No silver bullet summary (paper)
- 1. No silver bullet Group member: Shakeel khan InamUllah shah Abasyn university Islamabad
- 2. Introduction No silver bullet There is no straight forward way on which we go and sure that we got the extreme solution of the problem. OR There are no single SDLC or methodology which we follow and say that, this the best way and technique to follow for solving the software problem.
- 3. Essence and Accidents There are two problems facing software engineering. 1. essence: difficulties inherent in the nature of software. e.g. complex conceptual constructs( algorithm, data sets, function, relationship 2. accidents: difficulties related to the production of software. e.g. representing the constructs in programming language.
- 4. The Essence Brooks divides the essence into four subcategories 1. complexity 2. conformity 3. changeability 4. invisibility
- 5. complexity • No two parts are alike. • Huge number of states. • Complexity grows nonlinearly with size. • Can’t know the whole domain, process, or system. • Introduces technical and managerial problems leading to unreliability. • No two part are alike. • Complete structure and function.
- 6. Cont… Problems resulting from complexity • difficult team communication. • product flaws, cost overruns. • personnel turnover (loss of knowledge) . • project overview is difficult.
- 7. Conformity • Most of the time software systems have to interface with an existing system. • Even for a new system, the perception is that, it is easier to make software interfaces conform to other parts of the system . • We need not to change the whole existing system because of new software. • May be difficult to change the environment, however if the environment changes, the software system is expected to adapt.
- 8. Changeability • The nature of software change is another essential problem. • When software changes, unlike other entities, typically it is the function being modified. Because software is relatively easy to change, it changes often. • Since software is easy to change software gets changed frequently and deviates from the initial design, adding new features , supporting new hardware.
- 9. Invisibility • The code is invisible. There’s only the external input/output view. • There is no simple geometric representation for software. • Structure is terribly complex and hidden. • Software does not have one map or graph, it will have multiple maps and graphs. • But There is nothing physical to visualize, it is hard to see an abstract concept.
- 10. Past breakthroughs solved accidental difficulties High level language It allows that some types on data structures, operation, classes etc. to be used by any machine. Programmers don’t have to develop software for individual machines. Powerful stroke for software productivity, reliability, & simplicity . Removed the low level complexities. Time sharing Increased turnaround time and productivity of programmer. Improvement is not as much as that of high-level language. System response time is no longer an issue. Programs run faster because of the high-level languages.
- 11. Hopes for the silver Ada and other high-level languages Ada high-level computer programming language used chiefly in real-time computerized control systems. Ada programming language and high-level languages are promising to tackle some of the issues experienced in software engineering, Ada was specifically designed for system functions where overall system efficiency and reliability is vital.
- 12. Cont… Object-oriented programming Its two important concepts, abstract data types and hierarchical types, represent real advances in the art of building software. Helps in design, but do not solve design complexity Problem. Artificial intelligence It is computer hardware and software processes which choose the best solution in a given problem likely to be chosen by humans e.g. human and hardware interaction .
- 13. Cont… Expert System Every software system should be designed and built in such a manner that it would be able to test and diagnose itself when it malfunctions, However this would not be an easy task to implement. Building an expert system would require very knowledgeable programmers which could build a general system to solve multiple complex tasks.
- 14. Cont… Automatic Programming Generation of a program from problem specification. It is essential to have software systems that are able to program themselves, and write program solutions of problem from a problem statement automatically. Graphical programming presentation of software functions in a graphical manner like flow charts . But problem is diagrams tend to be bigger than a normal screen size of a computer. More fundamentally, software is very difficult to visualize.
- 15. Cont.. Program verification Program verification is where most programmers spend time and it is one of the most important steps in a software life-cycle. Verifying a program before the testing phase can eliminate a lot of anomalies, it could even reduce the time spent on testing the actual software because each requirement would be verified before being implemented. Environments and tools Given the powerful computers available in this modern day to surely facilitate software development. But magical enhancement thus cannot be expected.
- 16. Attacks the essence Buys vs Build Good generalized software tools (mass market software for writing, drawing, file management, and spreadsheets) can have a big impact on productivity. In the past 20 years, a large number of open source tools have reinforced the value of reusing existing software. Refinement and rapid Programming The hardest part of software is determining exactly what to build. Must show product to customer to get complete specification .Need for iterative feedback.
- 17. Cont… Incremental development The most successful software is grown in stages, not developed in a single stage of software construction. The approach necessitates top-down design, thus allowing easy backtracking and detecting fundamental defects as early as possible. Great Designer Great designers are orders-of-magnitude better at creating small and cheap code quickly. These designers should be treated like star managers, and should be identified quickly.
- 18. Conclusion • No one advance will give a great improvement by which the accidental difficulties can be solved. • Even if we remove all accidental difficulties still at its essence software development is difficult. • There is still a hope for silver for solving software related problems and thus for the betterment of later issues. • The real problem of software engineering is dealing with ever-changing requirements. • No model, method, artifact, or tool offered to date has succeeded to overcome this problem.