Software Development Life Cycle Part 3


Video Script

The iterative development process, or the iterative development model breaks down software development into much smaller segments. This allows for a lot more change and variation to the development cycle. So the iterative development process works by working through many waterfalls. And so if you look at each one of these chunks here, each one of these stages, they’re pretty much the waterfall process. And so overall requirements are gathered, then we analyze those requirements develop, implement test, and this is a cycle right? In this case, our waterfall is circular so we can keep on trying Go Go, go, go go. And then we’re going to release a prototype or a version of our product. As we go through this each time a release, we demonstrate that to our customer. And get feedback and then we’ll work that back into our next cycle. And so we just keep on iterating this until we are doing our final release to our customer.

One more different developments that we want to talk about this time is actually proposed by Boehm, this combines prototyping and the waterfall development is very similar idea to iterative design. The spiral development model focuses on risk assessment and management by breaking projects into smaller parts, allowing for the evaluation and change as each part is individually finished. And so this works off of four main segments. So you are going to determine the objectives, alternatives and constraints of that particular iteration. So that small part, evaluate alternatives, identify and resolve those risks. So we want to try to match negates the risks because those risks, right, the more risk, the more cost is actually involved with the project. And then you’re going to develop and plan for the next iteration. So as you start to cycle out here, right, so you’re starting small, the center here, you’re going to start with very small projects, right. And as you complete those smaller projects, the base of the foundation of your software that’s going to slowly grow out, and you’re slowly going to introduce more things that are needed in the project, like different models, different prototypes, more testing, and the closer you get to the outside edge of the spiral, the closer you’re going to get to deployment. But this is again, right like iterative design, much more flexible, and overall, much more appropriate to what modern software actually lends itself to.

But even more so after this We actually come into something that’s very popular industry today called the Agile process. These methodologies that we’ve talked about so far were to being developed by software engineers and high level planning positions. A new philosophy was emerging from the rank and file developers which, as expressed in this Agile Manifesto, the manifesto reads as we are uncovering better ways of developing software, by doing it and helping others to do it. Through this work, we have come to value individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a plan. That is, while there is value in the items on the right, we value the items on the left more. So while agile is often thought of as, as a software engineering process By itself, it’s not. Rather it’s a guiding philosophy that can be applied in conjunction with many other software development approaches. That said, it clearly works better with something like iterative or spiral development or any other reactive styles of software engineering than the more rigid approaches that embodied the waterfall approach. And so as part of the reading, I’m going to actually ask that you go check out the Agile website and honor they have all the principles that are assessed with agile development and kind of embody what agile actually means.

But overall in the Agile process, you’ll typically see something like this agile as it stands right is the philosophy behind it as extreme flexibility. In this sense, you work off of mostly what we refer to as sprints. So these small Sprint’s will always have some sort of deliverable. product to the consumer or the customer. So it’s looks very similar to what we see with the software development lifecycle and a lot of the iterative or spiral processes where you brainstorm or gather requirements, you design prototype, develop, you QA. So you test and test and test and test. And then you deploy. And as you deploy, you do a little bit more testing, and you deliver that product to your customer. Or maybe you deliver that to the next person up in your organization. And all that feedback is then worked back into the next iteration into your next sprint. And so typically, what you’ll see with Agile process of the Agile process or Agile software development is that each sprint will focus on one or two small features of the software. And once that feature is actually completed, then the that particular developer will move on To the next sprint with the next development of either that same feature with modifications that were given to them by the consumer, or moving on to after completing that feature moving on to the next.

Another improvement that came in the mid 90s was the development of a suite of standardized diagrams for modeling software. The Unified Modeling Language, or UML. UML allowed for complex software systems to be diagram discussed and shared between developers and an easier to interpret form. Because before then there was no standard for documentation or not necessarily, but there was a lot of complex software being developed and each programmer would document and diagram in their own unique way. Just like what we would have, we have our own unique way of speaking and writing. Each developer had their own way. of not only just writing their own code, but also diagramming and and discussing about that code. And so UML offer a standardized way to actually share the overall structure interactions. Things like the activity or sequence or flow of the program among different developers, actually was someone who’s actually been trained with you to interpret and read UML could understand the software at a much higher level, a much deeper level, even without knowing how to actually program. But for now, this is going to conclude our discussion on software engineering, software development. There’s obviously a lot more here that we did not cover. In future classes we’ll take a much deeper dive into the architecture, modeling and development of software.