Notes on Software Quality

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CS 425 / 625 Software Engineering

• Notes on Software Quality

Sergiu Dascalu Muhanna Muhanna
University of Nevada, Reno Department of Computer
Science and Engineering
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Overview

• Software quality
• Software quality assurance (SQA)
• SQA challenges
• Current trends
• Research directions
• Main references

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1 Software Quality

• It is rather hard to define what exactly software
  quality is
• In general, it is acknowledged that software that
  satisfies its requirements has good quality
• Several quality model exists, one of them
  stresses Sommerville, 2004
• Maintenability
• Efficiency
• Dependability
• Usability

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1 Software Quality

• In practical terms, software quality is important
  because lack of quality translates to user
  frustration, financial losses, material damages,
  human injuries and even deaths
• Known disasters due to software failures include
  Glass 1998 Endres and Rombach 2003
• The baggage handling system for the Denver
  airport
• The welfare administration system for the state
  of Florida
• The air-traffic control system for the FAA
• Other examples are listed by Tywebb Ltd 2007-8

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1 Software Quality

• Some other illustrations YouTube 2008
• Operating system demo crash
• TV show software error
• Arctic Tortoise field test problems
• Autonomous crash in DARPA Urban Challenge
• Unmanned plane clash
• To do justice to software developers, their job
  is a very demanding one, something captured in
  the ad if programmers had to make a plane
  YouTube 2008

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2 Software Quality Assurance

• Software Quality Assurance (SQA) is defined by
  the IEEE Standard 610.12 1990 as a planned and
  systematic pattern of all actions necessary to
  provide adequate confidence that an item or
  product conforms with established technical
  requirements
• The SQA Handbook defines SQA as the set of
  systematic activities providing evidence of the
  ability of the software process to produce a
  software product that is fit to use Schulmeyer
  and McManus 1998

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2 Software Quality Assurance

• SQA is distinct from software quality control
  which consists primarily of inspecting
  requirements documents and software testing. SQA
  covers the entire software development process,
  which includes software specification, design,
  implementation, integration, testing, source code
  control, code reviews, version control, and
  release management Wikipedia 2008.

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2 Software Quality Assurance

• Also according to Wikipedia 2008 SQA focuses on
  the control of processes, rather than on the
  control of products.
• Current software processes have evolved for
  waterfall to the Unified Process (UP), with many
  variations in between
• The waterfall model Sommerville 2006

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2 Software Quality Assurance

• The Unified Process Arlow and Neustadt 2005

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3 SQA Challenges

• SQA challenges include Voas 2003, Pressman 2004,
  McConnell 1993
• Dealing with increasing complexity of software
  processes and products
• Defining improved quality models
• Integrating better with development processes
• Increasing the evidence that standards that
  promote higher quality software bring indeed
  significant benefits

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3 SQA Challenges

• SQA challenges include Voas 2003, Pressman 2004,
  McConnell 1993 continued
• Finding out ways to compose standards
• Improving QA models and processes
• Increasing software quality-centric adaptability
• Increasing SQA independence from software
  development
• Dealing with the perception that QA is less
  glamorous than development

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4 Current Trends

• Current SQA trends relate to focusing on the
  following Lyu 2007 SEI 2008 McConnell 1993
  Sommerville 2006
• Metrics and measurements
• Methods and tools
• Testing effectiveness and code coverage
• Inspections, reviews, and walkthroughs
• Software architectures
• Management and certification

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5 Research Directions

• Research directions in SQA, besides facing
  challenges mentioned previously, include Lyu
  2007 Bertolino 2007, Mnkandla 2006, Parsons
  2003
• QA for COTS-based software
• QA for agile development processes
• QA for open-source software
• Metrics for software reliability prediction
• 100 automatic testing
• Personal and Team software processes

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Main References

• Endres, A and Rombach, D., A Handbook of Software
  and Systems Engineering, Addison-Wesley Pearson,
  2003
• Ghezzi, C., Jazayeri, M, and Mandrioli, D.,
  Fundamentals of Software Engineering, 2nd
  edition, Prentice Hall, 2002.
• McConnell, S., Code Complete A Practical
  Handbook of Software Construction, Microsoft
  Press, 1993.
• Pressman, R., Software Engineering A
  Practitioners Approach, 6th edition, Prentice
  Hall, 2006.
• Software Engineering Institute at Carnegie Melon
  University, last accessed March 8, 2008 at
  www.sei.cmu.edu
• Sommerville, I., Software Engineering, 8th
  edition, Addison-Wesley, 2006
• Voas, J., Assuring Software Quality Assurance,
  IEEE Software, May?June 2003, pp. 48-49
• Wikipedia.com, last accessed March 9, 2008 at
  www.wikipedia.com
• YouTube.com, last accessed March 9, 2008 at
  www.youtube.com