cnotes1 - 16.355 Software Engineering Concepts Prof. Nancy...

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16.355 Software Engineering Concepts Prof. Nancy Leveson Fall 2005
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Outline Is There a Problem? Why is Software Engineering Hard? Syllabus and Class Description Copyright c Nancy Leveson, Sept. 2000
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Is there a problem? Examples: AAS (FAA Advanced Automation System) FBI CIC IRS Modernization Program C−17 Ariane 5 Head of AF Systems Command: ‘‘Software is the achilles heel of weapons development" 7 out of every 10 major weapons development programs are encountering software problems and the rate is increasing. Copyright c Nancy Leveson, Sept. 1999
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Some "Data" (Myths?) Risks of cancellation or major delays rise rapidly as overall application size increases (Capers Jones): Failure or cancellation rate of large software systems is over 20% (Capers Jones) 25 % for those over 100,000 LOC 50% for systems exceeding half million LOC cancelled before completion 65% of large systems (over 1,000,000 LOC) are the most risky business undertakings in the modern world (Capers Jones) 5000 function points (~500,000 LOC) is one of Development of large applications in excess of Nancy Leveson, Sept. 1999 Copyright c
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More "Data" (Myths?) After surveying 8,000 IT projects, Standish Group reported about 30% of all projects were cancelled. Average cancelled project in U.S. is about a year behind schedule and has consumed 200% of expected budget (Capers Jones). Work on cancelled projects comprises about 15% of total U.S. software efforts, amounting to as much much as $14 billion in 1993 dollars (Capers Jones). c Copyright Nancy Leveson, Sept. 1999
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And Yet More Of completed projects, 2/3 experience schedule delays and cost overruns (Capers Jones) [bad estimates?] 2/3 of completed projects experience low reliability and quality problems in first year of deployment (Jones). Software errors in fielded systems typically range from 0.5 to 3.0 occurrences per 1000 lines of code Bell Labs survey). Civilian software: at least 100 English words produced for every source code statement. Military: about 400 words (Capers Jones) c Copyright Nancy Leveson, Sept. 1999
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software was never finished or used? What were some of the problems?
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cnotes1 - 16.355 Software Engineering Concepts Prof. Nancy...

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