Metropolis

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Metropolis - Urban Design and SOA

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In the twentieth century, the two of the best writers on the nature of cities were Lewis Mumford and Jane Jacobs. Mumford thought a well-ordered city needed central planning and infrastructure (in other words, Top-Down), while Jacobs took a more anarchist position (Bottom-Up).

Microsoft guru Pat Helland has written an article exploring similarities between city design and service-oriented architecture.

Christopher Alexander wrote a book on Urban Design in 1987, which is overdue for recognition among software practitioners. His latest work The Nature of Order has just appeared.

Nikos Salingaros is a mathematician who has worked with Alexander for many years. There are many useful articles on his website.

There are some strong parallels between town planning and service-oriented architecture, which make it reasonable to translate ideas and experience from urban design into the SOA domain.

1. The distribution of design.
Detailed design decisions are taken within different organizations, each following its own agenda (e.g. commercial or political goals).

2. The constancy of change.
Elements of the whole are constantly being redesigned and reconfigured, and new elements are constantly being added. Structures must evolve in robust ways.

3. The need for progressive improvement.
Each design increment should not only make local improvements, but should have a positive effect on the whole.

4. The recursive nature of the architecture.
Similar design tasks must be carried out at different scales (levels of granularity).

Adaptability
In 19th century England, Manchester was highly adapted to the cotton industry, but failed to adapt to later waves of industrialization. Meanwhile, Birmingham was far more adaptable, and this enabled it to accommodate a series of industrial innovations.

source Jane Jacobs, cited by Salingaros

Complexity
A city contains a vast quantity of social and commercial interaction. A living city allows for many different levels of such interaction, and for meaningful clusters and subclusters to emerge, forming an abstract hierarchy.

Governance
City planning requires orchestration of developments large and small, balancing local initiative and autonomy against global coherence.

Business-Driven SOA (May 2004)

Business-Driven SOA continued (June 2004)

Newswire on Service-Based Design (David Sprott)

Helland on Metropolis

veryard projects > service orientation > metropolis > helland

In a piece called Metropolis, published in the Microsoft Architects Journal, Microsoft guru Pat Helland has written about the relationship between service-oriented networks and cities.

Helland’s article makes the following argument.

1 Progress requires standardization. (According to Helland, people didn’t even wash properly until they had standard clothing.)

2 Standardization is associated with commoditization.

3 Standardization requires concentration of power (and if this involves pathological distortions of socioeconomic relations, such as WalMart or dare we say it Microsoft, so be it).

4 Infrastructure requires central investment. (Since we may regard infrastructure as an act of local standardization, it follows that it must involve concentration of power.)

5 Central investment preserves the “sacred”.

I was however surprised that he does not mention the work of Christopher Alexander - especially his 1987 book A New Theory of Urban Design. Given the influence that Alexander's earlier books on structure and patterns have had on the software engineering community, it is amazing how few people in this community have read his later work.

The analogy between computer networks and cities has also been explored by the mathematician Nikos A. Salingaros. See especially his piece on the Information Architecture of Cities.
For more commentary on Helland's piece see the Newswire on Service-Based Design by my colleague David Sprott (CBDI Forum).
See also Peter Lindberg's blog.

veryard projects > service orientation > metropolis