequent redesign"

Common phases of the software development life cycle
Stage 1: Planning and Requirement Analysis
 Requirement analysis is the most important and fundamental stage in SDLC.
 It is performed by the senior members of the team with inputs from the customer, the sales
department, market surveys and domain experts in the industry. This information is then
used to plan the basic project approach and to conduct product feasibility study in the
economical, operational and technical areas.
 Planning for the quality assurance requirements and identification of the risks associated
with the project is also done in the planning stage.
 The outcome of the technical feasibility study is to define the various technical approaches
that can be followed to implement the project successfully with minimum risks.

•What problem will the software solve? What is solving that problem potentially worth?
•How big a potential user base does the software have?
•Does other software exist that solves the same problem?
•How will this software improve on that?
•How much might it cost to develop software to effectively solve the problem?
•Is solving the problem valuable enough to offer an acceptable return on investment on that cost?
•Do we have the resources to support that cost?
Planning and analysis processes are often conflated into a single software development life cycle phase.
But they are just as often split out into two separate phases.
During this first phase, the business case for developing a piece of software is analysed. Among the questions that
would typically be asked at this stage are:

The project’s scope, or initial estimate of scope in an Agile approach, would be discussed here based on initial
feature requirements or assumptions. As would planning of the resources needed to realise the project and
then putting them in place, including the software development team
Phase 2.: Presumptions contained in the answers to these questions should be verified, preferably through
methods like user focus groups, other market research tools including things like SMS marketing, online surveys,
developing a technical prototype etc.
Goals and limitations are set.
The software development team roles most typically involved in the planning and analysis phase of the software
development life cycle (this varies from team to team and is influenced by the chosen methodology/framework)
are:
•Product owner
•Project manager
•CTO (Chief Technology Officer)
•Business analyst
A chief technology officer (CTO) (also known as a chief technical
officer or chief technologist) is an officer tasked with managing technical
operations of an organization. They oversee and supervise research and
development and serve as a technical advisor to a higher executive such as
a chief executive officer

Stage 2: Design
 Decisions will also be made on infrastructure, like if the software will be cloud-hosted and if that will involve
a public cloud, private cloud or hybrid approach and providers. Security requirements are an important part
of the design phase and will inform many of the decisions taken.
Once the need for the software has been verified and its initial scope and requirements and resources
expected to be needed are established during the analysis and planning phase, the design phase kicks in.
 This is where software architects and developers make decisions on the high-level design of the software
system. A tech stack will be chosen, like what languages, frameworks and libraries will be used on the front
end and back end and other details like the choice of database technology and other third party services.
 Throughout the design phase, stakeholders should be consulted on tech stack choices, risks, resources
required in the context of design decisions taken, time, budget, regulatory and other project constraints.
 The scope and features is to be released first should also be decided upon here as it will inform the
next phase – development.
Team roles central to the design phase of the SDLC include:
•Software architect
•UI/UX designers

Stage3:
Development
The development phase of the software development life cycle is where the product is coded
and put together by developers. In an Agile approach, which most significant software
development projects take, the first development phase of an iterative SDLC
In a Waterfall( Model) approach, what is seen as the finished product is documented in
technical detail from beginning to end during the design phase and then build from beginning
to end during the development phase.
The team roles most involved in the development phase are:
 Front-end developers
 Back-end developers
 UI/UX designers
What is the meaning of UI UX?
UX (user experience) and UI (user interface) are two interdependent terms.
While UI generally deals with the interaction between users and computer
systems, software and applications, UX deals more generally with a user's
overall experience with a brand, product or service.

Stage4:
Testing
During the testing phase, the software developed in the previous phase is tested against requirements defined in the planning and
analysis phase as well as for performance and bugs. The goal of the phase is to ensure the software product has been developed as
intended, both in terms of user experience and the resources needed for it to run smoothly and meet availability and security
requirements.
Software testing usually involves both manual testing of user journeys and experience as well as automated
testing based on tools and scripts. If bugs or other defects are found, testers must document the issue and
inform the development team who will create a new version of the software in which the issues have been
resolved. That version of the software will then be tested again in case updates have had unintended
consequences and created new bugs or defects.
In a DevOps approach to the software development life
cycle, the development and testing phases are tightly
integrated with testing a continuous process during
development and could even be described as a single,
unified phase.
The team roles most involved in the testing phase are:
•Solutions architect
•QA engineer
•Tester
•DevOps engineer

Stage4:
Deployment
The deployment phase sees a software application moved from its development and testing environments into a live environment where it
is available to users. Deployment can be a relatively simple process or an extremely complex one, depending on the nature of the
software. For example, if a new software product involves a database other systems will use, integrating them all could represent a
significant undertaking.
A crucial step in the deployment phase is also making sure, which means testing, that the software works exactly the same way in the live
environment as it does in the development and testing environments. In a DevOps CI/CD software development pipeline pre-deployment
and live environments should be identical, minimizing the risk of discrepancies between how the software runs. DevOps tightly integrates
the development and deployment phases.
The most prominent team roles in the deployment phase of the SDLC are:
•DevOps engineer
•Database administrator

Stage4:
Maintenance
The maintenance phase involves making sure the software application continues to run as it is
intended to in terms of functionalities, performance and availability. Users and ongoing testing may
uncover bugs and other defects, or security issues, not found during the testing phase, which
should be fixed. These may be minor or necessitate the launch of a new development phase.
The main roles in the maintenance phase are most after:
•Users
•Testers
•Support managers

Software development life cycle? and System development life cycle?
Software development life cycle is about building a software (“only”) in a phased approach systematically.
System development life cycle is about implementing hardware and software in a phased manner
systematically. Here both the hardware and the software is considered as a system.
SDLC can also stand for ‘system development life cycle’ when used more holistically to ensure security
controls and requirements are designed rather than retrofitted into the software development process.
When the ‘S’ of SDLC stands for ‘system’, it covers people, processes, software components,
infrastructure, and change management.
It’s the more ‘general’ project management term while ‘software development life cycle’ has a targeted
focus on just the software components.
Take note:

In conclusion for SDLC 6 Phases
The software development life cycle can and is adapted by
software development teams based on the philosophy,
methodology and framework they adopt when building a
given software product, or between organizations.
Little, if anything, is written in stone, nor should it be.
The SDLC is a tool in the project management box and
should fit the needs of a particular project, the team
working on it and other key stakeholders involved in the
process. Phase names, their order, or if they are distinct
or conflated into each other change.
But every software development project has a life cycle,
and you should now have a good understanding of its role
in project management and as a tool used to improve
outcomes.
( A n d w h e n d o e s n ’ t i t ? )
F i n d o u t h e r e !
Presentation Title

SDLC Models
Presentation Title

SDLC Models
 Software Development life cycle (SDLC) is a spiritual model used in project management that defines the
stages include in an information system development project, from an initial feasibility study to the
maintenance of the completed application.
 There are different software development life cycle models specify and design, which are followed
during the software development phase.
These models are also called "Software
Development Process Models." Each process
model follows a series of phase unique to its type
to ensure success in the step of software
development.

SDLC Models – Waterfall Model
 Here, are some important phases of SDLC life cycle:
Waterfall Model
The waterfall is a universally accepted SDLC
model. In this method, the whole process of
software development is divided into various
phases.
The waterfall model is a continuous software
development model in which development is
seen as flowing steadily downwards (like a
waterfall) through the steps of requirements
analysis, design, implementation, testing
(validation), integration, and maintenance.

Waterfall model
 Winston Royce introduced the Waterfall Model in 1970.
 The steps always follow in this order and do not overlap.
 The developer must complete every phase before the next phase begins.
 This model is named "Waterfall Model", because its diagrammatic representation
resembles a cascade of waterfalls.

Waterfall model Stages
Requirements analysis
Design
Implementation/Coding
Testing
Deployment
Maintenance

Waterfall model
Advantages of Waterfall model
 This model is simple to implement also the number of resources that are required for it is minimal.
 The requirements are simple and explicitly declared; they remain unchanged during the entire
project development.
 The start and end points for each phase is fixed, which makes it easy to cover progress.
 The release date for the complete product, as well as its final cost, can be determined before
development.
 It gives easy to control and clarity for the customer due to a strict reporting system.
Disadvantages of Waterfall model
 In this model, the risk factor is higher, so this model is not suitable for more significant and complex
projects.
 This model cannot accept the changes in requirements during development.
 It becomes tough to go back to the phase. For example, if the application has now shifted to the
coding phase, and there is a change in requirement, It becomes tough to go back and change it.
 Since the testing done at a later stage, it does not allow identifying the challenges and risks in the
earlier phase, so the risk reduction strategy is difficult to prepare.

Iterative Waterfall Model
What is the Waterfall software development methodology
and is it still relevant?
In 2021 the Waterfall methodology is broadly considered an outdated
approach to software development but are there circumstances under which
it might still be relevant?
In a practical software development project, the classical waterfall model is hard to
use. So, the Iterative waterfall model can be thought of as incorporating the necessary
changes to the classical waterfall model to make it usable in practical software
development projects. It is almost the same as the classical waterfall model except some
changes are made to increase the efficiency of the software development.
The iterative waterfall model provides feedback paths from every phase to its preceding
phases, which is the main difference from the classical waterfall model.

RAD Model
Rapid Application development

SDLC Models – RAD - Rapid Application Development
Rapid Application development
RAD or Rapid Application Development process is an adoption of the waterfall model; it targets
developing software in a short period. The RAD model is based on the concept that a better
system can be developed in lesser time by using focus groups to gather system requirements.
Traditional development methodologies, like the waterfall
approach, don’t cut it any longer. But the RAD model does.
The idea is to adapt quickly to problems, opportunities, and updates, while being
able to make data-driven decisions and base the design and development of the
solution on both requirements and knowledge gained from previous or on-going
processes.
Rapid Application Development Phases
The winning formula mentioned above consists of 4 rapid
application development stages:
1.Plan Requirements
2.User Design and Input
3.Rapid Construction
4.Finalization

Stage 1: Outlining the product’s “gist (the substance or essence)” is the first step in the RAD
process. This is when programmers, product owners, managers, users, and designers gather to
summarize the scope, needs, purpose, potential obstacles, and other project’s specificalities.
But they keep the requirements flexible enough so they can more easily undergo any updates if
necessary.
Stage 2: This is a continuous RAD phase that lasts from start to finish and is usually associated
with prototyping and testing. Users work alongside the technical team to give feedback on the
ways the system has been working so far, address shortcomings, clarify features, functionalities,
and user flows that need to be changed/kept, define how intuitive and user-friendly the
software is turning out, and so forth.
Stage 3: Here’s when features and functionalities are finalized, and developers start working
on the product construction based on the feedback collected from the previous phase. One of
the major differences between RAD and other models gets most noticeable in the rapid
construction phase precisely, because it presents programmers with the modules that have
already been discussed, built and tested in the prototypes. So, it is a huge time-saver.
Stage 4: After final testing, user training, interface fine-tunes, quality and stability
assessments, the product moves from approval to live environment.
Rapid Application Development Phases

RAD Model Advantages - Or the Aspects That Will Make You Go from Waterfall to Agile.
•Reduces risk from infeasible designs that turn out to be far too complex to execute.
•Weeds out problems and bugs earlier in the project life cycle rather than when the system is already implemented.
•Allows for quick reviews and lets users experience prototypes, provide constructive feedback and identify possible improvements more
effectively.
•Invites users throughout the entire process and not just at the beginning/end, which eliminates design and UX discrepancies more easily.
•The system can be built in modules and functionality-by-functionality, allowing for more detailed testing and insight into the aimed business
aspect of it.
•Delivering better quality and more usable software through well-tested prototypes and RAD projects take typically less time to complete and
progress hand in hand with UX.
•Minimizes the planning phase and nourishes fast-paced prototype iterations.
•PMs and stakeholders can better monitor progress and results, because the project is usually broken down into chunks and more manageable
tasks.
•Eliminates error-prone hand coding and encourages code reuse with the easy integration of low-code/no-code tools and automation.
Rapid Application Development Advantages and Disadvantages

Disadvantages - Or the Things to Keep in Mind Before You Jump Straight to Agile
•May result in ignoring the system’s architecture and deemphasizing the non-functional requirements (NFRs).
•Not applicable to large scale teams and projects that require full control and better planning.
•It is more difficult and scattered to manage due to its flexibility and iterative nature.
•Works on 100% for modular systems only.
•May require too frequent meetings due to potentially recurrent cycles of prototypes.
•Some back-end processes and best practices are compromised due to the focus on the facade – the user-
facing front-end (this can be eliminated with the use of low-code development tools but more about this
follows below).
Rapid Application Development Disadvantages

SDLC Model: Spiral Model
The Spiral Model is one of the most
important Software Development Life Cycle models,
which provides support for Risk Handling.

What is the Spiral Model?
The Spiral Model is a Software Development Life Cycle
(SDLC) model that provides a systematic and iterative
approach to software development. In its diagrammatic
representation, looks like a spiral with many loops. The exact
number of loops of the spiral is unknown and can vary from
project to project. Each loop of the spiral is called a Phase of
the software development process.

1.The exact number of phases needed to develop the product can be varied by
the project manager depending upon the project risks.
2.As the project manager dynamically determines the number of phases, the
project manager has an important role in developing a product using the spiral
model.
3.It is based on the idea of a spiral, with each iteration of the spiral
representing a complete software development cycle, from requirements
gathering and analysis to design, implementation, testing, and maintenance.
.

1 . P l a n n i n g
T h e f i r s t p h a s e o f t h e S p i r a l M o d e l is t h e p l a n n i n g p h a s e , w h e r e t h e s c o p e o f t h e p r o j e c t is d e t e r m i n e d , a n d a
p l a n i s c r e a t e d f o r t h e n e x t i t e r a t i o n o f t h e s p i r a l .
. 2 . R i s k A n a l y s i s
I n t h e r i s k a n a l y s is p h a s e , t h e r i s k s a s s o c i a t e d w i t h t h e p r o j e c t a r e i d e n t i f i e d a n d e v a l u a t e d .
3 . E n g i n e e r i n g
I n t h e e n g i n e e r i n g p h a s e , t h e s o f t w a r e is d e v e l o p e d b a s e d o n t h e r e q u ir e m e n t s g a t h e r e d in t h e p r e v i o u s
i t e r a t i o n .
4 . E v a l u a t i o n
I n t h e e v a l u a t i o n p h a s e , t h e s o f t w a r e i s e v a l u a t e d t o d e t e r m i n e i f it m e e t s t h e c u s t o m e r ’ s r e q u ir e m e n t s a n d if it
i s o f h ig h q u a l i t y .
5 . P l a n n i n g
T h e n e x t i t e r a t i o n o f t h e s p i r a l b e g i n s w i t h a n e w p l a n n i n g p h a s e , b a s e d o n t h e r e s u l t s o f t h e e v a l u a t i o n .
What Are the Phases of Spiral Model?
The Spiral Model is a risk-driven model, meaning that the focus is on managing risk through
multiple iterations of the software development process. It consists of the following phases:

The Spiral Model is often used for complex and large software development projects, as it
allows for a more flexible and adaptable approach to software development. It is also well-
suited to projects with significant uncertainty or high levels of risk.
The Radius of the spiral at any point represents the expenses(cost) of the project so far, and
the angular dimension represents the progress made so far in the current phase.

Each phase of the Spiral Model is divided into four quadrants as shown in the above
figure. The functions of these four quadrants are discussed below:
1.Objectives determination and identify alternative solutions: Requirements are gathered from the customers and the
objectives are identified, elaborated, and analyzed at the start of every phase. Then alternative solutions possible for the
phase are proposed in this quadrant.
2.Identify and resolve Risks: During the second quadrant, all the possible solutions are evaluated to select the best
possible solution. Then the risks associated with that solution are identified and the risks are resolved using the best
possible strategy. At the end of this quadrant, the Prototype is built for the best possible solution.
3.Develop the next version of the Product: During the third quadrant, the identified features are developed and verified
through testing. At the end of the third quadrant, the next version of the software is available.
4.Review and plan for the next Phase: In the fourth quadrant, the Customers evaluate the so-far developed version of the
software. In the end, planning for the next phase is started.

Advantages of the Spiral Model
Below are some advantages of the Spiral Model.
1.Risk Handling: The projects with many unknown risks that occur as the development proceeds,
in that case, Spiral Model is the best development model to follow due to the risk analysis and risk
handling at every phase.
2.Good for large projects: It is recommended to use the Spiral Model in large and complex
projects.
3.Flexibility in Requirements: Change requests in the Requirements at a later phase can be
incorporated accurately by using this model.
4.Customer Satisfaction: Customers can see the development of the product at the early phase of
the software development and thus, they habituated with the system by using it before
completion of the total product.
5.Iterative and Incremental Approach: The Spiral Model provides an iterative and incremental
approach to software development, allowing for flexibility and adaptability in response to
changing requirements or unexpected events.
6.Emphasis on Risk Management: The Spiral Model places a strong emphasis on risk
management, which helps to minimize the impact of uncertainty and risk on the software
development process.
7.Improved Communication: The Spiral Model provides for regular evaluations and reviews,
which can improve communication between the customer and the development team.
8.Improved Quality: The Spiral Model allows for multiple iterations of the software development
process, which can result in improved software quality and reliability.

Disadvantages of the Spiral Model
Below are some main disadvantages of the spiral model.
1.Complex: The Spiral Model is much more complex than other SDLC models.
2.Expensive: Spiral Model is not suitable for small projects as it is expensive.
3.Too much dependability on Risk Analysis: The successful completion of the project is
very much dependent on Risk Analysis. Without very highly experienced experts, it is
going to be a failure to develop a project using this model.
4.Difficulty in time management: As the number of phases is unknown at the start of the
project, time estimation is very difficult.
5.Complexity: The Spiral Model can be complex, as it involves multiple iterations of the
software development process.
6.Time-Consuming: The Spiral Model can be time-consuming, as it requires multiple
evaluations and reviews.
7.Resource Intensive: The Spiral Model can be resource-intensive, as it requires a
significant investment in planning, risk analysis, and evaluations.

When To Use the Spiral Model?
1.When a project is vast in software engineering, a spiral model is utilized.
2.A spiral approach is utilized when frequent releases are necessary.
3.When it is appropriate to create a prototype
4.When evaluating risks and costs is crucial
5.The spiral approach is beneficial for projects with moderate to high risk.
6.The SDLC’s spiral model is helpful when requirements are complicated and ambiguous.
7.If modifications are possible at any moment
8.When committing to a long-term project is impractical owing to shifting economic
priorities.

SDLC Model: Prototype Model
 The prototype model requires that before carrying out the development of actual software, a
working prototype of the system should be built.
 A prototype is a toy implementation of the system.
 A prototype usually turns out to be a very crude version of the actual system, possible
exhibiting limited functional capabilities, low reliability, and inefficient performance as
compared to actual software.
 In many instances, the client only has a general view of what is expected from the software
product. In such a scenario where there is an absence of detailed information regarding the
input to the system, the processing needs, and the output requirement, the prototyping
model may be employed.

Steps of Prototype Model
1.Requirement Gathering and Analyst
2.Quick Decision
3.Build a Prototype
4.Assessment or User Evaluation
5.Prototype Refinement
6.Engineer Product

Advantage of Prototype Model
1.Reduce the risk of incorrect user requirement
2.Good where requirement are changing/uncommitted
3.Regular visible process aids management
4.Support early product marketing
5.Reduce Maintenance cost.
6.Errors can be detected much earlier as the system is made side by
side.
7.Prototyping tools are expensive.
8.Special tools & techniques are required to build a prototype.
9.It is a time-consuming process.

Disadvantage of Prototype Model
1.An unstable/badly implemented prototype often becomes
the final product.
2.Require extensive customer collaboration
1. Costs customer money
2. Needs committed customer
3. Difficult to finish if customer withdraw
4. May be too customer specific, no broad market
3.Difficult to know how long the project will last.
4.Easy to fall back into the code and fix without proper
requirement analysis, design, customer evaluation, and
feedback.

THANK YOU
P r e s e n t e d B y : E n g r . R o l a n B . A n d a l , C C N A , M S I T
I T P r o f e s s o r : A I T E C o l l e g e D e p a r t m e n t .
E m a i l : a n d a l r o l a n b @ g m a i l . c o m

SIA-101-Final-_SDLC.pdf

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