[SystemSafety] What do we know about software reliability?

[Derek M Jones]

John,

> In my experience, if Software Reliability is mentioned at a conference, at least one member of the audience will laugh, and if it is mentioned in a work discussion, at least one member of the group will get angry.

I am guessing they laugh because so much nonsense is spoken,
and they get angry because there is always somebody who says
more should be invested to increase reliability.

I am all for investing to increase reliability, just don't
ask me how to quantify unit increase in reliability per unit of
investment.  At least until somebody figures out how to do this.

> Interestingly, some of the same people who say it is impossible to quantify software failure rates will set numerical requirements for Software Availability - if you get one of those, ask the Customer how (s)he wants you to demonstrate satisfaction of the requirement.

Fuzzing appears to be a practical technique for gathering the data needed to
estimate likely number of mistakes that will cause a system crash.  Practical
in that a few months of cpu time is quite cheap these days.

Techniques for non-crash failures are being researched (so don't hold your breath).

> 
> John
> From: systemsafety <systemsafety-bounces at lists.techfak.uni-bielefeld.de> On Behalf Of Derek M Jones
> Sent: 14 September 2020 12:54
> To: systemsafety at lists.techfak.uni-bielefeld.de
> Subject: [SystemSafety] What do we know about software reliability?
> 
> All,
> 
> What do we know about software reliability?
> 
> The answer appears to be, not a lot:
> http://shape-of-code.coding-guidelines.com/2020/09/13/learning-useful-stuff-from-the-reliability-chapter-of-my-book/<http://shape-of-code.coding-guidelines.com/2020/09/13/learning-useful-stuff-from-the-reliability-chapter-of-my-book>
> 
> --
> Derek M. Jones Evidence-based software engineering
> tel: +44 (0)1252 520667 blog:shape-of-code.coding-guidelines.com
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-- 
Derek M. Jones           Evidence-based software engineering
tel: +44 (0)1252 520667  blog:shape-of-code.coding-guidelines.com