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SOFTWARE
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SOFTWARE

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  1. SOFTWARE • The part of computer which have collectionof computer programs, procedures, rules , associated documentation and data Which are collected for specific purpose. | | <document classification>

  2. Category of software • Simple software - A small program. - designed, developed, used by the same person. - no systematic approach is required. • Industrial strength software - use some systematic approach called programming systems. - used by different user in different platform - complexity is high. | | <document classification>

  3. SOFTWARE ENGINEERING: • it is systematic,disciplined, quantifiable approach to the development, maintenance of the software to ensure the best solution most economically | | <document classification>

  4. CHARACTERISTICS OF SOFTWARE. • 1. Software is developed - it is not manufacture. • 2. Software is highly malleable. • 3. Software does not "wear out". • 4. Most software is created from scratch and not assembled from existing component. | | <document classification>

  5. SOFTWARE MYTHS • 1 software is easy to change. • 2. Computer provide greater reliability than the devices they replace. • 3. Testing software or 'providing software correct can remove all the errors. • 4. Reusing software increase safety. • 5. Software with more feature is better software. | | <document classification>

  6. SOFTWARE PROBLEM : • 1)EXPENSIVE: • - software is labor intensive. • - productivity is measured in term of DLOC (deliverable lines of code) per person- month. • 2) LATE • 3) UNRELIABILITY • 4) REWORK AND IMPLEMENTATION | | <document classification>

  7. REASONS OF SOFTWARE PROCESS FAIL: • 1. Not enough time • 2. Lack of knowledge • 3. Wrong motivations • 4. Insufficient commitment | | <document classification>

  8. QUALITIES OF SOFTWARE PRODUCT • CORRECTNESS: • Software which satisfies it’s functional requirement and user objective. • More accurate the requirement specification ,more accurate the software will be. • RELIABILITY: • The degree to which the system performs its intended functions over time. | | <document classification>

  9. MAINTAINABILITYThe ease with which the program errors are detected and removed.PORTABILITYThe ease of transporting a program from one hardware configuration to another.TESTABILITYThe effort required to test a program to ensure its correct performance. | | <document classification>

  10. ROBUSTNESS :Software must accommodate any unforeseen, sudden change in the environment .USER FRIENDLINESSThe efforts required to understand and operate a system.It is the measure of an effort required to configure, learn, use the software.VERIFIABILITYA software is verifiable if it’s properties such as performance , correctness etc. can be verified easily. | | <document classification>

  11. MODULARITY • A system that is composed of modules is called modular system. Advantage of using modular design: • decomposition • understanding | | <document classification>

  12. FUNDAMENTAL PROBLEM OF SOFTWARE ENGINEERING : • THE PROBLEM OF SCALE : • Small software will not work for the large system. • To change small to large system requires formal method of software development as well as the formal method of project management | | <document classification>

  13. PROBLEM of CSQ(cost,schedule,quality) : • COST : • - The cost of developing a system is the cost of resources . • - the cost of manpower spent on the project. • SCHEDULE : • Business trend require that the cycle time from the accept to delivery of a product should be small. | | <document classification>

  14. QUALITY :- qualities related to the operation of the system - qualities related to the maintenance | | <document classification>

  15. S/W ENGINEERING PARADIGM • It is essentially a set of steps thatcomprisesof methods ,tools and procedures. | | <document classification>

  16. COMPONENT OF SOFTWARE PROCESS • Development process • Project management process | | <document classification>

  17. SOFTAWARE PROCESS • The process that deals with the technical and management issues of software development. | | <document classification>

  18. TWO CATEGORIES OF PROCESS MODELS • NON SOFTWARE ENGG. PROCESSS MODEL • BUSINESS PROCESS MODEL • SOCIAL PROCESS MODEL • TRAINING MODEL These process also effect the software development activity but are beyond the purview of software engineering. | | <document classification>

  19. SOFTWARE DEVELOPMENT LIFE CYCLE • The evolution of software development represents the cycle of activities involved in the development ,use and maintenance of software systems. • The software life cycle are characterised into two part • - descriptive How the software system should be developed. • - prescriptive How software system are actually developed. | | <document classification>

  20. Three basic type of entities that Software engineering deals • PROCESES Specifies a method of developing software. • PROJECT It is a development project in which a software process is used. • PRODUCTS Software product are the outcomes of a software project . | | <document classification>

  21. session 2 Process model | | <document classification>

  22. THE SYSTEM DEVELOPMENT LIFE CYCLE • The set of activities that analysts ,designers and users carry out to develop and implement an information system | | <document classification>

  23. The SDLC consists of following phases Preliminary Investigation : Finding problem or opportunity for improving an information system or a procedure. | | <document classification>

  24. Analysis of system requirement • Analysis is a detailed study of the various operation performed by a system and their relationships within and outside of the system. • Data analysis on the available files, decision points and transaction handled by the present system. | | <document classification>

  25. Feasibility Study • Evaluation of existing system whether the system is feasible economically, technically, by technique and time etc. To decide either to go ahead with the project or to drop it. | | <document classification>

  26. Feasibility study is done to find out whether for the system that it is proposed ,it will be : Possible:(to build it with the given technology and resources) Affordable: (given the time and cost constraint of the organization) Acceptable: for use by the eventual users of the system) | | <document classification>

  27. DIFFERENT TYPE OF FEASIBILITY • TECHNICAL FEASIBILITY. • OPERRATIONAL FEASIBILITY. • ECHONOMIVAL FEASIBILITY. • TIME FEASIBILITY. • SOCIAL FEASIBILITY. • MANAGEMENT FEASIBILITY. • LEAGAL FEASIBILITY. • TECHNICAL FEASIBILITY. | | <document classification>

  28. OPERATIONAL FEASIBILITY • It is mainly related to human organizational and political aspect. • The point to be considered are ; • What changes will be brought with the system? • What new skills will be required? • What organization structures are distributed? | | <document classification>

  29. ECONOMIC FEASIBILITY • The following category of cost would need to be considered. • procurement cost – include cost of equipment purchase, cost of site preparation ,etc. • Start-up cost : include cost of system software, communication equipment, cost of recruiting manpower. | | <document classification>

  30. Project costs – include actual development cost of the software, training cost, datapreparation,conversioncost.Ongoing cost – it takes time and money to keep the system going even after it is implemented. | | <document classification>

  31. SOCIAL FEASIBILITY • Social feasibility is a determination of whether a proposed project will be acceptable to the people or not. | | <document classification>

  32. MANAGEMENT FEASIBILITY • It is a determination of whether a proposed project will be acceptable to management . | | <document classification>

  33. LEGAL FEASIBILITY • Legal feasibility is a determination of whether a proposed project infringes ,violation, contracts or liabilities. | | <document classification>

  34. Design of system • It describes a final system and process by which it is developed. • It refers to the technical specifications that will be applied in implementing the candidate system. | | <document classification>

  35. TestingThe system is used experimentally to ensure that the software does not fail. Implementation It is the process of having system personnel check out and put new equipment into use ,train persons ,install the new application and construct any files of data needed to use it. | | <document classification>

  36. Post-implementation ,maintenance and evaluation • After the system is implemented and conversion is completed ,a review should be conducted to determine whether the system is meeting expectations and where improvements are needed . • It review measures the system performance against pre-defined requirements. | | <document classification>

  37. SOFTWARE ENGG. PROCCESS MODELS • 1 Water fall model • 2. Prototype model • 3. Iterative enhancement model • 4. The spiral model | | <document classification>

  38. WATER FALL MODEL : A sequence of descending step. The essence of this models is that the process of software development consist of a set of distinct phases. • - REQUIREMENT ANALYSIS & SPECIFICATION • - SYSTEM DESIGN • - DETAILED DEIGN • - CODING & UNIT TESTING • - INTEGRATION & SYSTEM TESTING • - OPERATION & INTEGRATION | | <document classification>

  39. The Linear Model | | <document classification>

  40. LIMITATION OF WATER FALL MODEL • This model is suitable to automate for which all requirements are known before the design starts. • The water fall model does not accommodate times. • Water fall model is document driven. • It does not incorporate any kind of risk assessment. | | <document classification>

  41. PROTOTYPING MODEL • it is well suited for projects where the requirements are hard to determine. • it serves as a mechanism for identifying software requirements. • it is an excellent technique for reducing risks associated with a project. | | <document classification>

  42. REQUIREMENT ANALYSIS Refinement of requirement as per suggestion DESIGN Quick design CODE implement TEST Customer evolution OPERATION AND MAINTENANCE | | <document classification>

  43. Prototype Model Prototyping RAD | | <document classification>

  44. Prototype reduce S/W Development cost • Reduce the cost of later phases of the product development. • The final system developed will be more closer to the actual requirement because the user and developer gets involved in refining the system. • Requirement obtained after having the working experience with the prototype tends to be more stable. | | <document classification>

  45. LIMITATION OF PROTOTYPE MODEL • * Limited functional capabilities • * low relaibility • * untested performance | | <document classification>

  46. ITERATIVE ENHANCEMENT MODEL • The iterative model combines the features of both waterfall and prototype model. • it supports the increamental building of the new system. • this model can be useful if the core of the application is well understood and increments can be easily defined and negotiated . • In client-oriented projects , it is an advantage to the client can pay to the projects in installments . • the potential danger of this method is that the iteration may never end the user may never really get the "final" product . | | <document classification>

  47. The Incremental Model | | <document classification>

  48. THE SPIRAL MODEL • This model was proposed by barry boem in 1988. • -it incorporates the elements of the prototype driven approach along with the classic software life cycle. | | <document classification>

  49. The four major activites of each spiral are represented by the four quadrants : • PLANNING – determination of objectives,alternatives and constraints. • RISK ANALYSIS – analysis of alternatives and identification/resolving of risks. • ENGINEERING - Development of the next level product • CUSTOMER EVALUTION - Assessment of the result of re-engineering. | | <document classification>

  50. Determine objectives alternatives ,constraint Risk analysis based on customer reaction commitment Concept of operation software req | | <document classification>