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As another example, I want to show you the architecture of the

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iRods system. This is a data grid system that was built by

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a biologist. And it's a system for storing and accessing big

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data. So what I'm going to do, I'm going to do the same thing

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that I did for the Linux system. I'm going to show you

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here, on the left hand side, this clean prescriptive architecture for the

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iRODS system. And I'm going to show you here on the right the

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actual architecture of the system. The

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descriptive architecture of iRODS. So here,

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even if we don't go in and look at the details, you

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can see very easily that the system is badly drifted and eroded

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with respect to the way it was supposed to be. Continuing

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with the examples. What I want to show you now is the

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view of the complete architecture of HADOOP. As many of you probably

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already know, HADOOP is an open source software framework for storage and

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large scale processing of data sets. It's very broadly used. And here

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is a picture of the architecture, and I hope you can see it

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because the architecture is so complex and so broad and so

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intertwined, and in order to be able to represent it here

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in one page, I had to zoom out quite a bit.

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But also in this case, you don't really have to look

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at details. The important point here is that in this software architecture

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61 out of the 67 components in the system have circular

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dependencies. Which means that they depend on each other in a

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circular way and this is normally not a good thing and also

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in this case a few developers when shown the diagram had no

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idea that the structure of the system was so complex and messy.