Category: sdlc

SDLC – Overview ”; Previous Next Software Development Life Cycle (SDLC) is a process used by the software industry to design, develop and test high quality softwares. The SDLC aims to produce a high-quality software that meets or exceeds customer expectations, reaches completion within times and cost estimates. SDLC is the acronym of Software Development Life Cycle. It is also called as Software Development Process. SDLC is a framework defining tasks performed at each step in the software development process. ISO/IEC 12207 is an international standard for software life-cycle processes. It aims to be the standard that defines all the tasks required for developing and maintaining software. What is SDLC? SDLC is a process followed for a software project, within a software organization. It consists of a detailed plan describing how to develop, maintain, replace and alter or enhance specific software. The life cycle defines a methodology for improving the quality of software and the overall development process. The following figure is a graphical representation of the various stages of a typical SDLC. A typical Software Development Life Cycle consists of the following stages − Stage 1: Planning and Requirement Analysis Requirement analysis is the most important and fundamental stage in SDLC. It is performed by the senior members of the team with inputs from the customer, the sales department, market surveys and domain experts in the industry. This information is then used to plan the basic project approach and to conduct product feasibility study in the economical, operational and technical areas. Planning for the quality assurance requirements and identification of the risks associated with the project is also done in the planning stage. The outcome of the technical feasibility study is to define the various technical approaches that can be followed to implement the project successfully with minimum risks. Stage 2: Defining Requirements Once the requirement analysis is done the next step is to clearly define and document the product requirements and get them approved from the customer or the market analysts. This is done through an SRS (Software Requirement Specification) document which consists of all the product requirements to be designed and developed during the project life cycle. Stage 3: Designing the Product Architecture SRS is the reference for product architects to come out with the best architecture for the product to be developed. Based on the requirements specified in SRS, usually more than one design approach for the product architecture is proposed and documented in a DDS – Design Document Specification. This DDS is reviewed by all the important stakeholders and based on various parameters as risk assessment, product robustness, design modularity, budget and time constraints, the best design approach is selected for the product. A design approach clearly defines all the architectural modules of the product along with its communication and data flow representation with the external and third party modules (if any). The internal design of all the modules of the proposed architecture should be clearly defined with the minutest of the details in DDS. Stage 4: Building or Developing the Product In this stage of SDLC the actual development starts and the product is built. The programming code is generated as per DDS during this stage. If the design is performed in a detailed and organized manner, code generation can be accomplished without much hassle. Developers must follow the coding guidelines defined by their organization and programming tools like compilers, interpreters, debuggers, etc. are used to generate the code. Different high level programming languages such as C, C++, Pascal, Java and PHP are used for coding. The programming language is chosen with respect to the type of software being developed. Stage 5: Testing the Product This stage is usually a subset of all the stages as in the modern SDLC models, the testing activities are mostly involved in all the stages of SDLC. However, this stage refers to the testing only stage of the product where product defects are reported, tracked, fixed and retested, until the product reaches the quality standards defined in the SRS. Stage 6: Deployment in the Market and Maintenance Once the product is tested and ready to be deployed it is released formally in the appropriate market. Sometimes product deployment happens in stages as per the business strategy of that organization. The product may first be released in a limited segment and tested in the real business environment (UAT- User acceptance testing). Then based on the feedback, the product may be released as it is or with suggested enhancements in the targeting market segment. After the product is released in the market, its maintenance is done for the existing customer base. SDLC Models There are various software development life cycle models defined and designed which are followed during the software development process. These models are also referred as Software Development Process Models”. Each process model follows a Series of steps unique to its type to ensure success in the process of software development. Following are the most important and popular SDLC models followed in the industry − Waterfall Model Iterative Model Spiral Model V-Model Big Bang Model Other related methodologies are Agile Model, RAD Model, Rapid Application Development and Prototyping Models. Print Page Previous Next Advertisements ”;

Discuss SDLC ”; Previous Next SDLC stands for Software Development Life Cycle. SDLC is a process that consists of a series of planned activities to develop or alter the Software Products. This tutorial will give you an overview of the SDLC basics, SDLC models available and their application in the industry. This tutorial also elaborates on other related methodologies like Agile, RAD and Prototyping. Print Page Previous Next Advertisements ”;

SDLC Tutorial PDF Version Quick Guide Resources Job Search Discussion SDLC stands for Software Development Life Cycle. SDLC is a process that consists of a series of planned activities to develop or alter the Software Products. This tutorial will give you an overview of the SDLC basics, SDLC models available and their application in the industry. This tutorial also elaborates on other related methodologies like Agile, RAD and Prototyping. Why to Learn SDLC? Software Development Life Cycle (SDLC) is a process used by the software industry to design, develop and test high quality softwares. The SDLC aims to produce a high-quality software that meets or exceeds customer expectations, reaches completion within times and cost estimates. SDLC is a process followed for a software project, within a software organization. It consists of a detailed plan describing how to develop, maintain, replace and alter or enhance specific software. The life cycle defines a methodology for improving the quality of software and the overall development process. SDLC is the acronym of Software Development Life Cycle. It is also called as Software Development Process. SDLC is a framework defining tasks performed at each step in the software development process. ISO/IEC 12207 is an international standard for software life-cycle processes. It aims to be the standard that defines all the tasks required for developing and maintaining software. SDLC Models There are various software development life cycle models defined and designed which are followed during the software development process. These models are also referred as Software Development Process Models. Each process model follows a Series of steps unique to its type to ensure success in the process of software development. Following are the most important and popular SDLC models followed in the industry − Waterfall Model Iterative Model Spiral Model V-Model Big Bang Model Other related methodologies are Agile Model, RAD Model, Rapid Application Development and Prototyping Models. Audience This tutorial is relevant to all those professionals contributing in any manner towards Software Product Development and its release. It is a handy reference for the quality stakeholders of a Software project and the program/project managers. By the end of this tutorial, the readers will develop a comprehensive understanding of SDLC and its related concepts and will be able to select and follow the right model for any given Software project. Prerequisites There are no specific prerequisites for this SDLC tutorial and any software professional can go through this tutorial to get a bigger picture of how the high-quality software applications and products are designed. A good understanding of programming or testing or project management will give you an added advantage and help you gain maximum from this tutorial. Print Page Previous Next Advertisements ”;

SDLC – RAD Model ”; Previous Next The RAD (Rapid Application Development) model is based on prototyping and iterative development with no specific planning involved. The process of writing the software itself involves the planning required for developing the product. Rapid Application Development focuses on gathering customer requirements through workshops or focus groups, early testing of the prototypes by the customer using iterative concept, reuse of the existing prototypes (components), continuous integration and rapid delivery. What is RAD? Rapid application development is a software development methodology that uses minimal planning in favor of rapid prototyping. A prototype is a working model that is functionally equivalent to a component of the product. In the RAD model, the functional modules are developed in parallel as prototypes and are integrated to make the complete product for faster product delivery. Since there is no detailed preplanning, it makes it easier to incorporate the changes within the development process. RAD projects follow iterative and incremental model and have small teams comprising of developers, domain experts, customer representatives and other IT resources working progressively on their component or prototype. The most important aspect for this model to be successful is to make sure that the prototypes developed are reusable. RAD Model Design RAD model distributes the analysis, design, build and test phases into a series of short, iterative development cycles. Following are the various phases of the RAD Model − Business Modelling The business model for the product under development is designed in terms of flow of information and the distribution of information between various business channels. A complete business analysis is performed to find the vital information for business, how it can be obtained, how and when is the information processed and what are the factors driving successful flow of information. Data Modelling The information gathered in the Business Modelling phase is reviewed and analyzed to form sets of data objects vital for the business. The attributes of all data sets is identified and defined. The relation between these data objects are established and defined in detail in relevance to the business model. Process Modelling The data object sets defined in the Data Modelling phase are converted to establish the business information flow needed to achieve specific business objectives as per the business model. The process model for any changes or enhancements to the data object sets is defined in this phase. Process descriptions for adding, deleting, retrieving or modifying a data object are given. Application Generation The actual system is built and coding is done by using automation tools to convert process and data models into actual prototypes. Testing and Turnover The overall testing time is reduced in the RAD model as the prototypes are independently tested during every iteration. However, the data flow and the interfaces between all the components need to be thoroughly tested with complete test coverage. Since most of the programming components have already been tested, it reduces the risk of any major issues. The following illustration describes the RAD Model in detail. RAD Model Vs Traditional SDLC The traditional SDLC follows a rigid process models with high emphasis on requirement analysis and gathering before the coding starts. It puts pressure on the customer to sign off the requirements before the project starts and the customer doesn’t get the feel of the product as there is no working build available for a long time. The customer may need some changes after he gets to see the software. However, the change process is quite rigid and it may not be feasible to incorporate major changes in the product in the traditional SDLC. The RAD model focuses on iterative and incremental delivery of working models to the customer. This results in rapid delivery to the customer and customer involvement during the complete development cycle of product reducing the risk of non-conformance with the actual user requirements. RAD Model – Application RAD model can be applied successfully to the projects in which clear modularization is possible. If the project cannot be broken into modules, RAD may fail. The following pointers describe the typical scenarios where RAD can be used − RAD should be used only when a system can be modularized to be delivered in an incremental manner. It should be used if there is a high availability of designers for Modelling. It should be used only if the budget permits use of automated code generating tools. RAD SDLC model should be chosen only if domain experts are available with relevant business knowledge. Should be used where the requirements change during the project and working prototypes are to be presented to customer in small iterations of 2-3 months. RAD Model – Pros and Cons RAD model enables rapid delivery as it reduces the overall development time due to the reusability of the components and parallel development. RAD works well only if high skilled engineers are available and the customer is also committed to achieve the targeted prototype in the given time frame. If there is commitment lacking on either side the model may fail. The advantages of the RAD Model are as follows − Changing requirements can be accommodated. Progress can be measured. Iteration time can be short with use of powerful RAD tools. Productivity with fewer people in a short time. Reduced development time. Increases reusability of components. Quick initial reviews occur. Encourages customer feedback. Integration from very beginning solves a lot of integration issues. The disadvantages of the RAD Model are as follows − Dependency on technically strong team members for identifying business requirements. Only system that can be modularized can be built using RAD. Requires highly skilled developers/designers. High dependency on Modelling skills. Inapplicable to cheaper projects as cost of Modelling and automated code generation is very high. Management complexity is more. Suitable for systems that are component based and scalable. Requires user involvement throughout the life cycle. Suitable for project requiring shorter development times. Print Page Previous

SDLC – Software Prototype Model ”; Previous Next The Software Prototyping refers to building software application prototypes which displays the functionality of the product under development, but may not actually hold the exact logic of the original software. Software prototyping is becoming very popular as a software development model, as it enables to understand customer requirements at an early stage of development. It helps get valuable feedback from the customer and helps software designers and developers understand about what exactly is expected from the product under development. What is Software Prototyping? Prototype is a working model of software with some limited functionality. The prototype does not always hold the exact logic used in the actual software application and is an extra effort to be considered under effort estimation. Prototyping is used to allow the users evaluate developer proposals and try them out before implementation. It also helps understand the requirements which are user specific and may not have been considered by the developer during product design. Following is a stepwise approach explained to design a software prototype. Basic Requirement Identification This step involves understanding the very basics product requirements especially in terms of user interface. The more intricate details of the internal design and external aspects like performance and security can be ignored at this stage. Developing the initial Prototype The initial Prototype is developed in this stage, where the very basic requirements are showcased and user interfaces are provided. These features may not exactly work in the same manner internally in the actual software developed. While, the workarounds are used to give the same look and feel to the customer in the prototype developed. Review of the Prototype The prototype developed is then presented to the customer and the other important stakeholders in the project. The feedback is collected in an organized manner and used for further enhancements in the product under development. Revise and Enhance the Prototype The feedback and the review comments are discussed during this stage and some negotiations happen with the customer based on factors like – time and budget constraints and technical feasibility of the actual implementation. The changes accepted are again incorporated in the new Prototype developed and the cycle repeats until the customer expectations are met. Prototypes can have horizontal or vertical dimensions. A Horizontal prototype displays the user interface for the product and gives a broader view of the entire system, without concentrating on internal functions. A Vertical prototype on the other side is a detailed elaboration of a specific function or a sub system in the product. The purpose of both horizontal and vertical prototype is different. Horizontal prototypes are used to get more information on the user interface level and the business requirements. It can even be presented in the sales demos to get business in the market. Vertical prototypes are technical in nature and are used to get details of the exact functioning of the sub systems. For example, database requirements, interaction and data processing loads in a given sub system. Software Prototyping – Types There are different types of software prototypes used in the industry. Following are the major software prototyping types used widely − Throwaway/Rapid Prototyping Throwaway prototyping is also called as rapid or close ended prototyping. This type of prototyping uses very little efforts with minimum requirement analysis to build a prototype. Once the actual requirements are understood, the prototype is discarded and the actual system is developed with a much clear understanding of user requirements. Evolutionary Prototyping Evolutionary prototyping also called as breadboard prototyping is based on building actual functional prototypes with minimal functionality in the beginning. The prototype developed forms the heart of the future prototypes on top of which the entire system is built. By using evolutionary prototyping, the well-understood requirements are included in the prototype and the requirements are added as and when they are understood. Incremental Prototyping Incremental prototyping refers to building multiple functional prototypes of the various sub-systems and then integrating all the available prototypes to form a complete system. Extreme Prototyping Extreme prototyping is used in the web development domain. It consists of three sequential phases. First, a basic prototype with all the existing pages is presented in the HTML format. Then the data processing is simulated using a prototype services layer. Finally, the services are implemented and integrated to the final prototype. This process is called Extreme Prototyping used to draw attention to the second phase of the process, where a fully functional UI is developed with very little regard to the actual services. Software Prototyping – Application Software Prototyping is most useful in development of systems having high level of user interactions such as online systems. Systems which need users to fill out forms or go through various screens before data is processed can use prototyping very effectively to give the exact look and feel even before the actual software is developed. Software that involves too much of data processing and most of the functionality is internal with very little user interface does not usually benefit from prototyping. Prototype development could be an extra overhead in such projects and may need lot of extra efforts. Software Prototyping – Pros and Cons Software prototyping is used in typical cases and the decision should be taken very carefully so that the efforts spent in building the prototype add considerable value to the final software developed. The model has its own pros and cons discussed as follows. The advantages of the Prototyping Model are as follows − Increased user involvement in the product even before its implementation. Since a working model of the system is displayed, the users get a better understanding of the system being developed. Reduces time and cost as the defects can be detected much earlier. Quicker user feedback is available leading to better solutions. Missing functionality can be identified easily. Confusing or difficult functions can be identified. The Disadvantages of the Prototyping Model are as follows − Risk of insufficient requirement

SDLC – V-Model ”; Previous Next The V-model is an SDLC model where execution of processes happens in a sequential manner in a V-shape. It is also known as Verification and Validation model. The V-Model is an extension of the waterfall model and is based on the association of a testing phase for each corresponding development stage. This means that for every single phase in the development cycle, there is a directly associated testing phase. This is a highly-disciplined model and the next phase starts only after completion of the previous phase. V-Model – Design Under the V-Model, the corresponding testing phase of the development phase is planned in parallel. So, there are Verification phases on one side of the ‘V’ and Validation phases on the other side. The Coding Phase joins the two sides of the V-Model. The following illustration depicts the different phases in a V-Model of the SDLC. V-Model – Verification Phases There are several Verification phases in the V-Model, each of these are explained in detail below. Business Requirement Analysis This is the first phase in the development cycle where the product requirements are understood from the customer’s perspective. This phase involves detailed communication with the customer to understand his expectations and exact requirement. This is a very important activity and needs to be managed well, as most of the customers are not sure about what exactly they need. The acceptance test design planning is done at this stage as business requirements can be used as an input for acceptance testing. System Design Once you have the clear and detailed product requirements, it is time to design the complete system. The system design will have the understanding and detailing the complete hardware and communication setup for the product under development. The system test plan is developed based on the system design. Doing this at an earlier stage leaves more time for the actual test execution later. Architectural Design Architectural specifications are understood and designed in this phase. Usually more than one technical approach is proposed and based on the technical and financial feasibility the final decision is taken. The system design is broken down further into modules taking up different functionality. This is also referred to as High Level Design (HLD). The data transfer and communication between the internal modules and with the outside world (other systems) is clearly understood and defined in this stage. With this information, integration tests can be designed and documented during this stage. Module Design In this phase, the detailed internal design for all the system modules is specified, referred to as Low Level Design (LLD). It is important that the design is compatible with the other modules in the system architecture and the other external systems. The unit tests are an essential part of any development process and helps eliminate the maximum faults and errors at a very early stage. These unit tests can be designed at this stage based on the internal module designs. Coding Phase The actual coding of the system modules designed in the design phase is taken up in the Coding phase. The best suitable programming language is decided based on the system and architectural requirements. The coding is performed based on the coding guidelines and standards. The code goes through numerous code reviews and is optimized for best performance before the final build is checked into the repository. Validation Phases The different Validation Phases in a V-Model are explained in detail below. Unit Testing Unit tests designed in the module design phase are executed on the code during this validation phase. Unit testing is the testing at code level and helps eliminate bugs at an early stage, though all defects cannot be uncovered by unit testing. Integration Testing Integration testing is associated with the architectural design phase. Integration tests are performed to test the coexistence and communication of the internal modules within the system. System Testing System testing is directly associated with the system design phase. System tests check the entire system functionality and the communication of the system under development with external systems. Most of the software and hardware compatibility issues can be uncovered during this system test execution. Acceptance Testing Acceptance testing is associated with the business requirement analysis phase and involves testing the product in user environment. Acceptance tests uncover the compatibility issues with the other systems available in the user environment. It also discovers the non-functional issues such as load and performance defects in the actual user environment. V- Model ─ Application V- Model application is almost the same as the waterfall model, as both the models are of sequential type. Requirements have to be very clear before the project starts, because it is usually expensive to go back and make changes. This model is used in the medical development field, as it is strictly a disciplined domain. The following pointers are some of the most suitable scenarios to use the V-Model application. Requirements are well defined, clearly documented and fixed. Product definition is stable. Technology is not dynamic and is well understood by the project team. There are no ambiguous or undefined requirements. The project is short. V-Model – Pros and Cons The advantage of the V-Model method is that it is very easy to understand and apply. The simplicity of this model also makes it easier to manage. The disadvantage is that the model is not flexible to changes and just in case there is a requirement change, which is very common in today’s dynamic world, it becomes very expensive to make the change. The advantages of the V-Model method are as follows − This is a highly-disciplined model and Phases are completed one at a time. Works well for smaller projects where requirements are very well understood. Simple and easy to understand and use. Easy to manage due to the rigidity of the model. Each phase has specific deliverables and a review process. The disadvantages of the V-Model method are as follows − High

SDLC – Big Bang Model ”; Previous Next The Big Bang model is an SDLC model where we do not follow any specific process. The development just starts with the required money and efforts as the input, and the output is the software developed which may or may not be as per customer requirement. This Big Bang Model does not follow a process/procedure and there is a very little planning required. Even the customer is not sure about what exactly he wants and the requirements are implemented on the fly without much analysis. Usually this model is followed for small projects where the development teams are very small. Big Bang Model ─ Design and Application The Big Bang Model comprises of focusing all the possible resources in the software development and coding, with very little or no planning. The requirements are understood and implemented as they come. Any changes required may or may not need to revamp the complete software. This model is ideal for small projects with one or two developers working together and is also useful for academic or practice projects. It is an ideal model for the product where requirements are not well understood and the final release date is not given. Big Bang Model – Pros and Cons The advantage of this Big Bang Model is that it is very simple and requires very little or no planning. Easy to manage and no formal procedure are required. However, the Big Bang Model is a very high risk model and changes in the requirements or misunderstood requirements may even lead to complete reversal or scraping of the project. It is ideal for repetitive or small projects with minimum risks. The advantages of the Big Bang Model are as follows − This is a very simple model Little or no planning required Easy to manage Very few resources required Gives flexibility to developers It is a good learning aid for new comers or students. The disadvantages of the Big Bang Model are as follows − Very High risk and uncertainty. Not a good model for complex and object-oriented projects. Poor model for long and ongoing projects. Can turn out to be very expensive if requirements are misunderstood. Print Page Previous Next Advertisements ”;