Waterfall Model

 In the last topic we learned about the Software Development Model. And In this topic we will study about Waterfall Model. What is this Waterfall Model? And in which project or product it is mostly used. Waterfall model is the oldest and most commonly used model. This is the 1^st SDLC model which is used for the development. Since 1950 waterfall model is used. Another name for waterfall model is Linear Sequential Model. Why have they kept this name Linear Sequential Model? You will even think that. The flow is from top to bottom, that is the reason why we will call this Linear Sequential Model. Let’s take a technical example to understand the waterfall model. If we want to make an address book. Right? Let’s say I want to make an address book of all my contacts. So, for that what would be the requirements? There should be one contact name, number, email ID, all those normal things should be there. After that what would be the functionality of the address book. Can the entire address book be mailed; can the entire address book be saved somewhere else? In this way the design of the requirements will be there, coding and then it will be implemented. Come, let’s see an example of Waterfall Model. Automobile Company that manufactures car and mobile. What will they do? They have a fixed requirements from the start. Like in the bike which model they require. Okay. What should be the features in the bike, should there be auto start or there should be kick in it. All these features would be decided from first. Similarly with the car. From inside the Auto Lock should be there or not. As soon as the requirement stage process gets complete, we will move to the next process. If there is any change in the requirement. So, I will have to again restart everything. Right? Because of it what will be the issue that we will have? We will have to start the entire system again. In it we will require more time and more money. This is a major disadvantage of the WaterFall Model. Now we will see the comparison of advantages and disadvantages of Waterfall Model. In this first is that this model is simple and easy to understand. It is simple as when one process ends the other process starts. So, it is simple for the understanding. But what is the disadvantage? Its disadvantage is that in the testing stage if there are any functionality issues that come. So, we will have to start the development from the start. Every model is independent from one other. Right? So, the management of each model is very easy. Like when the requirements come, we will review the requirements properly. Then the requirements will be delivered for designing. Similarly, we will properly review the design. After that we will go on to the implementation. It has an advantage but what is the disadvantage in front    of it. There is high amount of risk. Why there is a risk? If something changes somewhere, we will have to start from the start. In this any model process that is there, the stages that are there are not overlapped. The requirements are going on, so with it even the designing is also going on. And with the design implementation is also happening. This is not the case. Till the times the requirements are not over, till that time design will not happen. But what is the disadvantage of it? When there are big, heavy projects, at that time this process will be very poor. Where there are small projects, the waterfall model will work very well. But In the project where the requirements are changing continuously or which are not much fixed, there, if we don’t use the waterfall model that is better. Now, we will see in the next topic about Iterative Model.