Software Development Life Cycle: Explained

0:00 how do you decide what your next step on a project is let's hope you're not relying on a role of the dice especially when the decision concerns something as costly as software development in that case we suggest a tried and true method like the software development life cycle or sdlc it's a standardized process that describes different stages of building highquality software sdlc was conceived in the 1970s as a way of formulating the development of large-scale Business

0:28 Systems but it prevails today as a reminder of What stages a product goes through on the way to eventual we hope success there are many methodologies addressing this sequence of stages that you might have heard of so today we will talk about the phases of sdlc and the methodologies applying them the father of the software development life cycle was a computer scientist and a director at Lockheed software Technology Center in Austin

0:59 when instant wroy in his influential article managing the development of large software systems he described implementation steps that are similar to what we use today there are generally six stages of software development covered in sdlc planning and Analysis it's sometimes also called requirement analysis or has analysis as a separate stage before or after planning all in all at this prolonged stage the product team collects business and use requirements about what the

1:31 final product must do and how it should work cost and time estimation scoping and other planning activities all go here this is such an extensive phase that we have several videos covering software planning so make sure to check them out after this one second is designing after the planning stage you prepare the product's architecture and design here a software architect analyzes the requirements and sets the highlevel structure of the future systems describing what components on go

2:00 where and how they interact with one another they will also select a technology for development user experience and visual design can also be drafted at this stage clearly without this stage the following one can't happen the next phase development is a stage where programmers use the architect's design to write code that will finally turn the vision into a real thing this is where some aspects of the final product will be first revealed to stakeholders then testing more quality

2:30 assurance takes place testers and QA professionals review the products code and useability for bugs and errors so they can be fixed before the next stage deployment is when the product is released to the users sometimes this stage is combined with the following one maintenance where feedback is constantly gathered and the product receives continuous updates and support this includes both fixes and new features sometimes there's a prototyping stage between planning and designing a prototype is a simplified version of the

3:02 product used to validate the idea before any major work begins it doesn't even have to be coded the design can be used to receive feedback from stakeholders and users a prototype is the best way to verify requirements with minimal effort and costs so the number of phases and their titles can differ depending on the specifics of the projects or a particular methodology but a common understanding Remains the Same you start with a plan then then you design and

3:30 develop after that you test and then release a product but by itself sdlc is just a concept and it's used as a base for several models you apply that will give your project Clarity and help deliver the best results so what are they waterfall was the first software development approach described in Rey's article back in the 1970s and it adheres strictly to the sdlc stages the main idea is that each stage starts only

4:01 after the previous one is finished the timeline due dates and deliverables are clearly set the waterfall model was borrowed from the construction and Manufacturing Industries where it makes total sense you need to wait for the blueprints before laying any bricks this model is very straightforward and well defined and the team can focus on just one phase at each point in time so the project is easier to manage but today it's fallen out of favor in the

4:27 engineering World why the main reason is that it's the opposite of flexible whenever you need to make a change in requirements or design you need to roll back to stage one and do the whole cycle all over again what if at the Finish Line you've identified some unforeseen risks that should have been mitigated during planning when testing happens so late in the process and stages don't overlap it inevitably leads to blown deadlines and budgets so in modern software

4:56 development a different approach is used today agile philosophy is the king the agile Manifesto which was written by 17 software developers in 2001 was a direct response to the heavyweight waterfall methodology among its 12 principles there are calls to welcome change even in late development stages and to deliver software continuously and early agile solved the waterfall drawbacks in a few ways firstly the testing phase

5:27 isn't separate from the building phase but rather it's done at every iteration for example in scrum one of the Frameworks based on agile the development is broken down into smaller Cycles Sprints Sprints are considered to be part of the scrum development framework and they are short periods of time typically lasting from 1 to 4 weeks at each Sprint cycle the team Works through all stages at the end of the Sprint the finished piece of product is shown to

5:54 stakeholders the short feedback loop allows devs to adapt quickly and find new approaches faster without compromising the delivery date another key change that agile brought to the development life cycle is the approach to planning or more specifically to documentation one of the main values listed in the agile Manifesto says working software over comprehensive documentation but the assumption that agile teams use little to no docs is wrong in waterfall the idea was to create detailed documentation covering

6:25 project goals and the working process as well as precise budget and time estimates for agile where change is welcome this would be just a waste of time so the idea is to produce only essential docks that is just barely good enough yes this is a real term in agile plus it must be a collaborative effort where a tech writer asks the team for feedback and encourages others to share their ideas if you want to learn more

6:52 about documentation types and how they're created we have a few videos you'll find useful while originally agile was more of a philosophy today it has loads of specific tools and techniques such Frameworks as scrum lean extreme programming or conon are also classified as agile approaches even though they existed before the agile Manifesto was formulated they now fall under the agile umbrella each framework has its best applications and specific tool set apart from the aforementioned

7:24 scrum there's a lean methodology that focuses on eliminating waste and at its core is a feedback loop for testing your assumptions it consists of three recurrent steps build which basically means drafting some version of the product such as an MVP measure meaning collecting feedback and evaluating if this version of the product succeeds and learn drawing conclusions and deciding how you refine your product for the next Loop another framework called Extreme programming or XP uses the usual life cycle but

7:56 emphasizes the technical aspect of development it uses such practices as test driven development code refactoring pair programming and more also kbon is more of a management method than a framework since it uses so-called conon boards to visualize work for efficiency there are many more Frameworks in the Agile development process that can be used depending on what the team wants or the project requires around 2008 A New Concept emerged from agile that drastically changed how software is built and

8:27 released today devops is one of the most discussed development approaches employed by such Giants as Amazon Netflix Google and Facebook it stands for development and operations devops introduces a cultural shift where different teams work together developers qas and operations are no longer writing the code testing it and deploying and supporting the code apart from one another now they merge

8:58 into a single team often having multi-disciplinary skills devops life cycle is typically visualized as an infinity loop representing the development processes on the left side and operations on the right side a team collaborates and communicates throughout each phase we have a whole separate video covering devops and a video series about all devops aspects you need to know so check it out after this one what's important is that devops uses typical agile planning the product

9:28 development has rough objectives outlined and only the few future Sprints are detailed so while agile is focused on identifying features that users will like devops make sure that existing processes are optimized and streamlined to do that devops uses CI CD continuous integration and continuous delivery or cicd is a set of principles that allow developers to deliver frequent code changes it means that teams integrate code on a daily or even

9:59 an hourly basis by merging code changes in a central repository and preparing for deployment at any moment basically all changes new features and Bug fixes are always ready to be deployed and the product can be updated multiple times per day continuously delivering value to users HubSpot shared that they add 200 to 300 deployments a day using cicd Netflix orchestrates over 20,000 deployments daily in 2022 11% of organiz Iz ation were considered high devops

10:31 performers and deployed 417 more times than low performers this is of course achieved by high levels of Automation and the infrastructure that connects all aspects of product delivery and a unified ecosystem although cicd facilitates agile practices such as getting feedback quickly and detecting errors in the early stages it doesn't require short iterations and introduces automation to the development life cycle even in agile introducing product changes can be a

11:01 long process especially today when technological innovations happen so fast and consumer needs change easily so cicd solves this problem by adapting in a short amount of time without disrupting the whole development flow and consumers get to see the new features added in real time and provide their feedback instantly for 60 years the phases of the software development life cycle remained relatively unchanged regardless of whether you're building a house a rocket ship or an app you will need to plan

11:33 design build test deploy and maintain the product what matters is the relations between these phases now when testers and devs collaborate or are even capable of doing the same job you don't need to separate those tasks much automation tools made it possible to do many things at the same time and shrink the cycle to days and hours agile and many models and approaches that spurted from it have remained relevant for decades perhaps they will last another

12:01 decade or maybe a new hip technology will show us a more efficient way to follow the product development path regardless we will keep you updated let us know if you enjoyed the video like And subscribe if you want more videos like this we'll see you soon in the next video yeah