Tag Archives: cloud

Risk-driven approaches to dependability

I’ve been reading a lot about cloud security today as, perhaps rather hastily, I offered to lead a discussion on my gut feeling that there is really nothing new in cloud security.  When you read articles on this topic, what strikes you is that they focus on security technicalities rather than the security risks that businesses face every day. I’ve written about the specific issues around cloud security in my Cloudscape blog.

But this brings me to a more general point that I make in my book but which perhaps needs emphasising again. When you have a limited amount of resources to spend on achieving dependability, start by identifying the risks and threats to system dependability. Focus on those risks which have a (relatively) high probability of occurring and the risks that have serious consequences.  Think about how your software and your testing process should cope with these problems – if you can avoid the biggies, then you will achieve dependability.

This is one of the problems that I have with automated testing. There is an emphasis on taking bottom-up approach, where you write unit tests for a component, with no idea of whether these include practical usage scenarios. There is a tendency to think that software that passes all the automated tests is necessarily dependable – but if you haven’t covered all the risks, then you could be in for a surprise.

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Filed under dependability, software engineering