CSCI-6961/ECSE-6780:
Software Engineering II
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Class: Mondays and Thursdays 4-5:20 pm, Carnegie 201
Instructor: Ana Milanova
Email: milanova@cs.rpi.edu
Office: Lally Hall 314
Phone: 518-276-6887
Office hours: Wednesdays 12-2pm, or by appointment
• Web: www.cs.rpi.edu/~milanova/csci6961/
• Syllabus: www.cs.rpi.edu/~milanova/csci6961/syllabus.html
What is Software Engineering II?
• Catalog: Current techniques in software
engineering with topics selected from
economics, reusability, reliable software,
program analysis, reverse engineering,
CASE tools, automatic code generation, and
project management techniques.
• Our focus: Program analysis and its
applications to software engineering,
especially towards techniques and tools for
improving software quality and reliability
Program Analysis
• Program analysis is a technique that reasons
about the run-time behavior of the program
– Static program analysis – reasoning is done
statically, before program execution
– Dynamic program analysis – reasoning is done
dynamically, during program execution
• We will focus on static program analysis
– Traditional application – compiler optimization
– New application – software engineering tools,
especially tools for improving software quality
and reliability
Software Quality and Reliability
• Development
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Requirements Analysis
Domain Analysis
Design
Implementation
Only about 5 to 10%
of cost!
– Testing/Validation
• Maintenance
– Enhancements
– Bug fixes
– Etc.
DEPLOYMENT/
RELEASE
90 to 95% of cost!
Economic Impact
• National Institute of Standards and Technology study
– On CNN.com – April 27th, 2003
– “Last year, a study commissioned by the National Institute
of Standards and Technology found that software errors
cost the U.S. economy $59.5 billion annually, or about 0.6
percent of the gross domestic product. More than half the
costs are borne by software users, the rest by developers
and vendors.”
Beyond Dollar Costs
• “Software Engineering: Report on a Conference
Sponsored by the NATO Science Committee,
Brussels, NATO Scientific Affairs Division,” 1968,
p. 121
– An error in an aircraft design program contributed to
several serious air crashes
• “Software and its Impact: A Quantitative
Assessment,” by B.W. Boehm, Datamation, 19(5),
48-59 (1973)
– Errors in medical software have caused deaths
Expectations
• Can’t we expect software to execute
correctly?
• Carefully made programs
– 5 faults/1000 LOC
– 5000 faults/1M LOC
• Windows XP has about 45M LOC
– 45 x 5000 = 225,000
Goals of the Course
• Learn about techniques for testing and validation
– Software testing --- systematic execution of the
software
• Learn/review fundamentals of testing
– Static program analysis --- track flow of control and
data without execution of the software
• Learn some theory of program analysis, learn about
applications of program analysis towards testing and validation
• Traditional static program analysis (data-flow analysis)
– Dynamic program analysis --- track flow of control and
data during execution of the software
Syllabus
• Course Material
– Static Program Analysis
– Fundamentals of Software Testing
– Dynamic Program Analysis
• Expected Work
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Project (50%)
Midterm (20%)
Homework (15%)
Presentation of a research paper (15%)
• Textbooks
Prerequisites
• SD&D/Software Engineering I
• Java
– Helpful to know, but other OO programming
will work too
• You will need a UNIX account on the CS
system for the class project
– Let me know if you don’t have one
Testing: Decades of Experience
Test Case
Test case Generation
(can be automated)
Executes the software.
Software
Under Test
Output
No
Good Coverage?
Yes
Validation
(can be automated)
Limitations of Testing
• Not enough!
• Kinds of bugs difficult to reveal with testing
– Resource leakage bugs
• Buffer overflows
• Memory leaks
– Concurrency related bugs
• Data races
• Atomicity violations
• Deadlocks
Static Program Analysis: Recently
Static
Analysis Tool
Specification --what bugs to look for?
(optional)
Software
Under Check
Examines the source code,
without execution.
Warnings
Examine warnings
and fix bugs
A Growing Area…
• Microsoft – investment in static analysis tools for
C/C++ with good results
• IBM – less, mostly in the J2EE area (some tools
are available through the Eclipse project).
• NASA, US Navy
• Successful companies with hundreds, even
thousands of clients
Our class, once again: techniques for
improving software quality and
reliability
• Static program analysis (data-flow analysis)
– Theory, applications and tools
• Fundamentals of software testing
– Review testing techniques, apply data-flow
analysis in testing
• Dynamic analysis
– Applications and tools.
Some Notable Software Bugs…
• A collection of notable software bugs
– Thanks to Atif Memon, University of Maryland
Mars Climate Orbiter
• Purpose: to relay signals from the Mars
Polar Lander once it reached the surface
• Disaster: smashed into the planet instead of
reaching a safe orbit
• Why: Software bug – failure to convert
English measures to metric values
• $165M
Shooting Down of Airbus 300
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1988
USS Vincennes shot down an Airbus 300
Mistook the Airbus 300 for an F-14
290 people dead
Why: Software bug --- cryptic and
misleading output displayed by the tracking
software
THERAC-25 Radiation Therapy
• THERAC-25, a computer controlled
radiation-therapy machine
• 1986: two cancer patients at the East Texas
Cancer Center in Tyler received fatal
radiation overdoses
• Why: Software bug --- a race condition (i.e.,
miscoordination between concurrent tasks)
London Ambulance Service
• London Ambulance Service Computer
Aided Dispatch (LASCAD)
• Purpose: automate many of the humanintensive processes of manual dispatch
associated with ambulance service
– Functions: Call tracking
• Failure of the London Ambulance Service
on 26 and 27 November 1992
“Nice of You to Turn Up”
• Load increased
• Emergencies accumulated
• System made incorrect allocations
– More than one ambulance being sent to the same incident
– The closest vehicle was not chosen for the emergency
• At 23:00 on November 28 the LAS eventually went
to a back-up procedure after at least 20 patients die
More…
• “The development of software for ballistic-missile
defense,” by H. Lin, Scientific American, vol. 253,
no. 6 (Dec. 1995), p. 48
– An Air New Zealand airliner crashed into an Antarctic
mountain
– North American Aerospace Defense Command reported
that the US was under missile attack; traced to faulty
computer software that generated incorrect signals
– Manned space capsule Gemini V missed its landing
point by 100 miles
More
• “Ghost in the Machine,” Time Magazine, Jan. 29,
1990. p. 58
– Dallas/Fort Worth air-traffic system began spitting out
gibberish in the Fall of 1989 and controllers had to
track planes on paper
• Software Reliability: Principles and
Practice, p. 25, by G. J. Myers
– Apollo 8 spacecraft erased part of the
computer’s memory
– Eighteen errors were detected during the 10day flight of Apollo 14
More…
– An error in a single FORTRAN statement
resulted in the loss of the first American probe
to Venus
– An Airbus 320 crashes at an air show
– A China Airlines Airbus A300 crashes on April
26, 1994 killing 264
– Ariane 5 satellite launcher malfunction was
caused by a faulty software exception routine
More…
• CNN.com
– A poorly programmed ground-based warning
system was partly responsible for the 1997
Korean Air crash in Guam that killed 228
people
– Faulty software in anti-lock brakes forced the
recall of 39,000 trucks and tractors and 6,000
school buses in 2000
• AND MANY MORE OF COURSE…