John McDermid (John.McDermid(at)cs.york.ac.uk)
Fri, 15 Dec 2000 18:10:33 -0000
One doesn't know anything, but the first possibility you mention occurred to me as well. John ----- Original Message ----- From: "A.R. Lawrence" <arl(at)bflat.demon.co.uk> To: <safety-critical(at)cs.york.ac.uk> Sent: Thursday, December 14, 2000 9:00 PM Subject: Re: "Software fault forces Ford recall" > I always thought that programming was one of the final steps in the design > process - apparently this is not the case for the Ford Explorer. > > My best guess at the causes of the problem are: > > 1. the brake pedal should disconnect the auto throttle (but the TV programme > showed that it doesn't) - I wonder if there is an (unecessary) bit of logic > which does not reset the autothrottle if the autothrottle has not been > selected (the TV programme showed the autothrottle cutting to full power > when electrical inteference existed under the bonnet) - perhaps the way to > make the brake pedal 'disconnect' the autothrottle is to press the engage > button on the steering wheel when the runaway condition occurs so that the > brake pedal can then disconnect it. I accept that it is difficult to be > able to make this kind of analysis when you are careering down a city road > out of control. > > 2. The penultimate paragraph of the Register note was interesting - it > refers to a 100mph upper limit - does the fault condition somehow try to use > this is a *minimum* speed? > > Does anyone know if these hypotheses are correct? > > Perhaps if Ford make the programming phase part of the design phase and some > attempt at postulated fault analysis and static code analysis is performed, > people may not be killed because their vehicles contain critical software > which is erroneous because of 'the way it was programmed' > > Arthur Lawrence > > > From: Jonathan Moffett <jdm(at)cs.york.ac.uk> > > Reply-To: safety-critical(at)cs.york.ac.uk > > Date: Wed, 13 Dec 2000 18:55:49 +0000 > > To: safety-critical(at)cs.york.ac.uk > > Cc: philippa(at)cs.york.ac.uk > > Subject: "Software fault forces Ford recall" > > > > Thanks to Philippa Conmy for this information, headed ""Software fault > > forces Ford recall" at http://www.theregister.co.uk/content/4/15445.html > > > > Jonathan Moffett > > > >