1 / 8

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
Download Presentation

The problem of correctness

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  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/

More Related