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The problem of correctness

The problem of correctness. Consider the following program: Read(ch) WriteString(‘42’) is this correct?. The problem of correctness. A program is meaningless without a specification It is nearly useless without a formal specification.

bianca-campbell
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The problem of correctness

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  1. The problem of correctness • Consider the following program: • Read(ch) • WriteString(‘42’) • is this correct?

  2. The problem of correctness A program is meaningless without a specification It is nearly useless without a formal specification.

  3. Formal methods are essentially the mathematical foundations of software engineering • In comparison with many other engineering disciplines, SE is in its infancy

  4. Formal methods can Guarantee the software is bug free • Formal methods are about proofs • Formal methods are only useful for critical systems • Formal methods require mathematicians • Formal methods increase the cost of development • Formal methods are unacceptable to users • Formal methods are not used in real large scale systems

  5. Seven Myths of Formal Methods: 1. Formal methods can guarantee that software is perfect. Rather: they are very helpful at finding errors early on and can nearly eliminate some classes of error. 2. They are all about program proving. Rather: they work largely by making you think very hard about the system you propose to build. 3. They are useful only for safety-critical systems. Rather: they are useful for almost any application. 4. They require highly trained mathematicians. Rather: they are based on mathematical specifications, which are much easier to understand than programs. 5. They increase the cost of development. Rather: they can decrease the cost. 6. They are unacceptable to clients. Rather: they help clients understand what they are buying. 7. They are not used on real, large scale software. Rather: they are being used successfully on practical projects in industry. Quoted from: J. Anthony Hall, Seven myths of formal methods, IEEE Software, 7(5):11-19, September 1990.

  6. More.. 7 more myths: csdl.computer.org/dl/mags/so/1995/04/s4034.pdf • More papers/publications www.afm.sbu.ac.uk/pubs/ • B papers and publications www.afm.sbu.ac.uk/b/

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