tersenotes - Tumblr blog

[tersenotes]

Incremental Model

The software is developed in an incremental and iterative way. The requirements are collected upfront and split into small increments or slices. Read the full article

[tersenotes]

Major difficulties of waterfall-based model

The following are based on the waterfall model: Classical waterfall modelIterative waterfall modelV model.Prototype model What are the major difficulties of the waterfall based models? Difficulty in accommodating change requests during development. In reality, 40% of the requirements change during development.High cost incurred in developing custom applications.Heavyweight processes:Lots of documentations are produced at each phase and it has been reviewed.It has been noticed that 50% of the time, people involved in documentations.Requirements for the system are determined and documented at the start are assumed to be fixed from that point on. And entire long term planning is made based on the initial frozen requirements. Fred Brooks: The assumption that one can specify a satisfactory system in advance, get bids for its construction, have it built, and install it. This assumption is fundamentally wrong and many software acquisition problems spring from this. In response to the shortcoming of the waterfall model, these models were proposed: Incremental modelRapid Application Development modelEvolutionary model Detail description and discussion (Optional) There are some severe shortcomings of the waterfall model because of which they are not as popular as they were about 30-40 years back. The main problem that is being faced is that the type of project that is being handled are different from those that were handled 30-40 years back. Now, the projects are short and the code is not written from scratch because a lot of code is being reused and only small modifications and tailoring is done which we called as service-oriented software. The major difficulties of the waterfall-based models: The first problem is that there is no way change requests can be handled. The requirements are gathered up front and documented, it is assumed that this will not change, and then the plan is made based on these documented requirements, the design is done on these requirements and then coding and testing is done with respective these requirements. But then, in reality, the present projects the requirements keep on changing as development proceeds. Typically about 40 to 50 percent of the requirements change after the initial requirement specification. The second problem is that many of the projects now are for customizing applications as already mentioned about the service-oriented software where the organization has some software and would tailor it for the specific needs of another customer. If we use the waterfall model for these custom applications there will be a huge cost because the entire thing has to be documented, specification laid out, design, and so on. The third problem is that the waterfall model is called a heavyweight process because a lot of documentation is produced as part of the process. These are starting from requirement specification, the reviews, review results, the design various types of plans everything is to be documented and that is the reason these are called heavyweight processes. And it is estimated the typically 50 percent of the effort by a development team goes towards creating documents and naturally the project costs increase and project delays. Reference: Fundamentals of Software Engineering Book by Rajib Mall.Wikipedia Read the full article

[tersenotes]

Terse Notes - A technical blog

[tersenotes]

Prototype Model

What is Prototype Model. What is the advantages of using prototype model over iterative waterfall model?

In the prototype model, before starting the actual development, a working prototype of the system first built. A prototype is a toy implementation of a system with limited functional capabilities, low reliability, and inefficient performance.

Why prototype needs to be constructed?

Sometimes the customer does not know what exactly they want, to resolve their confusion and understand their…

[tersenotes]

What is the phase containment of error in software process life cycle?

What is the phase containment of error in software process life cycle?

The principle of detecting errors as close to its point of introduction as possible is known as Phase containment of errors.

A defect that will get noticed during the testing phase and we need to go back to the design phase or maybe the requirement analysis phase and then fix that defect. The defects must be detected and fixed in the same phase to lower the overall development cost and time.…

[tersenotes]

V model (Verification and Validation Model)

V model (Verification and Validation Model)

It is a variant of the waterfall model. It mainly emphasizes verification and validation. Verification and validation activities are spread over the entire life cycle. In each phase of development, testing activities are planned in parallel with development. The diagrammatic representation of the V model looks like a V and that is the reason why it is called a V model.

Strength of V Model:

[tersenotes]

What is verification and validation in Software Testing?

A short and terse notes on difference between verification and validation in Software Testing.

Verification is the process of determining whether the output of one phase of development conforms to its previous phase. It is concerned with phase containment of errors. The code review, simulation, unit testing, and integration testing are the mechanisms through which verification can be performed.

Validation is the process of determining whether a fully developed system conforms to its…

[tersenotes]

Iterative waterfall model

A terse notes on the iterative waterfall model - Software engineering.

Limitation of Classical waterfall model:

The classical waterfall model is idealistic, it assumes that no defect is introduced during any development activity. However, in practice, defects do get introduced in almost every phase of the life cycle and defects usually get detected much later in the life cycle.

For example A design defect might go unnoticed till the coding or testing phase.…

[tersenotes]

Project Management Body of Knowledge (PMBOK)

Project Management Body of Knowledge (PMBOK)

PMBOK

The PMBOK is a very popular project management standard, it is the Project Management Body of Knowledge, it is a dominant project management standard used widely across various projects. The PMBOK basically consists of several terminologies and guidelines and this has been documented in the form of a book as you can see here Project Management Book of Knowledge PMBOK Guide. It is…

[tersenotes]

Software Project Management Standards

Software Project Management Standards

There are several guidelines that have come up for the project manager to carry out the project management processes. There are two types of project management standards.

Off-the-shelf project management standards.

In-house project management standards.

In the off-the-shelf project management standards, the popular ones are PMBOK (Project Manager Book of Knowledge), PRINCE2(Projects IN…

[tersenotes]

Jargons in software project management

Jargons in software project management

What is a project?

A project is a temporary endeavor undertaken to create a unique product, service, or result (PMBOK Guide, fifth edition, 2012). A set of activities undertaken within a defined time period in order to meet a specific set of goals/objectives within a budget. (Plan activity, bounded time period, associated budget)

A project generally exhibits most of the following properties:

[tersenotes]

Why software project management is hard?

Why software project management is hard?

To understand how software project management is hard. We will first look at how software project is different from non-software projects?

Software is intangible and it is invisible till it is ready and runs. It might be possible that lots of code has written but don’t know whether it is going in right direction or not. So, something that is invisible is really difficult to manage.

Large change…

[tersenotes]

What is project portfolio management?

What is project portfolio management?

We will decompose and explore individual words of project portfolio management (PPM) to get a better understanding of entire term.

Starting with Portfolio: It means a briefcase. However, when are talking about finance then a portfolio tells a collection of assets held by an individual or an organization. In the same way, when we are talking about project development companies portfolios, it…

[tersenotes]

Classical waterfall model

The classical waterfall model is elegant and intuitive. However, it is not a practical model in the sense that it cannot be used in actual software development projects. Thus, this model can be considered to be a theoretical way of developing software. The classical waterfall model divides lifecycle into following phases.

Feasibility Study

Requirements Analysis and Specification

Design

Coding and…

[tersenotes]

Writing an effective business case

Writing an effective business case

A business case captures the reasoning for initiating a project or task. It is often presented in a well-structured written document, but may also come in the form of a short verbal agreement or presentation. By Wikipedia.

In this article, we will explain the preparation of an effective business case after the completion of a feasibility study by the business analyst. The outcome of the…

[tersenotes]

Why model life cycle?

Why model life cycle?

To understand why we need to follow a life cycle model for the development of a software product. I would like to introduce a general software development life cycle or a process model.

A life cycle model is a description and diagrammatic model of the software life cycle. Its goal is to identifies all the activities undertaken during product development and establishes a precedence ordering…

[tersenotes]

Difference between the exploratory style and modern software development practices

Difference between the exploratory style and modern software development practices

Exploratory Style: It is called a build and fix style. It only focuses on detecting errors at the testing phase and quickly fixes it and does the same again and again till the time all the errors are being fixed for that release.

We still follow this approach, when a project or assignment is handled by a single developer, the code sizes are manageable and within the grasp on an individual.…