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)!
Author Archives: Andrew
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.
Valuing Flexibility
I’ve just posted my review of “Real Options”, a book about financial market techniques to put a quantitative value on the benefits of flexibility. Unfortunately I was rather disappointed by the book – read my review to find out why.
However, reading the book has prompted me to do some more research in this field. I’m currently looking at whether combining the core valuation equation with probability decision trees might be useful. I’ll post more when I have some results.
Review: Real Options
Managing Strategic Investment in an Uncertain World, By Martha Amram, Nalin Kulatilaka
A rather disappointing book for the general reader
I was rather disappointed by this book.
I was hoping for something which could help explain to business managers why processes such as IT delivery are uncertain, and the value of delivering flexible solutions. The initial part of the book makes a lot of strong qualitative statements of exactly the right sort:
Review: Why Do Buses Come in Threes?
The Hidden Mathematics of Everyday Life, By Rob Eastaway and Jeremy Wyndham
An excellent reminder about why maths is fun
The two messages of this book are that mathematics is important to everyday life, and that it’s fun. Like the earlier books of Martin Gardener, this book aims to make mathematics relevant and accessible, but with a British rather than American slant.
Have you ever wondered why flowers often have five petals, how bookies’ odds work, how you always end up in the slowest queue, or, indeed, why buses come in threes? If so, then this is the book for you.
In the course of a humorous, chatty discourse on the mysteries of life the authors introduce a number of branches of mathematics, including probability, topology, statistics and queuing theory, to name just a few.
Why Do Buses Come in Threes?
I’ve just posted my reviews of two excellent books by Rob Eastaway and Jeremy Wyndham. “Why Do Buses Come In Threes?” and “How Long is a Piece of String?”
The messages of these books are that mathematics is important to everyday life, and that it’s fun. Have you ever wondered why flowers often have five petals, how bookies’ odds work, how you always end up in the slowest queue, or, indeed, why buses come in threes? If so, then this is the book for you.
Whether as an introduction if you’ve never enjoyed maths before, or a reminder if you have, I thoroughly recommend both books.
Review: How Long Is A Piece of String?
More Hidden Mathematics of Everyday Life, By Rob Eastaway and Jeremy Wyndham
Another excellent introduction to the fun of mathematics
This is a follow-up to the earlier, excellent, “Why Do Buses Come In Threes?”. While the earlier book focused on those annoying little mysteries of life, this asks a set of different questions, many related to tough decisions such as how conmen get rich, or “should I phone a friend?”
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.