Software Engineering

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Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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Why Software Engineering ?
Change in nature & complexity of software Concept of one “guru” is over We all want improvement

Ready for change
Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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The Evolving Role of Software
Software industry is in Crisis!
success 16%

failure 31%

over budget 53%
Source: The Standish Group International, Inc. (CHAOS research) Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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The Evolving Role of Software

This is the SORRY state of Software Engineering Today!
• Data on 28,000 projects completed in 2000

Completed Late, over budget, and/or with features missing – 49%

Successful – 28%

Cancelled – 23%

Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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The Evolving Role of Software

As per the IBM report, “31%of the project get cancelled before they are completed, 53% overrun their cost estimates by an average of 189% and for every 100 projects, there are 94 restarts”.

Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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The Evolving Role of Software

Hw cost Sw cost

Year 1960 1999 Relative Cost of Hardware and Software
Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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The Evolving Role of Software
• Unlike Hardware
– Moore’s law: processor speed/memory capacity doubles every two years

Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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The Evolving Role of Software
Managers and Technical Persons are asked:
Why does it take so long to get the program finished? Why are costs so high? Why can not we find all errors before release? Why do we have difficulty in measuring progress of software development?

Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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Factors Contributing to the Software Crisis
• Larger problems,

• Lack of adequate training in software engineering, • Increasing skill shortage,

• Low productivity improvements.

Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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Some Software failures
Ariane 5
It took the European Space Agency 10 years and $7 billion to produce Ariane 5, a giant rocket capable of hurling a pair of three-ton satellites into orbit with each launch and intended to give Europe overwhelming supremacy in the commercial space business. The rocket was destroyed after 39 seconds of its launch, at an altitude of two and a half miles along with its payload of four expensive and uninsured scientific satellites. Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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Some Software failures
When the guidance system’s own computer tried to convert one piece of data the sideways velocity of the rocket from a 64 bit format to a 16 bit format; the number was too big, and an overflow error resulted after 36.7 seconds. When the guidance system shutdown, it passed control to an identical, redundant unit, which was there to provide backup in case of just such a failure. Unfortunately, the second unit, which had failed in the identical manner a few milliseconds before.

Software Engineering (3rd ed.), By K.K Aggarwal & Yogesh Singh, Copyright © New Age International Publishers, 2007

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Some Software failures
Y2K problem:
It was simply the ignorance about the adequacy or otherwise of using only last two digits of the year. The 4-digit date format, like 1964,...
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