[SystemSafety] Component Reliability and System Safety

[David Crocker]

Sorry, spelling autocorrect changed my attempt at entering "asserting" to "assisting".

On 14 September 2018 20:40:16 BST, David Crocker <dcrocker at eschertech.com> wrote:
>>> 
>Those people could **just** use static analysis tools, and get the same
>benefit. 
><<
>
>You are assisting that static analysis tools that don't enforce the
>MISRA guidelines provide as much safety as those that do. What are your
>grounds for that assertion? The MISRA guidelines have been produced and
>by a group of people from different backgrounds with experience of
>critical software written in C, and input from a much larger group, and
>gone though revisions. I doubt that any single vendor of a static
>analysis tool has the same breadth of experience. Of course there is a
>of of overlap, and there are some MISRA rules that I find questionable;
>but I'd rather use a published set of rules that have undergone
>scrutiny than an unpublished or poorly-documented set of rules that
>perhaps just one individual working for a tool vendor thought were good
>and easy to implement.
>
>>>
>Your answer doesn't address the system safety part of my question at
>all, afaict...
><<
>
>System safety requires at the very least a good set of requirements, an
>assembly of components that will meet those requirements if the
>components behave correctly, and components that behave correctly for
>all inputs they receive. MISRA helps with the last of those.
>
>On 14 September 2018 14:52:30 BST, Paul Sherwood
><paul.sherwood at codethink.co.uk> wrote:
>>On 2018-09-14 08:03, Peter Bernard Ladkin wrote:
>><snip>
>>>>> [Paul Sherwood, I think] Why is MISRA C still considered relevant
>>to 
>>>>> system safety in 2018?
>>> 
>>> (Banal question? Banal answer!)
>>
>>I'm sorry you consider my question banal. I mentioned your comment to
>>an 
>>eminent friend (who has had to deal with the human fallout from
>>multiple 
>>accidents) and he said "There are no banal questions about safety. 
>>Anyone asking questions and interested in safety is to be applauded."
>>
>>Are list members here normally prone to sniping at each other? Is the 
>>community OK with that? I confess I can be quite harsh myself, but I
>>try 
>>to give new contributors the benefit of the doubt.
>>
>>> Because many people use C for
>>> programming small embedded systems and
>>> adhering to MISRA C coding guidelines enables the use of static
>>> analysis tools which go some way
>>> (but not all the way) to showing that the code does what you have
>>said
>>> you want it to do.
>>
>>Those people could **just** use static analysis tools, and get the
>same
>>
>>benefit. Your answer doesn't address the system safety part of my 
>>question at all, afaict, but I found other answers more helpful in
>that
>>
>>regard.
>>
>>br
>>Paul
>>
>>_______________________________________________
>>The System Safety Mailing List
>>systemsafety at TechFak.Uni-Bielefeld.DE
>
>-- 
>Sent from my Android device with K-9 Mail. Please excuse my brevity.

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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