Software Process Improvement

1
Software Process Improvement

• Current Problems
• Promising Approaches/Solutions
• Nature of Software Engineering
• Software Engineering Research
• Recent Developments and the Future

2
Software Chronic Crisis
W. Wayt Gibbs, Software Chronic Crisis,
Scientific American, September 1994

• Studies in the USA have shown
• For every 6 new large-scale software systems put
  into operation, 2 others are cancelled!
• The average software development project over
  shoots its schedule by half (and larger projects
  generally do worse).
• Around 75 of all large systems are operating
  failures i.e. do not function as intended or are
  not used at all. Source of USA figures
  Software Productivity Research

3
History

• Programming has been an established activity
  undergoing refinement for more than 50 years.
• Over 25 years ago, in Autumn 1968, the Software
  Crisis was acknowledged, and the establishment
  of Software Engineering was proposed as a means
  of solving the Software Crisis of 1968 where SE
  is the application of a systematic, disciplined,
  quantifiable approach to the development,
  operation and maintenance of software.

4
Current Situation

• However, today the vast majority of code is still
  hand crafted from programming languages by
  artisans using techniques they neither measure
  nor are able to repeat consistently.
• But academics have made some progress in formal
  methods and in instituting software engineering
  degrees.
• Industry has made some progress towards market
  structures and technology supporting reusable
  software parts.
• Even so, a research innovation typically requires
  18 years to become standard industrial practice.
• SEI finding

5
Current trends The decade ahead

• A combination of academic industry and government
  is needed to hoist software development to the
  level of an industrial age engineering discipline
  within the decade (2005)
• As we move into the Information Age, error-free
  software will become the expected norm.
• This will be especially true for embedded
  software in consumer products.
• The amount of s/w in consumer products is
  doubling every 2 years e.g. TV 500Kb,
  Shaver 2Kb
• Existing problems in attempts to develop
  error-free Real-Time s/w for defense applications
  do not give us confidence (Gilles Kahn of INRIA)

6
Large System Integration Problem

• Example 1987 CA Department of Motor Vehicles
  commissioned system to merge states driver and
  vehicle registration systems.
• Goal was one-stop renewal kiosks in 1993
• Costs exploded 6.5 times and delivery date
  receded to 1998
• Project cut after 7 years and 44.3 M dollars
  investment loss.

7
Large and growing systems...

• In general, software systems have seen an order
  of magnitude growth in size every decade (for
  some industries this has occurred every half
  decade). SEI finding
• Software disasters inevitable unless software
  development became engineering discipline with
  roots in science and mathematics.

8
Some Solutions

• Progress on Software Process, e.g. the SEIs
  Capability Maturity Model (CMM)
• 5 Level Model - 1 is Chaotic, 2 is Repeatable, 3
  is Defined, 4 is Managed and 5 is Optimising
• But 75 of companies are at Level 1 and 24 are
  at Levels 2 and 3.
• USA Space Shuttle software maintenance is at
  Level 5.

9
Mathematical Foundations and Formal Methods

• Progress on error-free software is slow.
• Plan in mid90s to beta-test new version of
  Windows by 20,000 volunteer. Microsoft Chief
  Architect C Simonyi
• This is expensive, inefficient and usually
  impractical.
• View of Martyn Thomas founder of Praxis is that
  we should rely on mathematical analysis of formal
  specifications to predict how software will
  behave.
• Applicable to either on most critical parts or
  whole systems.

10
Clean Room Approach and Improved Testing

• Clean Room Application of rigorous engineering
  techniques from electronic engineering
• Coupled with new approaches to testing
  emphasizing probabilities of execution paths.
  Putting testing on a more scientific basis.

11
Progress on Software Reuse

• There is some work on component based
  development, reusable parts and standardisation
  to support reuse
• But more research is needed before this becomes
  widespread industrial practice.

12
No Single Solution

• A combination of Approaches is needed - there is
  no silver bullet!
• In addition, Software Engineering needs a better
  empirical basis - we need more experiments!
• E.g. Software productivity measurement problems
• No reliable data
• No uniform measures
• No quality considerations (1000 lines of
  spaghetti or lasagna.

13
Summary

• Future Topics
• Process Models and Improvement
• Formal Methods
• Clean Room
• Empirical basis of Software Engineering