SDLC

Software Development Life Cycle Models and Methodologies

Introduction

Software development life cycle (SDLC) is a series of phases that provide a common understanding of the software building process. How the software will be realized and developed from the business understanding and requirements elicitation phase to convert these business ideas and requirements into functions and features until its usage and operation to achieve the business needs. A good software engineer should have enough knowledge on how to choose the SDLC model based on the project context and the business requirements.

Therefore, it may be required to choose the right SDLC model according to the specific concerns and requirements of the project to ensure its success. I wrote another article on how to choose the right SDLC, you can follow this link for more information. Moreover, to learn more about Software Testing life cycles and SDLC phases you follow the links highlighted here.

In this article, we will explore the different types of SDLC models and the advantages and disadvantages of each one, and when to use them.

You can think of SDLC models as tools that you can use to better deliver your software project. Therefore, knowing and understanding each model and when to use it, the advantages and disadvantages of each one are important to know which one is suitable for the project context.

tools
Tools

Types of Software developing life cycles (SDLC)

Waterfall Model

Description

The Waterfall Model is a linear sequential flow. In which progress is seen as flowing steadily downwards (like a waterfall) through the phases of software implementation. This means that any phase in the development process begins only if the previous phase is complete. The waterfall approach does not define the process to go back to the previous phase to handle changes in requirement. The waterfall approach is the earliest approach and most widely known that was used for software development.

Waterfall Model
Waterfall Model

The usage

For projects which not focus on changing the requirements, for example, projects initiated from a request for proposals (RFPs), the customer has very clear documented requirements

Advantages and Disadvantages

AdvantagesDisadvantages
  • Easy to explain to the users.
  • Structures approach.
  • Stages and activities are well defined.
  • Helps to plan and schedule the project.
  • Verification at each stage ensures early detection of errors/misunderstandings.
  • Each phase has specific deliverables.
  • Assumes that the requirements of a system can be frozen.
  • Very difficult to go back to any stage after it is finished.

  • A little flexibility and adjusting the scope are difficult and expensive.
  • Costly and required more time, in addition to the detailed plan.
Advantages/Disadvantages table

V-Shaped Model

Description

It is an extension of the waterfall model, Instead of moving down in a linear way, the process steps are bent upwards after the implementation and coding phase, to form the typical V shape. The major difference between the V-shaped model and the waterfall model is the early test planning in the V-shaped model.

V-Shaped
V-Shaped Model

The usage

  • Software requirements clearly defined and known
  • Software development technologies and tools are well-known

Advantages and Disadvantages

AdvantagesDisadvantages
  • Simple and easy to use
  • Each phase has specific deliverables.
  • Higher chance of success over the waterfall model due to the development of test plans early on during the life cycle.
  • Works well for where requirements are easily understood.
  • Verification and validation of the product in the early stages of product development.
  • Very inflexible, like the waterfall model.
  • Adjusting the scope is difficult and expensive. The software is developed during the implementation phase, so no early prototypes of the software are produced. The model doesn’t provide a clear path for problems found during the testing phases.
  • Costly and required more time, in addition to a detailed plan
Advantages/Disadvantages table

Prototyping Model

Description

It refers to the activity of creating prototypes of software applications, for example, incomplete versions of the software program being developed. It is an activity that can occur in software development and It used to visualize some components of the software to limit the gap of misunderstanding the customer requirements by the development team. This also will reduce the iterations that may occur in the waterfall approach and are hard to be implemented due to the inflexibility of the waterfall approach. So, when the final prototype is developed, the requirement is considered to be frozen.

It has some types, such as:

  • Throwaway prototyping: Prototypes that are eventually discarded rather than becoming a part of the finally delivered software
Throwaway prototyping
Throwaway prototyping
  • Evolutionary prototyping: prototypes that evolve into the final system through an iterative incorporation of user feedback.
Evolutionary prototyping
Evolutionary prototyping
  • Incremental prototyping: The final product is built as separate prototypes. In the end, the separate prototypes are merged in an overall design.
Incremental Model
Incremental prototyping
  • Extreme prototyping: used in web applications mainly. Basically, it breaks down web development into three phases, each one based on the preceding one. The first phase is a static prototype that consists mainly of HTML pages. In the second phase, the screens are programmed and fully functional using a simulated services layer. In the third phase, the services are implemented

The usage

  • This process can be used with any software developing life cycle model. While this shall be chosen when you are developing a system has user interactions. So, if the system does not have user interactions, such as a system does some calculations shall not have prototypes.

Advantages and Disadvantages

AdvantagesDisadvantages
  • Reduced time and costs, but this can be a disadvantage if the developer loses time in developing the prototypes.
  • Improved and increased user involvement.
  • Insufficient analysis. User confusion of prototype and finished system.
  • Developer misunderstanding of user objectives.
  • Excessive development time of the prototype.
  • It is costly to implement the prototypes
Advantages/Disadvantages table

Spiral Model (SDM)

Description

It is combining elements of both design and prototyping-in-stages, in an effort to combine advantages of top-down and bottom-up concepts. This model of development combines the features of the prototyping model and the waterfall model. The spiral model is favored for large, expensive, and complicated projects. This model uses many of the same phases as the waterfall model, in essentially the same order, separated by planning, risk assessment, and the building of prototypes and simulations.

spiral model
Spiral Model

The usage

It is used in large applications and systems which built-in small phases or segments.

Advantages and Disadvantages

AdvantagesDisadvantages
  • Estimates (i.e. budget, schedule, etc.) become more realistic as work progressed because important issues are discovered earlier.
  • Early involvement of developers.
  • Manages risks and develops the system into phases.
  • High cost and time to reach the final product.
  • Needs special skills to evaluate the risks and assumptions.
  • Highly customized limiting re-usability
Advantages/Disadvantages table

Iterative and Incremental Model

Description

It is developed to overcome the weaknesses of the waterfall model. It starts with initial planning and ends with deployment with the cyclic interactions in between. The basic idea behind this method is to develop a system through repeated cycles (iterative) and in smaller portions at a time (incremental), allowing software developers to take advantage of what was learned during the development of earlier parts or versions of the system. It can consist of mini waterfalls or mini V-Shaped models.

incremental-sdlc

The usage

It is used in shrink-wrap applications and large systems which built-in small phases or segments. Also, can be used in a system that has separated components, for example, an ERP system. Which we can start with the budget module as a first iteration and then we can start with the inventory module and so forth.

Mini V-Model
Iterative and Incremental Model

Advantages and Disadvantages

AdvantagesDisadvantages
  • Produces business value early in the development lifecycle.
  • Better use of scarce resources through proper increment definition.
  • Can accommodate some change requests between increments.
  • More focused on customer value than the linear approaches.
  • We can detect project issues and changes earlier.
  • Requires heavy documentation.
  • Follows a defined set of processes.
  • Defines increments based on function and feature dependencies.
  • Requires more customer involvement than the linear approaches.
  • Partitioning the functions and features might be problematic.
  • Integration between the iterations can be an issue if it is not considered during the development and project planning.
Advantages/Disadvantages table

Agile Model

Description

It is based on iterative and incremental development, where requirements and solutions evolve through collaboration between cross-functional teams.

agile-SDLC
Scrum Agile Model

The usage

It can be used with any type of project, but it needs more engagement from the customer and to be interactive. Also, we can use it when the customer needs to have some functional requirements ready in less than three weeks and the requirements are not clear enough. This will enable more valuable and workable pieces for software early which also increases customer satisfaction.

Advantages and Disadvantages

AdvantagesDisadvantages
  • Decrease the time required to avail some system features.
  • Face-to-face communication and continuous inputs from customer representatives leave no space for guesswork. The end result is high-quality software in the least possible time duration and satisfied customers
  • Scalability.
  • The ability and collaboration of the customer to express user needs.
  • Documentation is done at later stages.
  • Reduce the usability of components.
  • Needs special skills for the team.
Advantages/Disadvantages table

Here is a consolidated presentation to illustrate most of the popular software development models.

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Summary
Software Development Life Cycle Models and Methodologies
Article Name
Software Development Life Cycle Models and Methodologies
Description
Software development life cycle (SDLC) is a series of phases that provide a common understanding of the software building process.
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395 responses to “Software Development Life Cycle Models and Methodologies”

  1. Alvin Avatar
    Alvin

    Can you suggest a model for me? my project is about an Android application that measures foot of a person

    1. melsatar Avatar

      Is it connected with external device?

      1. Alvin Avatar
        Alvin

        nope it measures with the camera of the phone using the A4 sized paper as its reference.

        1. melsatar Avatar

          Good idea, I think in this kind of application, the requirements are more clear and also focus on one feature, so any methodology I think can fit. If you are planning to do other features you can use iteration model.

          1. Alvin Avatar
            Alvin

            Thank you this site helps me understand more about sdlc models. thanks also for your fast response

            1. melsatar Avatar

              You are welcome, anytime 🙂

    2. mohi Avatar
      mohi

      hey alvin!
      can you tell me about your project?
      i am elaborate it for me

  2. pocket Avatar
    pocket

    Hi, i want to develop vehicle reservation system for college. What type sdlc is suitable ? Can you suggest for me. Thank you.

    1. melsatar Avatar

      I think the iterative model will be very effective, while you have to focus which module is the best to start with, for example, student registration or Vehicle master records or another thing.

  3. vignesha patel Avatar
    vignesha patel

    I want to develop web application like video streaming for that which SDLC model suitable

    1. melsatar Avatar

      I think something like video streaming needs heavy testing, and also the requirement may be clear enough. So, I think the spiral model may be good for it or v-shaped model.

      What do you think?

  4. ahmad Avatar
    ahmad

    developing a cloud based application. What type of sdlc method should i use?

    1. melsatar Avatar

      This is an open question, while I will choose Agile

  5. Arjun Avatar
    Arjun

    For WebSite design which SDLC model should follow

    1. melsatar Avatar

      This depends on many things, while Agile or iterative model will be great

  6. Sheikh Avatar
    Sheikh

    Dear sir, your web site helps me a lot in my studies 🙂
    I have a question which i can find the convincing answer, If u can help and guide please.
    Q: Which IT development method in use today & which one is useful to select & why?

    1. sharmarobin619 Avatar

      I guess Agile development is the most widely used development method.

      1. melsatar Avatar

        Yes, I think it is mainly used in Startups

  7. niruba Avatar
    niruba

    i want a develop a software for a university? which SDLC Model will u suggest for me for a high quality output in short time?

    1. Umair Avatar
      Umair

      i am developing the loan management system socould you please prefer what type of model i use???
      And could you please explain how could we about choosing the right model for any project i em too confuse in it please help ASAP

      1. melsatar Avatar

        Hi Umair,

        Please follow this link, you will find a post regarding that

        https://melsatar.wordpress.com/2012/03/21/choosing-the-right-software-development-life-cycle-model/

  8. kaddupochchi Avatar

    useful thank u

    1. melsatar Avatar

      You are welcome 🙂

  9. Neelam Lakshmana Avatar
    Neelam Lakshmana

    Hello Sir, please help me explaining “Having the most suitable process model alone would not justify success “. do you agree ? justify your answer

    1. melsatar Avatar

      Yes, I agree. The process needs skills and tools to be executed. So, you need well-trained resources to be able to manage, implement, and govern the process.

      There are other factors as well, while this will be enough

    2. melsatar Avatar

      Sorry for late reply

  10. zaid Avatar
    zaid

    is it possible to combine/merge different models like waterfall+prototype ,prototype+iterative and spiral+ prototype and many more to develop different software and many software developers use blend of different models so plz give examples if you have info about blending of these models

    1. melsatar Avatar

      Yes, sure you can. These are practices and you can have you own by mixing and merging them or even you can invent new model and share it with us 🙂

    2. melsatar Avatar

      Yes, it is possible. Moreover, some models are the enhanced version of another, for example, iterative is a waterfall enhanced version, while you can combine the prototype with iteration and you can apply spiral practices in iterative approach.

  11. Faiz Avatar
    Faiz

    hello. can i get reference about Evolutionary prototyping model. i can’t get reference in pdf. hope you can share it to me…thank you.

  12. bhupendr jangir Avatar
    bhupendr jangir

    I want to design a software.

    1. melsatar Avatar

      So, go ahead:)

  13. Hooriia Avatar
    Hooriia

    which sdlc model used to devlop web application (B2B portal)

    1. melsatar Avatar

      I think agile will be good 🙂

  14. akatzues Avatar

    Hi, we are creating an personnel profiling system and it is needed immediately, what kind of SDLC model should we used on our documentation? Thanks.🙂

    1. melsatar Avatar

      Agile will be the best for immediately :), but your team should be familiar with agile methodology.

  15. Maira Malik Avatar
    Maira Malik

    please sir! which SDLC model is best for software of racing games??

    1. melsatar Avatar

      Sorry for late reply, if you know the requirements well, you can go with iterative model, but after that for rapid demands and changes you will need to have you will go with agile

  16. Okolo Daniel Avatar

    please sir, which of this models is best for the development of graphic user interface of a life cycle cost analysis software

    1. melsatar Avatar

      Hi, I think it will be good to make iteration with prototype design for the UI

  17. ho11yspirit Avatar
    ho11yspirit

    hi i m doing ranch management system which SDLC TO USE

    1. melsatar Avatar

      I do not know much about ranch systems, but they look complex and consist of many modules and features, so it can be spiral model or iterative model with prototyping

  18. Francis Gumogda Avatar

    Hello. I’m doing my thesis right now and I just want to ask, what is the best software model for Payroll system? Thanks.

    1. melsatar Avatar

      It depends on many things, like requirements understanding and it’s readiness and the duration, customer flexibility. Many things, could you provide more details

Let me know your thoughts

Mohamed Sami

About the author

Mohamed Sami is a Industry Advisor who has a solid engineering background, he has more than 18 years of professional experience and he was involved in more than 40 government national projects with holding different roles and responsibilities, from national projects execution and management to drafting of the conceptual architecture and solutions design. Furthermore, Mohamed contributed to various digital strategies in the government sector, which improved his business and technical skills over his career development.

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