Tweedle Dum and Dee (Image source: Wikipedia Commons)

Revisiting the Knight, Leveson experiments

In the through the looking glass world of high integrity systems, the use of N-version programming is often touted as a means to achieve extremely lower failure rates without extensive V&V, due to the postulated independence of failure in independently developed software. Unfortunately this is hockum, as Knight and Leveson amply demonstrated with their N version experiments, but there may actually be advantages to N versioning, although not quite what the proponents of it originally expected.

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For those of you in northern climes, here’s some tips on safer summer reading, and for once I have nothing to add. :)

Yours truly

I’ve just finished reading an interesting post by Andrew Rae on the missing aspects of engineering education (Mind the Feynman gap) which parallels my more specific concerns, and possibly unkinder comments, about the lack of professionalism in the software community.

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Hazard checklists

06/07/2014 — 1 Comment

As I had to throw together an example checklist for a course I’m running, here it is. I’ve also given a little bit of a commentary on the use, advantages and disadvantages of checklists as well. Enjoy. :)

System Safety Fundamentals Concept Cloud

There’s a very interesting site,  run by a couple of Australian lads, called Text is Beautiful that provides some free tools that allow you to visually represent the relationships within a text. No this isn’t the same as Wordle, these guys have gone beyond that to develop what they call a Concept cloud, colours in the Concept Cloud are indicative of distinct themes and themes themselves represent rough groupings of related concepts. What’s a concept? Well a concept is made up of several words, with each concept having it’s own unique thesaurus that is statistically derived from the text.

So without further ado I took the Fundamentals of System Safety course that I teach and dropped it in the hopper, the results as you might guess are above. Very neat to look at and it also gives an interesting insight into how the concepts that the course teaches interrelate. Enjoy. :)

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The DEF STAN 00-55 monster is back!!

That’s right, moves are afoot to reboot the cancelled UK MOD standard for software safety, DEF STAN 00-55. See the UK SCSC’s Event Diary for an opportunity to meet and greet the writers. They’ll have the standard up for an initial look on-line sometime in July as we well, so stay posted.

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Cleveland street train overrun (Image source: ATSB)

The final ATSB report, sloppy and flawed

The ATSB has released it’s final report into the Cleveland street overrun and it’s disappointing, at least when it comes to how and why a buffer stop that actually materially contributed to an overrun came to be installed at Cleveland street station. I wasn’t greatly impressed by their preliminary report and asked some questions of the ATSB at the time (their response was polite but not terribly forthcoming) so I decided to see what the final report was like before sitting in judgement.

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