SOFTWARE TESTING TOOLS. Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details. The ComputersEasy Questions and Answers List: You can scroll through the BIG list of questions below OR you can click on one of the subsections below to jump to that. Software prototyping - Wikipedia. Software prototyping is the activity of creating prototypes of software applications, i. It is an activity that can occur in software development and is comparable to prototyping as known from other fields, such as mechanical engineering or manufacturing. A prototype typically simulates only a few aspects of, and may be completely different from, the final product. Prototyping has several benefits: The software designer and implementer can get valuable feedback from the users early in the project. The client and the contractor can compare if the software made matches the software specification, according to which the software program is built. It also allows the software engineer some insight into the accuracy of initial project estimates and whether the deadlines and milestones proposed can be successfully met. The degree of completeness and the techniques used in the prototyping have been in development and debate since its proposal in the early 1. Prototyping can also be used by end users to describe and prove requirements that have not been considered, and that can be a key factor in the commercial relationship between developers and their clients. Prototyping can also avoid the great expense and difficulty of changing a finished software product. The practice of prototyping is one of the points Frederick P. Brooks makes in his 1. The Mythical Man- Month and his 1. No Silver Bullet. An early example of large- scale software prototyping was the implementation of NYU's Ada/ED translator for the Ada programming language. The Environmental Compliance Program Area encompasses compliance related issues such as auditing, sources of regulations, executive orders, and policies applicable to.
The NYU Ada/ED system was the first validated Ada implementation, certified on April 1. Details, such as security, can typically be ignored. Develop Initial Prototype. The initial prototype is developed that includes only user interfaces. Negotiation about what is within the scope of the contract/product may be necessary. If changes are introduced then a repeat of steps #3 and #4 may be needed. Dimensions of prototypes. It provides a broad view of an entire system or subsystem, focusing on user interaction more than low- level system functionality, such as database access. Horizontal prototypes are useful for: Confirmation of user interface requirements and system scope,Demonstration version of the system to obtain buy- in from the business,Develop preliminary estimates of development time, cost and effort. Vertical prototype. It is useful for obtaining detailed requirements for a given function, with the following benefits: Refinement database design,Obtain information on data volumes and system interface needs, for network sizing and performance engineering,Clarify complex requirements by drilling down to actual system functionality. Types of prototyping. However, all the methods are in some way based on two major types of prototyping: Throwaway Prototyping and Evolutionary Prototyping. Throwaway prototyping. Throwaway or Rapid Prototyping refers to the creation of a model that will eventually be discarded rather than becoming part of the final delivered software. After preliminary requirements gathering is accomplished, a simple working model of the system is constructed to visually show the users what their requirements may look like when they are implemented into a finished system. It is also a Rapid Prototyping. Rapid Prototyping involved creating a working model of various parts of the system at a very early stage, after a relatively short investigation. The method used in building it is usually quite informal, the most important factor being the speed with which the model is provided. The model then becomes the starting point from which users can re- examine their expectations and clarify their requirements. When this has been achieved, the prototype model is 'thrown away', and the system is formally developed based on the identified requirements. If the users can get quick feedback on their requirements, they may be able to refine them early in the development of the software. Making changes early in the development lifecycle is extremely cost effective since there is nothing at that point to redo. If a project is changed after a considerable amount of work has been done then small changes could require large efforts to implement since software systems have many dependencies. Speed is crucial in implementing a throwaway prototype, since with a limited budget of time and money little can be expended on a prototype that will be discarded. Another strength of Throwaway Prototyping is its ability to construct interfaces that the users can test. The user interface is what the user sees as the system, and by seeing it in front of them, it is much easier to grasp how the system will work. Requirements can be identified, simulated, and tested far more quickly and cheaply when issues of evolve ability, maintainability, and software structure are ignored. This, in turn, leads to the accurate specification of requirements, and the subsequent construction of a valid and usable system from the user's perspective via conventional software development models. One method of creating a low fidelity Throwaway Prototype is Paper Prototyping. The prototype is implemented using paper and pencil, and thus mimics the function of the actual product, but does not look at all like it. Another method to easily build high fidelity Throwaway Prototypes is to use a GUI Builder and create a click dummy, a prototype that looks like the goal system, but does not provide any functionality. Not exactly the same as Throwaway Prototyping, but certainly in the same family, is the usage of storyboards, animatics or drawings. These are non- functional implementations but show how the system will look. Summary: In this approach the prototype is constructed with the idea that it will be discarded and the final system will be built from scratch. The steps in this approach are: Write preliminary requirements. Design the prototype. User experiences/uses the prototype, specifies new requirements. Repeat if necessary. Write the final requirements. Evolutionary prototyping. The main goal when using Evolutionary Prototyping is to build a very robust prototype in a structured manner and constantly refine it. The reason for this is that the Evolutionary prototype, when built, forms the heart of the new system, and the improvements and further requirements will be built. When developing a system using Evolutionary Prototyping, the system is continually refined and rebuilt. We make assumptions about the way business will be conducted and the technology base on which the business will be implemented. A plan is enacted to develop the capability, and, sooner or later, something resembling the envisioned system is delivered. Although they may not have all the features the users have planned, they may be used on an interim basis until the final system is delivered. The partial system is sent to customer sites. As users work with the system, they detect opportunities for new features and give requests for these features to developers. Developers then take these enhancement requests along with their own and use sound configuration- management practices to change the software- requirements specification, update the design, recode and retest. At the end the separate prototypes are merged in an overall design. By the help of incremental prototyping we can reduce the time gap between user and software developer. Extreme prototyping. Basically, it breaks down web development into three phases, each one based on the preceding one. The first phase is a static prototype that consists mainly of HTML pages. In the second phase, the screens are programmed and fully functional using a simulated services layer. In the third phase, the services are implemented. The process is called Extreme Prototyping to draw attention to the second phase of the process, where a fully functional UI is developed with very little regard to the services other than their contract. Advantages of prototyping. Because changes cost exponentially more to implement as they are detected later in development, the early determination of what the user really wants can result in faster and less expensive software. Since users know the problem domain better than anyone on the development team does, increased interaction can result in a final product that has greater tangible and intangible quality. The final product is more likely to satisfy the user's desire for look, feel and performance. Disadvantages of prototyping. This can lead to overlooking better solutions, preparation of incomplete specifications or the conversion of limited prototypes into poorly engineered final projects that are hard to maintain. Further, since a prototype is limited in functionality it may not scale well if the prototype is used as the basis of a final deliverable, which may not be noticed if developers are too focused on building a prototype as a model. User confusion of prototype and finished system: Users can begin to think that a prototype, intended to be thrown away, is actually a final system that merely needs to be finished or polished. Users can also become attached to features that were included in a prototype for consideration and then removed from the specification for a final system. If users are able to require all proposed features be included in the final system this can lead to conflict. Developer misunderstanding of user objectives: Developers may assume that users share their objectives (e. For example, user representatives attending Enterprise software (e. People. Soft) events may have seen demonstrations of . Users might believe they can demand auditing on every field, whereas developers might think this is feature creep because they have made assumptions about the extent of user requirements. If the developer has committed delivery before the user requirements were reviewed, developers are between a rock and a hard place, particularly if user management derives some advantage from their failure to implement requirements.
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