Simple Architectures for Complex Enterprises

by Roger Sessions

Dismantle the overwhelming complexity in your IT projects with strategies and real-world examples from a leading expert on enterprise architecture. This guide describes best practices for creating an... This description may be from another edition of this product.

• Format: Paperback
• Language: English
• ISBN: 0735625786
• ISBN13: 9780735625785
• Release Date: May 2008
• Publisher: Microsoft Press
• Length: 181 Pages
• Weight: 0.96 lbs.
• Dimensions: 0.6" x 7.3" x 8.9"

Customer Reviews

Easy read

Sessions correctly identifies the real enemy of IT; complexity. Exploring the facets of simplicity and its applicability to Enterprise Architecture makes this book well worth reading. If the author repeats himself, it's only to bash this important concept into our thick skulls. Let we never forget! I wish more books explored this topic.

Yes - to simplicity.

I enjoy Roger Sessions and read his newsletters and past books. This book is on par with other Roger Sessions writtings. Roger's work is very well thought out as well s logical. What seems to be missing, for me at least, is the clear cut solution. The computer solutions world is complex by default. Most computer professionals are so wrapped up in current implementations, politics, issues, self-centered solutions, etc., that the clear-cut path foward is impossible to find. It seems like the Roger Session reader is a lone wolf crying in the forest. The organization around them is not interested. Yes, the book finishes with the path forward, but, for me anyway, does not give the arguments needed for change. There needs to be the simplistic points to wake up the ITD departments. That is what I see missing in Roger's books. BUT, I AGREE WITH HIS REASONING AND SOLUTIONS, COMPLETELY! Now on to this book. The first part of the introduction is probably the key to the rest of the book and best addresses the general complaint listed above. Everyone, in every IT department, should read this section. The first chapter is an overview of system architecure in general. This chapter alone is worth the price of the book, to me at least. Too many organisations focus on a very small part of architecture and that small part as the enterprise solution. This chapter encapsulates the what, why, and failure of enterprise architecure methodology. The next couple of chapters discuss complexity and proofs of complexity. After that, he discusses partitioning, why partitioning is benefical, and explains his partitioning process. I appreciate Roger Sessions thought process and encourage all computer professionals to read.

Not 100% applicable

The general approach to any grand IT problem is to break it down to smaller manageable pieces. Pieces that our pathetically puny brains can contain and work on at a time. Any decent software developer would have known that. And yet, we still continue to produce massive, monstrous, monolithic code that is a complete beast to interpret, comprehend, and modify. In other words, a mesh of _unmanageable_complexity_. There is without a doubt such technical misshaping contribute significantly to the schedule and budget overrun in way too many large projects, and ultimate failure. But what am I talking about? This book is not about software applications. As an enterprise architect, Author Roger Sessions takes us up several floors to show us where he believes all these complexity evil germinates - the failure to control the complexity of IT inter-system communication across the organisation. He writes this volume to explain the problem of complexity can be illustrated via mathematical models, and purports that the application these mathematical exercises and further concepts of organisation will help divide the enterprise into simple easy pieces. _That_ is a rather mighty claim. Is this for real? Roger Sessions starts out strong. He begins mentioning existing methodologies and frameworks used to organise architectures in the present industry and highlights rather glaringly the missing piece in all of them - the deliberate effort to ensure the output of the work is simple. The next two chapters quickly move on present some simple real-world scenarios (like a rubik's cube, chess games, team and store organisation, etc) and then the math behind them, on how dividing them - partitioning - into smaller pieces of a bigger whole helps to solve the problem they present in a much less troublesome manner. The mathematics introduced is simple enough to understand and convincing. But somehow the lessons would be re-taught every now and then; I found the repeated explanations to be redundant and approaching incessant. It is almost as though the author fears the readers may not be convinced enough and needed reminders. Or there is the assumption the intended audience largely failed elementary math in school. As convincing as the principles behind the math are, my disappointment set in when the transition from pure math theory into real-world business modeling began. If you think it sounded too good to be true that real-world architecture can be tackled with simplistic mathematical models, well, it is. Even Roger Sessions himself admits that real-world circumstances is in fact, not that simple. The problem with the absolute black-white nature of mathematical theory is it excludes many (grey) inter-object relationships or channels that real-world organisations would inherently possess; they cannot be blindly ignored. Take for example, the Five Laws of Partitions First Law of Partitions - Partitions must be true partitions. Second Law of Partitions - Partition definit

Techniques for high-leverage complexity management

When building software it is often difficult to step back from the complexity of the solution and consider the big picture -- how the software will fit into the real world. Managing this complexity is a major challenge for the industry. Simple Architectures for Complex Enterprises addresses how to manage complexity in IT systems at the top level of design, Enterprise Architecture (EA). EA describes how software and processes fit together to provide value to users. Whether EA is more about "design", "requirements", or something else is less important than the idea that the highest leverage place to manage complexity is in the big-picture "systems" perspective that transcends software details.(e.g., what software pieces should be built/bought and what should they do?) The book lays out some context and history for EA in chapter 1 (35 pages), and then spends chapters 2-4 (70 pages) laying the foundation for complexity management techniques. The author's core EA process (called SIP) is described in chapter 5 (20 pages). Chapter 6 (15 pages) is a detailed case study of a troubled reengineering of the UK's health care IT systems. Chapter 7 (10 pages) is a mapping of the complexity management ideas onto an SOA model from the author's previous work, described as the "software fortress" approach. Depending on your background and experience level, some parts may be slow or of limited value. However the book's structure allows you to skip over areas that are bogging down without missing value later on. In particular: - You don't need to immerse yourself in the descriptions of existing EA models in the second half of chapter 1. - If you are comfortable with probability, equivalency sets, and partitioning, you can skim and skip over much of chapters 2, 3, and 4. There is good primer material in these sections, although the prose is a bit drawn out in places. - The SIP process can come across as a prescriptive sliver-bullet. The author does caveat the importance of artistic application, but this can seem drowned out at times. Ultimately the book wins by providing starting points for practitioners to keep business systems simple and partitioned at the highest points of leverage. Although many of the underlying ideas are not new, they are packaged in an accessible, logical way. The case studies, references to current industry debacles, and the authors personal experiences are valuable on their own and make the work an engaging read.

Architectural Common Sense

I have managed to talk to quite a few good software/enterprise architects over the years. When I do, the issues that we often talk about most are simplicity of design and how to manage complexity. In general, understanding that the management of complexity is the fundamental task of architecture is what defines a good architect. This book indicates that Roger really gets this issue. He also seems to get the business alignment issues that are sometimes lacking from architecture texts. From Roger's advice on partitioning a solution to his advice on implementing a system using an incremental approach everything here is sound and well articulated. This book is a short read but almost definitely worth your time if you are building anything in software from an enterprise down. Much of the principles he professes are the same principles that are important in regular software architecture. Components and object oriented design are merely methods of figuring out internal equivalence classes and appropriately partitioning solutions. Iterative development and some of the new agile principles are based on the same idea he advocates for the enterprise, incremental delivery. If for nothing else, this book is useful because Sessions is very successful in mathematically proving that many of his ideas should work. Most texts advocating incremental methodologies or problem decomposition can sound evangelical. This book does not. Overall, SIP sounds like it is a very good foundation for a company's enterprise architecture. That said, I am sure my advice would mean more if I did enterprise architecture. I hope that it is merely enough to say this.. I am in software development. I have helped provide or provided the technical architecure on quite a few projects. I feel that in general Roger has the core concerns nailed with his book.