[SystemSafety] Operational logging for medical devices

[Olwen Morgan]

On 26/11/2018 15:31, Peter Bernard Ladkin wrote:
> On 2018-11-26 14:14 , Olwen Morgan wrote:
>> <snip>
> I suggest that operational logging is essential for any software for 
> which reliability or safety is key. Furthermore, the design of such 
> logging is not trivial if you want it to be trustworthy, although the 
> implementation could well be straightforward when you have the design 
> right. Or not.....

<snip>

When working on micro-controller applications, I've often suggested 
putting logging functions into the code to log sensor readings on 
acquisition and actuator settings on disposition. So far, I've not seen 
any form of logging that is simpler than that, though whether that is 
appropriate is highly application-dependent. Things get complicated when 
you have to log to volatile memory for speed and can only catch up later 
to write a block of readings to nonvolatile storage. Often that 
betokens, IMO, poor choice of controller chip. You get firms being 
penny-wise and pound-foolish - sometimes working to a target hardware 
cost that has been set purely by accountants.


Olwen