[SystemSafety] What do we know about software reliability?

[paul_e.bennett at topmail.co.uk]

On 9/16/2020 at 12:00 PM, "Les Chambers" <Les at chambers.com.au> wrote:
>
>Wow
>I’m impressed by the sustained passion in this debate. 
>It’s been raging for decades . I recall similar exchanges from 20 
>years ago when a project I was working on emptied out the V&V
>research group of a university department and put them to work
>on a SIL 2 rail project. The newly minted academics insisted you
>could put a figure on the reliability of software. They were met with
>peals of laughter by hardened players in the real world systems 
>development community. Outrageous fortune and years of exposure
>to size and complexity wore them down and they surrendered.
>
>For what it’s worth my view after 46 years in the business is that 
>reliability is an attribute of an organisation not a software or systems
>product. The best process  in the world is useless if the fleshware is
>not inclined to follow it. Trusted system is a misnomer. Customers
>buy from trusted organisations. An organisation is worthy of trust
>when it is populated by trustworthy people.
>
>Maybe it’s my age but everywhere I look I see Shakespeare. So when 
>your customer walks in the door think only this: He is here in double
>trust. First as I am his Kingsmen and his subject. Strong both against 
>the deed, then as his host. Who should against his murderer shut the
>door. Not bear the knife myself.
>
>Les

Where the hell is the 'LIKE' button when you need it?

Les, once again, succinctly stated the nub of the situation. There are a
different series of environments that form the gestation of a software
product. In regards software I dislike the term 'Reliabiiity' and prefer to
talk about 'Dependability'. Given that software always rests on the bed of
hardware, then can we discuss the 'Dependability'  of the logic of the
software without regard to all else except the logical states presented to
it in its cocoon of a perfect environment. Does that compartmentalise the
software product to be considered a component that can be inspected,
tested and even withstand attempts to destroy its functionality on purely
logical grounds. The resulting answer from the inspection and testing has
usually been rather binary in nature as it either does or does not meet the
stated intent.

Regards

Paul E. Bennett IEng MIET
Systems Engineer
Lunar Mission One Ambassador
-- 
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