I’ve just posted my review of this wonderfull book, by one of the world’s greatest leaders. The book is exciting, inspiring and, most of all, fun. I urge you to read it (and my review)!
Category Archives: Thoughts on the World
Review – My Early Life
The Laws of Identity
Microsoft have just published an excellent paper by Kim Cameron discussing the characteristics of an “identity metasystem” which must evolve if we are to have proper trust in the Internet and interactions which take place through it.
The paper is also available from the Identity Blog.
The paper’s thrust is that we need to develop a unifying set of identity-related technologies, but that these must observe certain key “laws”, and must accomodate varying technologies and requirements, much as unifying APIs provide access to a variety of hardware technologies.
I started thinking about the most common form of digital identify at the moment, the email address. It can be used in accordance with many of the laws. I can (usually) control when I release it. I can have different identities in different contexts, and choose which one to disclose. The identity is verifiable (to a limited extent) – someone can send me mail to check my address is valid. A variety of service providers and technologies are supported.
The big problem with email, of course, is that I can’t usually verify that email is from the claimed sender. For example, my spam whitelist admits email apparently from microsoft.com, but some of these emails are offers of dodgy mortgages and promises of increased manhood, obviusly not from the claimed source!
As a result, I wonder whether there is a missing “law of identity”. I need to be able to verify a claimed identity by methods I trust. I’d express the law something like “A party must be able to validate any identity claim, particularly its ownership, by reference (directly or indirectly) to resources he or she trusts.” This is implied in the current laws, but might be important enough to promote to a law in its own right.
Growing a Language
I’ve just read a wonderful paper by Guy L Steele, “Growing a Language“. He argues strongly that programming languages must be “small”, but able to grow. Such a language will have a relatively simple structure, syntactic rules, and a small core vocabulary. However it must also be able to “grow”, integrating new data types and functions, in the form of user code accessed in exactly the same way as core functions.
Steele’s argument is highlighted by the paper’s unique style – he uses a small but growing language himself. He writes using only words of one syllable, gradually adding other words he has defined in these terms.
The paper works at many levels. As well as the fascinating intellectual exercise in style, it makes a strong case for:
- simple but extensible programming languages,
- improving the extensibility of Java, rather than its core vocabulary,
- an agile community process for developing languages, rather than up-front design of great monoliths,
- the communication power of simple language and words.
Steele exhorts us to think about extensibility mechanisms – if we get these right then the core functionality can always grow. And by example, he encourages us to use simple, direct language and benefit from its discipline. On both accounts I agree wholeheartedly.
Enterprise Integration Patterns
Integration, like other design activities, can benefit from sharing ideas and proven strategies in the form of patterns. An excellent starting point is Gregor Hohpe and Bobby Woolf’s Enterprise Integration Patterns website and book.
In my recent work I’ve discovered a few patterns of my own, and I’ve started a page to document them.
First up is entitled “Change Indicator” . You may have a legacy system with an EAI adaptor, or a similar source of messages, which reports on the current state of key business objects. The messages will typically tell you when something has changed, but not necessarily what has changed, but the latter may be important to downstream systems. This pattern shows how to use EAI elements to add this information in a way which is totally transparent to the legacy system and existing users of the EAI scheme.
I Told You So
In Extensibility Points, Gregor Hohpe describes architecture as a guessing game, trying to understand future changes to a business, and designing a system to cater for those changes. He’s written a good article on types of extensibility and where they can be applied.
But Gergor’s article doesn’t really touch on understanding the dynamics of business change, and how these should dictate the form of architectural extensibility. Neither does he discuss the problem of being an architect who understands what flexibility is required, but being unable to get either the customers, or the suppliers, to agree. I seem to spend a lot of my time saying “I told you so” when a problem I predicted occurs – this is frustrating, even if I’m being proven right.
If you want to understand more about the dynamics of change, you might look at my previous postings on the subject:
Web Service Challenges
In a recent article, Gregor Hohpe asks “Is SOA Like Drunk Driving?” In our attempts to address the shortcomings of component-based development have we “swung too far” and introduced new problems?
One recent experience suggests to me that we may well be at risk of this. Read about my first experience of Web Service development and judge for yourself: have we thrown the baby out with the bath-water?
Blogging: What It Is and How It Works
Another good article published in the Microsoft Architecture Journal: If you don’t fully understand what a Weblog (or “Blog”) is, how it works, or what it may mean to you and your business, then this is for you.
The first part of “DasBlog: Notes from Building a Distributed .NET Collaboration System” is an accessible review of the phenomenon of blogging, and its implications for collaboration and knowledge management. Blogs cross several traditional boundaries: diaries, content management, collaboration, and news publishing. As a result both authors and readers are changing the way they get news and opinion from the web, and the new patterns are beginning to be reflected in corporate and project communications.
The second part of the article discusses some of the underlying technologies, like RSS, and how they can lead to increasingly rich linkage between the work of many authors.
Finally, the third section discusses the challenges of building a full-function open-source blogging engine using .NET technology. It’s very interesting, but gets quite technical. However you don’t have to follow, or even read, this to get benefit from the excellent first part.
Enterprise Architecture Design and the Integrated Architecture Framework
I’ve recently been catching up on the Microsoft Architecture Journal. This is an occasional MS publication, which can be downloaded from the
.NET Architecture Center. It’s got a lot of good articles, with a software architecture and process focus.
Of particular interest, there’s an article in the first edition by Cap Gemini on “Enterprise Architecture Design and the Integrated Architecture Framework”. Obviously every consultancy has their own architecture framework, and they all share some features, but what makes this one a bit different is the strong focus on the contextual (business context), conceptual (vision) and logical (solution independent capability) aspects, with technical details relegated to a bottom physical layer. It also has one of the best discussions I’ve seen on the relationship and differences between enterprise and project architectures.
Blogger Me!
My blog is now fully live. My Thoughts on the World, and the articles in
AgileArchitect.org, are now available via an RSS feed.
For the technically inclined, I’ve built my blog using a combination of VB.NET, Active Server Pages, and a bit of XSLT. This allows me to develop my site using FrontPage and IIS, and run it under Apache. If anyone’s interested I’ll write a technical note on it.
Business Flexibility
Inspired by an article on Richard Veryard’s SOAPBox Blog, this piece considers the business equivalents of expansion capabilities like the spare slots in a desktop PC.
A Fast Diff Algorithm
This recent posting to The Code Project is an implementation of a Diff
algorithm in VB.NET, with various techniques to improve performance, while
keeping the code simple.
Architects – Masters of Order and Unorder?
Do you work in an ordered environment, where things follow rules in a nice, predictable way? Or does your environment exhibit “unorder”, characteristics of complexity or chaotic behaviour. If the latter, you need to read this paper to understand how your domain may differ from others, and appropriate techniques to use as an architect, analyst or designer.

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