Iterative Model

In the last topic we learned about the Waterfall Model. And In this topic we will learn Iterative Model. The Iterative Model does not start with full specifications of requirements. In this it is not that till the time all the requirements don’t come; the project will not start. We will start with whatever requirement is available. Development will implement a small part of the requirement. With this what will happen, whichever part is developed, we will review that and we will add the further requirements in it. On every cycle we will add a new model and we will develop this. Let’s understand it easily with the help of an example.. Like you can see the iPod of Apple. When Apple launched its 1^st iPod, which was called iPod Nano. You must have seen it; it was in square shape. Alright, it was in grey color. It was an MP3 Player. What was the main thing in it? To upgrade the series that was going on of the MP3 Players. So, in the 1^st iPod Nano which was launched, only the MP3 player was there and nothing else. Right? But when the iPod’s next version came, there were videos in it. In the next version there was a camera. In the latest version there is a health tracking app included. So, with this you can understand how in the Iterative Model the work happens in small phases and for every new requirement, a new product comes out with the existing requirement also. Now, this diagram is very easily understandable. Requirements, now we will again take an example of Apple iPods. We are talking about the iPod 1^st which was launched, the nano. For that what was the 1^st requirement, only MP3 Format songs should be played in it. So, what will be its design? How much should be its memory? What should be the shape of the MP3 player? square or circle. With that what we did? We implemented it. The size of the MP3 Player should be 1 GB. And the shape of it would be square. After that, we implemented it and tested it. Now, what we saw at the time of the review. That the product that is going to be launched outside, in which all functionality is there, which is working, like play, pause, next, fast/forward, stop. Right? Then the songs are playing one by one or not. Right? There are no double songs that are playing. There are a lot of things that we do in the review. And that type of complete product will be launched. Let’s understand the phases of the Iterative Model. What will happen in the requirement phase? All the requirements are gathered about the software, we will do an analysis of that. Design Phase, whatever requirement has come, we will make a design out of it. Implementation and Test phase, whichever will be the software coding, we will integrate that in different models and test it. Review phase, any product that is going to be launched outside, we will review that, are there some issues or changes in it or somewhere there is defect, so we will report that. Now we will see the Iterative Model’s advantages and disadvantages. Some functionality can be quickly developed in the Iterative Model. But what is the disadvantage? It Is that sometimes somewhere we want To develop a particular functionality, we need more resources. There is also one advantage that parallel development can be done. That means the requirements are coming and as per that the work is happening. So, both things are going parallel. Right? What is the disadvantage in Iterative Model? That there is a lot of management attention required. Where the work is happening as per the particular requirement or not. Very less cost is involved when the requirement is changed. Right? But what is its disadvantage is that somewhere a lot of time goes in architecture. Because the architecture was first developed on 4 requirements. Then after the requirements are changed, the complete architecture and whole communication of modules will be changed. Right? With every increment a new product is getting delivered and what is its disadvantage? We don’t know till when the product will be made and if it crashes somewhere. Right? And what is its second advantage? Issues and challenges will keep coming with every increment. So, in every increment we have to fix a new bug. And its disadvantage is that, somewhere we need a high skill resource, one experienced resource, which can see a particular product. Whenever we are launching a product, we are taking customer feedback, for every Iterative Model. What is the disadvantage? Somewhere the project that is there is getting a lot of dependence and it is going in the risk phase. So, that is its disadvantage. Now, we will see in the next topic about Agile Software.