Introduction to software Enginering
0 likes68 views
The document discusses the history of software development problems that led to the emergence of software engineering. In the 1940s, software was developed without standardized processes, resulting in poor quality, budget overruns, and unreliable software. This "software crisis" demonstrated the need for software engineering - a systematic and disciplined approach to software development focused on producing high-quality, on-budget products. The document then defines what software and hardware are, compares their failure rates over time, and provides examples of failed software projects to further illustrate the risks of an unengineered approach.
Introduction to software Enginering
- 1. Software Engineering INTRODUCTION R. Aswin Herbert Sathsih.,MCA.,MPhil,(PhD)
- 2. Software Crisis • 1940’s - Software Development is not an independent process. • Person developed - Executed, Tested, Debugged and Maintained. • Instruction written in assembly language. • Final product – Poor Quality. • Time and Money spent on maintaining the software,
- 3. Contd…Software Crisis Examples • Development teams exceeding the budget. • Late delivery of software. • Poor Quality. • User requirements not completely supported by the software. • Difficult maintenance. • Unreliable software.
- 7. What is a Software ? • Software can be defined as a set of instruction which when executed on a computer accepts the inputs and after doing required computations, produces the output or result as per users requirements. • It is also accompanied by user manual so as to understand so as to understand the features and working of the software.
- 8. Software consist of … • Source code. • Executables • User Manuals • Requirement Analysis and Design Documents • Installation Manuals
- 11. Contd… Hardware • Bath tub Curve. • Is manufactured/ Assembled. • Wear out.
- 13. Contd… Software • It is developed or engineered • Multiple copies can be produced • Flexible and easily accommodate the changes • Retire than wear out
- 14. Examples of Failed Projects • June 1996 – Anane 5 launcher exploded after 40 seconds of take off.( 4 km) • Loss – 400 million • Error – Overflow in the conversion from 64 bit floating point number to 16 bit signed integer.
- 15. Contd… Examples • 1980 – Sperry Corporations in US – automate income tax forms hired Internal Revenue Service. • Loss – 103 million ( Development cost ) + 90 million • Error – Inefficient to handle the load • Result – 40.2 million interest paid to customers
- 16. Contd… Examples • Therac-25 Radiation Therapy and X-Ray Machine. • Error -Malfunctioning of arrow keys which were not programmed. • Result – High dose of radiations was given to patients whereas only low levels are required. • Loss - Killed several patients –
- 17. Contd… Examples • Ministry of Agriculture in UK undergone a loss of 12 million pound. • Space shuttle Columbia was delayed by three years – Millions of dollars loss. • Software errors
- 21. Software Engineering … • Strategy for producing quality product. • Economic • Reliable • Efficient Or Systematic transformation of a problem into a working software solutions.
- 22. Advantages of using Software Engineering • Improved Quality. • Improved requirement Specification. • Improved cost and schedules estimates. • Better use of automated tools and techniques. • Less defects in final product. • Better maintenance of delivered software. • Well defined processes. • Improved productivity. • Improved reliability
- 24. Generic Product • For general purposes audience. • COTS – Commercial Off-the-shelf software. • Tough in designing and marketing • Imagination about the end-user is required. • Needs market survey and general customer demand analysis. • Risk is more • Examples : Word processors, Drawing packages, Project Management Tools, etc.
- 25. Customized Product • Also known as bespoke product. • Developed for specific organization/Customer. • Includes customer’s preferences & expectations. • Designed stage by stage . • Expensive. • Examples : Air traffic control systems, Core banking solutions
- 26. Software Attributes • Maintainability • Dependability • Efficiency • Usability
- 27. Contd… • Maintainability • Debug • Modify • Flexible • Testability • Portability • Reusability • Inter-Operability
- 28. Contd… • Dependability • Correctness • Reliability • Integrity • Security • Safety
- 29. Contd… • Efficiency • Memory Requirements • Processing time • Memory Utilization
- 30. Contd… • Usability • Training • User Familiarity • Consistency • User Guidance • Example : Scientific Calculator
- 31. Software Engineering Challenges • The Legacy Challenge • The Heterogeneity Challenge • The Delivery Challenge • The Trust Challenge
- 32. THANK YOU