Phases Of System Development Life Cycle Information Technology Essay

Phases Of body Development disembodied spirit calendar method of birth control Information Technology Es show constitution learning action steering wheel means combination of various activities. In other words we provoke say that various activities put together atomic number 18 referred as ashes knowledge sustenance cycle. In the transcription digest and Design terminology, the t processk development action sentence cycle means softw be development life cycle.Following are the different anatomys of computer software development cycleSystem charterFeasibility force fieldSystem abridgmentSystem human bodyCoding testImplementation aidThe different manakins of software development life cycle is sh receive in Fig.29.1Different phases of Software development Life CyclePHASES OF SYSTEM DEVELOPMENT LIFE CYCLELet us now describe the different phases and the related activities of musical arrangement of rules development life cycle in detail.(a) System StudySystem stu dy is the send-off stage of form development life cycle. This gives a clear register of what echtly the physical placement is? In practice, the organisation study is do in two phases. In the first phase, the preliminary survey of the placement is d oneness which helps in identifying the scope of the system. The second phase of the system study is more select and in-depth study in which the identification of exploiters requirement and the limitations and occupations of the birth system are studied. afterwards completing the system study, a system proposal is prepared by the System Analyst (who studies the system) and placed earlier the user. The proposed system contains the findings of the present system and recommendations to overcome the limitations and problems of the present system in the light of the users requirements.To describe the system study phase more analytically, we would say that system study phase passes through the hobby stepsproblem identification and check initiationbackground analysisinference or findings(b) Feasibility StudyOn the basis of result of the initial study, feasibleness study takes place. The feasibility study is basically the canvass of the proposed system in the light of its workability, meeting users requirements, effective use of resources and .of course, the cost effectiveness. The main tendency of feasibility study is non to solve the problem but to secure the scope. In the mould of feasibility study, the cost and benefits are estimated with greater accuracy.(c) System AnalysisAssuming that a smart system is to be developed, the sideline(a) phase is system analysis. Analysis involved a detailed study of the current system, leading to specifications of a refreshing system. Analysis is a detailed study of various operations performed by a system and their relationships at bottom and out(a)side the system. During analysis, information are collected on the available files, finis points and transacti ons handled by the present system. Interviews, on-site observation and questionnaire are the tools apply for system analysis. Using the following steps it becomes easy to draw the exact boundary of the new system under considerationKeeping in view the problems and new requirementsWorkout the pros and cons including new areas of the systemAll procedures, requirements mustiness be analyzed and documented in the form of detailed data flow plots (DFDs), data dictionary, logical data structures and miniature specifications. System Analysis also includes sub-dividing of complex process involving the entire system, identification of data stemma and manual processes.The main points to be discussed in system analysis areSpecification of what the new system is to accomplish based on the user requirements.Functional hierarchy showing the acts to be performed by the new system and their relationship with apiece other.Function network which are similar to function hierarchy but they high light those functions which are common to more than one procedure.List of attributes of the entities these are the data items which need to be held about distributively entity (record)(d) System DesignBased on the user requirements and the detailed analysis of a new system, the new system must be imageed. This is the phase of system designing. It is a most crucial phase in the development of a system. Normally, the design proceeds in two stagespreliminary or frequent design anatomical structure or detailed design exploratory or general design In the preliminary or general design, the features of the new system are specified. The costs of implementing these features and the benefits to be derived are estimated. If the visualize is still considered to be feasible, we move to the detailed design stage.Structure or Detailed design In the detailed design stage, estimator orient work begins in earnest. At this stage, the design of the system becomes more structured. Structure desig n is a blue print of a figurer system solution to a given problem having the same components and inter-relationship among the same components as the original problem. Input, output and processing specifications are drawn up in detail. In the design stage, the programming language and the platform in which the new system will tie are also decided.There are several tools and techniques use for designing. These tools and techniques areFlowchartData flow diagram (DFDs)Data dictionaryStructured English purpose tableDecision tree(e) Coding by and by designing the new system, the whole system is postulate to be converted into computer understanding language. Coding the new system into computer programming language does this. It is an important stage where the be procedures are transformed into control specifications by the help of a computer language. This is also called the programming phase in which the programmer converts the program specifications into computer instructions, which w e refer as programs. The programs coordinate the data movements and control the entire process in a system.It is generally felt that the programs must be standard in nature. This helps in fast development, maintenance and future castrate, if required.(f) Testing ahead actually implementing the new system into operations, a test run of the system is done removing all the bugs, if any. It is an important phase of a successful system. After codifying the whole programs of the system, a test plan should be developed and run on a given set of test data. The output of the test run should match the expected results.Using the test data following test run are carried outUnit testSystem testUnit test When the programs bring on been coded and compiled and brought to working conditions, they must be individually tested with the prepared test data. Any undesirable calamity must be noted and debugged (error corrections).System Test After carrying out the unit test for each of the programs of the system and when errors are removed, then system test is done. At this stage the test is done on actual data. The complete system is executed on the actual data. At each stage of the execution, the results or output of the system is analyzed. During the result analysis, it may be found that the outputs are not matching the expected out of the system. In such case, the errors in the particular programs are identified and are restore and further tested for the expected output.When it is ensured that the system is running error-free, the users are called with their own actual data so that the system could be shown running as per their requirements.(g) ImplementationAfter having the user acceptance of the new system developed, the slaying phase begins. Implementation is the stage of a project during which theory is cancelled into practice. During this phase, all the programs of the system are loaded onto the users computer. After loading the system, bringing up of the users starts . Main topics of such type of training areHow to execute the computer softwareHow to enter the dataHow to process the data (processing details)How to take out the reportsAfter the users are trained about the computerized system, manual working has to shift from manual to computerized working. The following two strategies are followed for running the systemParallel run In such run for a certain defined period, twain the systems i.e. computerized and manual are executed in parallel. This strategy is helpful because of the followingManual results can be compared with the results of the computerized system.Failure of the computerized system at the premature stage, does not affect the working of the organization, because the manual system continues to work, as it used to do.Pilot run In this type of run, the new system is installed in parts. Some part of the new system is installed first and executed successfully for considerable time period. When the results are found satisfactory th en alone other parts are implemented. This strategy builds the confidence and the errors are traced easily.(h) MaintenanceMaintenance is necessary to eliminate errors in the system during its working life and to tune the system to any variations in its working environment. It has been seen that there are always some errors found in the system that must be noted and corrected. It also means the review article of the system from time to time. The review of the system is done forknowing the full capabilities of the systemknowing the required changes or the additional requirementsstudying the performanceIf a major change to a system is needed, a new project may hold in to be set up to carry out the change. The new project will then proceed through all the above life cycle phases.Task 4.2Life Cycle ModelsWaterfall mannequinPrototyping modelEvolutionary modelThe spiral modelFormal developmentincremental developmentRapid application modelV-Shaped modelRequirements analysis explanatio nintegration and Software interrogationSoftware dDesignImplementation and unit testingOperation and MaintenanceWaterfall ModelFigure 7This takes the basics process activities of specification, development, validation and evolution and represents them as separate process phase such as requirement specification, software design, performance and testing and so on.Requirement Analysis and DefinitionThe systems services, constraints and goals are established by source with the software users. They are then defined in detail and administer as a software specification.how the current software works and what it doesProducing a detailed model in subject terms of what the new software will do and how it will work.Producing a high-level description of new softwareSoftware DesignThe software design process partitions the requirements to every hardware or software system. It establishes overall software architecture. Software design involves identifying and describing the fundamental softwar e system abstraction and their relationships.Implementation and Unit TestingDuring this stage, the software design is realized as a set of programs or program units. Unit testing involves verifying that each unit meets its specification.Integration and Software TestingThe individual program units or programs are structured and tested as complete software to ensure that the software requirements have been met. After testing, the software system is delivered to the customer.Operation and MaintenanceNormally this is the drawn-out life cycle phase. The software is installed and put into practical use. Maintenance involves correcting errors which were not discovered in earlier stages of the life cycle improving the implementation of the software units and enhancing the softwares services as new requirement are discovered.