Hitchhiker's Guide to Software Architecture and Everything Else - by Michael Stal

Thursday, January 31, 2008

Learning from failure: Bangalore and Software Architecture

I am currently enjoying my time here in Bangalore (India) where I am giving some talks and trainings on Software Architecture. Especially, the hospitality here is marvellous. Bangalore is a very fast growing city with very nice people and a hot spot due to its IT companies and IT experts. On one hand, all the high tech industry is quite impressing. On the other hand, it is astonishing to see hightech centers in a lowtech infrastructure. Interesting, you might think, but how is this related to software architecture? When speaking to colleages here and to my driver (you cannot and should not manage to drive yourself as someone more used to the US or German car driving patterns :-), they told me a lot of interesting things related to Bangalore's infrastructure which I consider likewise applicable to software architecture. Don't be embarassed that I explicitly use Bangalore. It is a pars-pro-toto. Any other big metropoles would do also, but now that I am here ....

  • Bangalore's population significantly increased over the last years. Unfortunately, the infrastructures could not be increased accordingly. What formerly has been garden city, a small green place, has now become a big metropole. A good example is the traffic infrastructure. It has turned to a significant bottleneck (also known as nightmare) so that it might take you an hour even for small distances. What can we learn as software architects: We must plan for non-functional qualities such as scalability and prepare the system to increase when the load increases. Doing this as an afterthought can prove to be almost impossible. Of course, this is hard for a city.
  • As an implication of the insufficient traffic infrastructure, drivers of cars, motorbikes, bicycles, busses, trucks, rickshaws will just use any available gap of a traffic lane. Thus 3 lane streets will become 6 lane streets. There is almost no traffic control except for a few police men (and I am not sure how much control thy really have). The most important tool is the horn to tell other persons that you are here. What can we learn as software architects: governance is an important issue. Make sure that everyone abides to the rules. Overload situations in a system also make it nondeterministic as you can never anticipate how much time particular activities will require.
  • If you drive around in Bangalore, you will find no direction signs at all. Want to go somewhere? Better know the route or follow a trial-and-error approach until the end. What we can learn as software architects: usability and habitability should be considered important. Otherwise, users may have a very unpleasent time with your product.
  • The current airport is a former military airport and thus can provide only limited and sometimes slow service. Now, the local government is opening a new international airport to solve the problem. Unfortunately, there will be no fast train or highway connections from the airport to the city center. People from Electronics City (the Silicon Valley of India) suppose, it will take them 3 hours to reach the airport. What can we learn as software architects: If a service is very performant or offers otherwise high quality of service, this won't help you much once it takes a long time to send your request to the
    service or to receive a response. You always need to look on the system as a whole. And you always should remember the weakest link in the chain defines what quality you will obtain.
  • To improve the infrastructure several construction works are on the way. For example, there will be a new multi lane highway. However, this highway will end in a two lane highway. Guess what what happens on the junction of these highways? What
    can we learn as software architects: Also mind the connections. Local optimizations might help locally but can not solve problems that should be addressed globally. First think strategically and then tactically.
  • In the previous days there were some news about people who suffered severe illnesses from drinking the local drinking water. It turned out that some people didn't follow the regulations and just installed sewage pipelines near water pipelines.
    Imagine what will happen if erosion leads to lecks where both systems join? What can we learn as software architects? First of all, it is not sufficient to provide guidelines and throw them over the fence. An architect must also control that developers abide to the rules. Second, design erosion can lead to unwanted side effects. Instead of waiting for problems to occur, it is better to apply refactorings or even a complete reengineering. The latter is almost impossible for a real city infrastructure. Third, you need to keep in mind how infrastructures interact with each other. Fourth, you need to plan upfront for modifiability and later evolution to prevent such workarounds.

Take this example and think about ULS (Ultra Large-Scale Systems). The ULS proponents compare ULS with building cities instead of building houses where you also will also have to deal with human interaction and creating/maintaining/evolving large infrastructures. As soon as we are starting to deal with such ULS (systems of systems) we need to make sure such design erosion will not happen. There is a lot to learn from real life for cyber techies.


Post a Comment

<< Home