Udi Dahan   Udi Dahan – The Software Simplist
Enterprise Development Expert & SOA Specialist
 
  
    Blog Consulting Training Articles Speaking About
  

Non-functional Architectural Woes

Tuesday, January 12th, 2010.

Non-functional architecture
As I sit here in the lounge at Bogota airport waiting for my delayed flight, I remembered something interesting that came up in my 2-week training/consulting in Cali. It’s not a question that came up, or anything like that. It was that I suddenly noticed a pattern in many of my consulting and training clients over the past years. And as I thought about it, I realized that it was prevalent in our industry as a whole – in the literature, on the web, everywhere.

It’s how people think about functional and non-functional requirements.

The problem with categorization

There’s nothing wrong with categorizing requirements as either functional or non-functional.

The problem is that people project that categorization from the problem domain to the solution domain as well.

There is an impression that architecture and technology choices are, to a large extent, based on non-functional requirements, and only on non-functional requirements.

Here are some examples:

Extensibility: Workflow/BPM engine , DSL, Plug-in framework, etc
Scalability: Message/Service Bus, Database (NoSQL camp, I’m looking at you too), etc
High Availability: See scalability

Too many times have I noticed architects so focused on these issues that they all but ignore the functional requirements and the business objectives of the stakeholders.

Not to place an unfair portion of the blame there, the vendors have been perpetuating the above fallacies to sell more and/or new products. Given the enormous influence of the big vendors (conferences, training, etc) it isn’t any wonder that architects in the field use the vendors’ “best practices”.

The problem that arises from this kind of thinking is a shoe-horning of functional requirements into the architecture decided upon entirely in the context of non-functional requirements.

Functional Earthquakes

Stable architecture cannot be created based entirely on non-functional requirements. There are functional requirements that can shake the foundation of a technically-oriented architecture.

Let’s take the canonical layered architecture with its normalized database. Now we get a new requirement in the form of:

“As a supplier, when I log-in, I want to see on my home page my most recent purchase orders, grouped by highest value retailer (total historical purchase order value), sorted according to requested time of delivery.”

In order for a developer to implement this according to the architectural guidelines of normalization and layering here’s what they do: join retailers who have an agreement with the supplier (join between supplier, retailer, and agreement tables), join the purchase orders and their lines, (ignoring tax for now), sum the line value and group by retailer, and use as an input to the purchase order table joining again, filter in last 24 hours, sort by time of delivery.

So, in our normalized database, we have many millions of purchase orders, hundreds of millions of lines, that we’re joining against each other as well as several other tables.

After this new feature has been implemented, any time a supplier sees their home page, the system stops accepting purchase orders until the home page has been rendered several minutes later.

Can we really say that our architecture is stable if a single functional requirement can undo all of it’s non-functional properties?

Obviously not – but the question the architect (and his boss) are asking is, how did this happen? And if it happened once, can it happen again?

Lessons Learned – sorta

So a reporting database is introduced so that all complex queries like those performed above won’t prevent the system from accepting new purchase orders. A nightly batch moves data from the normalized DB to the reporting DB. Sounds good – non-functionally.

And then a new requirement comes in for handling rush-orders.

So we do an hourly batch. But now these batches start to cause hiccups to our transactional system, which gets backed up, and when released, allocates many more threads to deal with the pending load, and the increased concurrency in the databases sharply increases the number of deadlocks, further backing up the system, until the system becomes effectively unavailable.

Can this be happening again? A functional requirement undoing all of our technically elegant non-functional architectural decisions?

Now what?

The technology is blamed. We should have never counted on SQL Server to handle our kind of *enterprise* requirements. Let’s move to Oracle – it’s *unbreakable*. (Several months and functionalities later) We should have never counted on a database to handle our kind of enterprise requirements. Let’s introduce an *Enterprise Service Bus*. (Several months and functionalities later) We should have never counted on our internal IT to host this. Let’s move to *The Cloud*. (Several months and functionalities later, looking at the bill from our cloud provider) We should have never used .NET for our application because it requires the more expensive Windows cloud. Let’s rewrite on Linux to reduce our cloud costs.

By this time, all the people who originally worked on the project aren’t there anymore. And the cycle continues with limited memory of where we started and how we got here.

Soon, soon, we’ll find that non-functional silver bullet that will make all of our problems go away.

These are not the droids you are looking for

They really aren’t.

If we want our architecture to be stable, we need to base it on stable abstractions. The only thing is that there aren’t any inherently stable abstractions in the solution domain (as we’ve had the chance to witness). That really only leaves one other place to look for them – in the problem domain, also known as the functional requirements.

But functional requirements change all the time! Wasn’t that what got us into this mess to begin with?

Indeed, but in between the functional requirements and behind them is something that is quite stable: the stakeholders business objectives.

The supply chain will continue to strive to optimize itself. To shorten the time for an order to be fulfilled. To decrease the amount of inventory that a retailer holds. To choose the best set of suppliers for our product catalog. To recognize which retailers give me the most business and serve them better. To identify high potential retailers – big retailers (like Walmart) who aren’t buying as much from me as other retailers.

This is how the business has been done for decades and will continue to be done for decades more.

If we could find a way to capture those stable elements and represent them as core elements in our architectural structure, and then balance the non-functional requirements within those functional contexts, maybe, just maybe, our architecture will stand the test of time.

More to come…

  
If you liked this article, you might also like articles in these categories:


Check out my Best Content If you've got a minute, you might enjoy taking a look at some of my best articles.
I've gone through the hundreds of articles I've written over the past 6 years and put together a list of the best ones as ranked by my 5000+ readers.
You won't be disappointed.

Subscribe to my feedIf you'd like to get new articles sent to you when they're published, it's easy and free.
Subscribe right here.

Follow me on Twitter Follow me on Twitter @UdiDahan.



Something on your mind? Got a question? I'd be thrilled to hear it.
Leave a comment below or email me, whatever works for you.

27 Comments

  1. Bjarte Says:

    The process of jumping between different technical solutions to fulfil the non-functional requirements while the functional requirements are changing is probably one of the most common ways to spend too much money on a software project.

    I’m looking forward to the post where you will reveal how we connect the dots between the business goals and our architecture 😉

    Thx for another great post.


  2. DaRage Says:

    Problem domain, solution domain reminds of Object Thinking book of David West. Lately I’ve been noticing more post like this one calling for the return to the basics of object-oriented ideas.


  3. David Nelson Says:

    “…in between the functional requirements and behind them is something that is quite stable: the stakeholders business objectives.”

    I envy you the industries and environments you work in where the business objectives have actually remained stable over the course of even a single software project. That has certainly not been my experience.


  4. Kamran Saleemi Says:

    Definitely one of your most incisive posts …


  5. udidahan Says:

    Bjarte,

    Glad you liked it.


  6. udidahan Says:

    DaRage,

    Indeed – we have to walk before we run 🙂


  7. udidahan Says:

    David,

    I think we need to differentiate between the “business objectives” for the software project, and the actual business objectives of the stakeholders – usually expressed in language not related to software at all.

    If you could describe your environment, maybe I could help identify a stable stakeholder objective?


  8. Steve Degosserie Says:

    Very interesting article as always. Do you think DDD (focus on the problem domain first) & Strategic Design (identify & focus on what brings the most business value) provide a partial answer to his problem ?


  9. Gary A Says:

    It all goes back to what you consider a requirement is:

    The requirement ‘As a supplier, when I log-in, I want to see on my home page my most recent purchase orders,..’ is a software requirement. It’s something the sofware must do.

    The business requirement is something like ‘To shorten the time for an order to be fulfilled.’ Or business objective.

    The input to architecture decisions are the business requirements – not the software requirements, which come later once you’ve determined what the solution is.

    Too often we just don’t do business requirements. Or we take software requirements from users and call them business requirements because they cme from the business. That’s where the problem is.


  10. udidahan Says:

    Gary,

    It sounds like we’re very much in agreement.

    I’d say that ‘shortening the time for an order to be fulfilled’ is an ongoing business objective that is the spirit behind many specific software requirements that we may get.

    The question that I intend to address in my next post is how we take this business objectives (requirements) and capture them in our software architecture.

    Thanks for your comments.


  11. Jean-Jacques Dubray Says:

    Udi,

    >> the only thing is that there aren’t any inherently stable
    >> abstractions in the solution domain (as we’ve had the chance to
    >> witness).

    That’s because you rely on vendors for these abstractions. I think it is time to develop a stable (Architecture independent – not just technology independent) set of Solution Abstractions.

    I have described how to go about that in a generic way here: http://www.infoq.com/articles/mop

    The problem with traditional approaches, UML, EMF or now SSM is that somehow they are anchored in OO, i.e the concept of “Class” is at the center of the M3 layer. I was hoping SSM would change that, but they did not. The irony and tragedy is that none of the “solution abstraction” can be efficiently described with an OO foundation.

    So if you go int the problem space and try to create abstractions there, you’ll run into the exact same problem because all models are built on sand, i.e. OO.


  12. Jean-Jacques Dubray Says:

    Udi,

    I have developed a more elaborate response here: http://www.ebpml.org/blog/212.htm

    JJ-


  13. Bogdan Nedelcu Says:

    Very deep you thoughts are.

    Shall we ever be able to represent business knowledge in a structured/programmable way or shall we always concentrate on the ability to change our software according to the always changing functional requirements.

    We, as humans, are able to represent in our minds the concepts, the domain, we are able to expose parts of it to the outside world, but even the most skilled of us are in difficulty to well formalize these concepts.

    Indeed business is done in the same way for decades, business as a whole. Some business objectives are the same and some are very particular. It is why extracting the architectural artifacts from the functional requirements is difficult.

    Is it true that one business objective resembles to its business area, but is somehow particular ? Is it true the more you add businesses objectives together the more they look like the whole ? Is that why we can easily formalize business theory and hardly manage to formalize a running business ?

    These were my questions. One could answer that the solution is related to fractal theory.

    Looking forward to “more to come…”


  14. Jean-Jacques Dubray Says:

    >> shall we always concentrate on the ability to change our software
    >> according to the always changing functional requirements.
    This sounds easier that the former, and possibly good enough

    >> but even the most skilled of us are in difficulty to well formalize
    >> these concepts.
    This comes from the fact that the current modelling paradigm is “OO” based and surprisingly does not integrate behavior. All models are reduced to elements with attributes and references to each other. “Behavior” is strangely left to be under the hood in the metadata interpreter or compiler. So you are left to describe “behavior-less” models (on the problem or solution side). This is wrong.


  15. Jean-Jacques Dubray Says:

    I don’t know if you have seen that post too: http://friends.praxeme.org/2009/08/get-out-of-the-immaturity-model-part-2/

    I think that’s fairly relevant to what you are attempting to achieve.

    JJ-


  16. Bogdan Nedelcu Says:

    @Jean-Jaque when speaking about difficulty to formalize I am not necessarly refering to OO concepts, rather to put in any kind of theoretical model a certain business case. I’m not sure a programming language is a solution to this problem, nor the current business modelling tools, nor that it is even possible.
    Let’s see what Udi has to say about that.

    I detailed my ideas here http://www.dependnet.ro/blog/post/2010/01/17/Business-Objectives-as-key-architectural-pillars-doubled-by-fractal-inspiration.aspx


  17. Steve Says:

    At what point does accountability of the crazy req start? They can’t live in a vacuum of not understanding the impact their req have on the system

    I’m playing a bit of devils advocate here…


  18. udidahan Says:

    Bogdan,

    > Is it true that one business objective resembles to its business area, but is somehow particular ?

    Business objectives can usually be sourced to a single stakeholder – someone who is measured a certain way by the organization around them. Our goal is to find them.

    > Is it true the more you add businesses objectives together the more they look like the whole ?

    Not exactly sure what you mean by this, but I’m feeling that the answer is no. We need to find which objectives go to different stakeholders, and then decouple their implementations in software.

    > Is that why we can easily formalize business theory and hardly manage to formalize a running business ?

    I don’t think that we can easily formalize business theory, but agree that there is difficulty in modeling (let alone formalizing) a running business. The larger the business, the more likely it’s undergoing some reorganization, merger, acquisition, entrance into a new market, exit from some other market, etc. The goal is to identify those elements and segregate their implementations from those parts which represent more stable parts of the business.

    Hope that answers your questions.


  19. udidahan Says:

    JJ,

    After reading your post and the comments above, I think that this quote can serve as a kind of summary of your position (please correct me if I’ve over-simplified):

    “This particular rash of BPM products built their business on the fallacy that you could somehow build solutions directly from ‘problem-side abstractions’.”

    Note that in my post, I didn’t say to build the solution DIRECTLY from the “problem-side abstractions”. I said that we need to capture certain *stable* elements of the problem domain and have them represented explicitly in the solution domain. At that point, we can continue with good solution domain practices and avoid many of the situations described in my post.


  20. udidahan Says:

    Steve,

    “At what point does accountability of the crazy req start?”

    I do believe your horns are showing, Mr. Devil’s advocate 🙂

    Are those requirements really that crazy? If we had developed the system differently and it were easy for us to implement those requirements, would they not be crazy then? Is it the business’ fault that they didn’t give us these requirements up-front?

    OMG – are we going back to big requirements up-front to avoid these problems?

    We’re going to find the right balance between all these things – hang in there 🙂


  21. Kyle Szklenski Says:

    This was another great post, as usual. I’m looking forward to the next one on this topic as well. This is one of the biggest problems that I run into with clients today.

    When working with other programmers, it’s often the case that they tend to think that it’s more important what specific tools you’re using, rather than how you use them and what you use them for. For example, someone once told me that it’s important to be *really* good with ReSharper, because it will help you build your designs effectively. I’m a RS ninja, and I categorically disagreed with him – that is, I told him why it neither helps nor hurts a design, and should *not* help or hurt design. It would be good to have tools to help design, but it’s still fundamentally a human problem, I think. Naturally, that same person said that it’s only if you’re using TypeMock that you can really design a real system.

    Finally, I’ve found lately an MVVM craze that forgets the first piece of the pattern: the model. The models are trash, but they have these “elegant” view-models that make it easy to tie themselves in knots.

    Sorry, this turned into a bit o’ the rant. Good post, Udi. 🙂


  22. udidahan Says:

    Kyle,

    Glad you liked it.


  23. mohan Says:

    what is the real time examples of functional and non functional requirements?


  24. udidahan Says:

    Mohan,

    What do you mean by “real time” ?


  25. A CQRS Journey – with and without Microsoft Says:

    […] The effects of this lack of alignment may be felt only much later in the project, when we get a requirement that just doesn’t fit the architecture we’ve set up. I’ve blogged about the symptoms of this problem about 2 years ago in my post Non-functional architectural woes. […]


  26. Tom Gilb Says:

    Of course quality and performance requirements are major architecture drives, along with constraints (costs, legal, culture).

    If someone wants some free deep technology on this see my downloads at gilb.com

    http://www.gilb.com/tiki-download_file.php?fileId=480
    Real Architecture. Slides for Javazone Sept. 8 2011
    http://vimeo.com/28763240 Video

    http://vimeo.com/28763240
    Video of Javazone Presentation

    If someone is deeply serious, email me and I’ll send you a free digital copy of my CE book which has all the language tools to deal with this.
    Tom


  27. udidahan Says:

    Tom,

    I like your “Real Architecture” slides.


Your comment...



If this is your first time commenting, it may take a while to show up.
I'm working to make that better.

Subscribe here to receive updates on comments.
  
   


Don't miss my best content
 

Recommendations

Bryan Wheeler, Director Platform Development at msnbc.com
Udi Dahan is the real deal.

We brought him on site to give our development staff the 5-day “Advanced Distributed System Design” training. The course profoundly changed our understanding and approach to SOA and distributed systems.

Consider some of the evidence: 1. Months later, developers still make allusions to concepts learned in the course nearly every day 2. One of our developers went home and made her husband (a developer at another company) sign up for the course at a subsequent date/venue 3. Based on what we learned, we’ve made constant improvements to our architecture that have helped us to adapt to our ever changing business domain at scale and speed If you have the opportunity to receive the training, you will make a substantial paradigm shift.

If I were to do the whole thing over again, I’d start the week by playing the clip from the Matrix where Morpheus offers Neo the choice between the red and blue pills. Once you make the intellectual leap, you’ll never look at distributed systems the same way.

Beyond the training, we were able to spend some time with Udi discussing issues unique to our business domain. Because Udi is a rare combination of a big picture thinker and a low level doer, he can quickly hone in on various issues and quickly make good (if not startling) recommendations to help solve tough technical issues.” November 11, 2010

Sam Gentile Sam Gentile, Independent WCF & SOA Expert
“Udi, one of the great minds in this area.
A man I respect immensely.”





Ian Robinson Ian Robinson, Principal Consultant at ThoughtWorks
"Your blog and articles have been enormously useful in shaping, testing and refining my own approach to delivering on SOA initiatives over the last few years. Over and against a certain 3-layer-application-architecture-blown-out-to- distributed-proportions school of SOA, your writing, steers a far more valuable course."

Shy Cohen Shy Cohen, Senior Program Manager at Microsoft
“Udi is a world renowned software architect and speaker. I met Udi at a conference that we were both speaking at, and immediately recognized his keen insight and razor-sharp intellect. Our shared passion for SOA and the advancement of its practice launched a discussion that lasted into the small hours of the night.
It was evident through that discussion that Udi is one of the most knowledgeable people in the SOA space. It was also clear why – Udi does not settle for mediocrity, and seeks to fully understand (or define) the logic and principles behind things.
Humble yet uncompromising, Udi is a pleasure to interact with.”

Glenn Block Glenn Block, Senior Program Manager - WCF at Microsoft
“I have known Udi for many years having attended his workshops and having several personal interactions including working with him when we were building our Composite Application Guidance in patterns & practices. What impresses me about Udi is his deep insight into how to address business problems through sound architecture. Backed by many years of building mission critical real world distributed systems it is no wonder that Udi is the best at what he does. When customers have deep issues with their system design, I point them Udi's way.”

Karl Wannenmacher Karl Wannenmacher, Senior Lead Expert at Frequentis AG
“I have been following Udi’s blog and podcasts since 2007. I’m convinced that he is one of the most knowledgeable and experienced people in the field of SOA, EDA and large scale systems.
Udi helped Frequentis to design a major subsystem of a large mission critical system with a nationwide deployment based on NServiceBus. It was impressive to see how he took the initial architecture and turned it upside down leading to a very flexible and scalable yet simple system without knowing the details of the business domain. I highly recommend consulting with Udi when it comes to large scale mission critical systems in any domain.”

Simon Segal Simon Segal, Independent Consultant
“Udi is one of the outstanding software development minds in the world today, his vast insights into Service Oriented Architectures and Smart Clients in particular are indeed a rare commodity. Udi is also an exceptional teacher and can help lead teams to fall into the pit of success. I would recommend Udi to anyone considering some Architecural guidance and support in their next project.”

Ohad Israeli Ohad Israeli, Chief Architect at Hewlett-Packard, Indigo Division
“When you need a man to do the job Udi is your man! No matter if you are facing near deadline deadlock or at the early stages of your development, if you have a problem Udi is the one who will probably be able to solve it, with his large experience at the industry and his widely horizons of thinking , he is always full of just in place great architectural ideas.
I am honored to have Udi as a colleague and a friend (plus having his cell phone on my speed dial).”

Ward Bell Ward Bell, VP Product Development at IdeaBlade
“Everyone will tell you how smart and knowledgable Udi is ... and they are oh-so-right. Let me add that Udi is a smart LISTENER. He's always calibrating what he has to offer with your needs and your experience ... looking for the fit. He has strongly held views ... and the ability to temper them with the nuances of the situation.
I trust Udi to tell me what I need to hear, even if I don't want to hear it, ... in a way that I can hear it. That's a rare skill to go along with his command and intelligence.”

Eli Brin, Program Manager at RISCO Group
“We hired Udi as a SOA specialist for a large scale project. The development is outsourced to India. SOA is a buzzword used almost for anything today. We wanted to understand what SOA really is, and what is the meaning and practice to develop a SOA based system.
We identified Udi as the one that can put some sense and order in our minds. We started with a private customized SOA training for the entire team in Israel. After that I had several focused sessions regarding our architecture and design.
I will summarize it simply (as he is the software simplist): We are very happy to have Udi in our project. It has a great benefit. We feel good and assured with the knowledge and practice he brings. He doesn’t talk over our heads. We assimilated nServicebus as the ESB of the project. I highly recommend you to bring Udi into your project.”

Catherine Hole Catherine Hole, Senior Project Manager at the Norwegian Health Network
“My colleagues and I have spent five interesting days with Udi - diving into the many aspects of SOA. Udi has shown impressive abilities of understanding organizational challenges, and has brought the business perspective into our way of looking at services. He has an excellent understanding of the many layers from business at the top to the technical infrstructure at the bottom. He is a great listener, and manages to simplify challenges in a way that is understandable both for developers and CEOs, and all the specialists in between.”

Yoel Arnon Yoel Arnon, MSMQ Expert
“Udi has a unique, in depth understanding of service oriented architecture and how it should be used in the real world, combined with excellent presentation skills. I think Udi should be a premier choice for a consultant or architect of distributed systems.”

Vadim Mesonzhnik, Development Project Lead at Polycom
“When we were faced with a task of creating a high performance server for a video-tele conferencing domain we decided to opt for a stateless cluster with SQL server approach. In order to confirm our decision we invited Udi.

After carefully listening for 2 hours he said: "With your kind of high availability and performance requirements you don’t want to go with stateless architecture."

One simple sentence saved us from implementing a wrong product and finding that out after years of development. No matter whether our former decisions were confirmed or altered, it gave us great confidence to move forward relying on the experience, industry best-practices and time-proven techniques that Udi shared with us.
It was a distinct pleasure and a unique opportunity to learn from someone who is among the best at what he does.”

Jack Van Hoof Jack Van Hoof, Enterprise Integration Architect at Dutch Railways
“Udi is a respected visionary on SOA and EDA, whose opinion I most of the time (if not always) highly agree with. The nice thing about Udi is that he is able to explain architectural concepts in terms of practical code-level examples.”

Neil Robbins Neil Robbins, Applications Architect at Brit Insurance
“Having followed Udi's blog and other writings for a number of years I attended Udi's two day course on 'Loosely Coupled Messaging with NServiceBus' at SkillsMatter, London.

I would strongly recommend this course to anyone with an interest in how to develop IT systems which provide immediate and future fitness for purpose. An influential and innovative thought leader and practitioner in his field, Udi demonstrates and shares a phenomenally in depth knowledge that proves his position as one of the premier experts in his field globally.

The course has enhanced my knowledge and skills in ways that I am able to immediately apply to provide benefits to my employer. Additionally though I will be able to build upon what I learned in my 2 days with Udi and have no doubt that it will only enhance my future career.

I cannot recommend Udi, and his courses, highly enough.”

Nick Malik Nick Malik, Enterprise Architect at Microsoft Corporation
You are an excellent speaker and trainer, Udi, and I've had the fortunate experience of having attended one of your presentations. I believe that you are a knowledgable and intelligent man.”

Sean Farmar Sean Farmar, Chief Technical Architect at Candidate Manager Ltd
“Udi has provided us with guidance in system architecture and supports our implementation of NServiceBus in our core business application.

He accompanied us in all stages of our development cycle and helped us put vision into real life distributed scalable software. He brought fresh thinking, great in depth of understanding software, and ongoing support that proved as valuable and cost effective.

Udi has the unique ability to analyze the business problem and come up with a simple and elegant solution for the code and the business alike.
With Udi's attention to details, and knowledge we avoided pit falls that would cost us dearly.”

Børge Hansen Børge Hansen, Architect Advisor at Microsoft
“Udi delivered a 5 hour long workshop on SOA for aspiring architects in Norway. While keeping everyone awake and excited Udi gave us some great insights and really delivered on making complex software challenges simple. Truly the software simplist.”

Motty Cohen, SW Manager at KorenTec Technologies
“I know Udi very well from our mutual work at KorenTec. During the analysis and design of a complex, distributed C4I system - where the basic concepts of NServiceBus start to emerge - I gained a lot of "Udi's hours" so I can surely say that he is a professional, skilled architect with fresh ideas and unique perspective for solving complex architecture challenges. His ideas, concepts and parts of the artifacts are the basis of several state-of-the-art C4I systems that I was involved in their architecture design.”

Aaron Jensen Aaron Jensen, VP of Engineering at Eleutian Technology
Awesome. Just awesome.

We’d been meaning to delve into messaging at Eleutian after multiple discussions with and blog posts from Greg Young and Udi Dahan in the past. We weren’t entirely sure where to start, how to start, what tools to use, how to use them, etc. Being able to sit in a room with Udi for an entire week while he described exactly how, why and what he does to tackle a massive enterprise system was invaluable to say the least.

We now have a much better direction and, more importantly, have the confidence we need to start introducing these powerful concepts into production at Eleutian.”

Gad Rosenthal Gad Rosenthal, Department Manager at Retalix
“A thinking person. Brought fresh and valuable ideas that helped us in architecting our product. When recommending a solution he supports it with evidence and detail so you can successfully act based on it. Udi's support "comes on all levels" - As the solution architect through to the detailed class design. Trustworthy!”

Chris Bilson Chris Bilson, Developer at Russell Investment Group
“I had the pleasure of attending a workshop Udi led at the Seattle ALT.NET conference in February 2009. I have been reading Udi's articles and listening to his podcasts for a long time and have always looked to him as a source of advice on software architecture.
When I actually met him and talked to him I was even more impressed. Not only is Udi an extremely likable person, he's got that rare gift of being able to explain complex concepts and ideas in a way that is easy to understand.
All the attendees of the workshop greatly appreciate the time he spent with us and the amazing insights into service oriented architecture he shared with us.”

Alexey Shestialtynov Alexey Shestialtynov, Senior .Net Developer at Candidate Manager
“I met Udi at Candidate Manager where he was brought in part-time as a consultant to help the company make its flagship product more scalable. For me, even after 30 years in software development, working with Udi was a great learning experience. I simply love his fresh ideas and architecture insights.
As we all know it is not enough to be armed with best tools and technologies to be successful in software - there is still human factor involved. When, as it happens, the project got in trouble, management asked Udi to step into a leadership role and bring it back on track. This he did in the span of a month. I can only wish that things had been done this way from the very beginning.
I look forward to working with Udi again in the future.”

Christopher Bennage Christopher Bennage, President at Blue Spire Consulting, Inc.
“My company was hired to be the primary development team for a large scale and highly distributed application. Since these are not necessarily everyday requirements, we wanted to bring in some additional expertise. We chose Udi because of his blogging, podcasting, and speaking. We asked him to to review our architectural strategy as well as the overall viability of project.
I was very impressed, as Udi demonstrated a broad understanding of the sorts of problems we would face. His advice was honest and unbiased and very pragmatic. Whenever I questioned him on particular points, he was able to backup his opinion with real life examples. I was also impressed with his clarity and precision. He was very careful to untangle the meaning of words that might be overloaded or otherwise confusing. While Udi's hourly rate may not be the cheapest, the ROI is undoubtedly a deal. I would highly recommend consulting with Udi.”

Robert Lewkovich, Product / Development Manager at Eggs Overnight
“Udi's advice and consulting were a huge time saver for the project I'm responsible for. The $ spent were well worth it and provided me with a more complete understanding of nServiceBus and most importantly in helping make the correct architectural decisions earlier thereby reducing later, and more expensive, rework.”

Ray Houston Ray Houston, Director of Development at TOPAZ Technologies
“Udi's SOA class made me smart - it was awesome.

The class was very well put together. The materials were clear and concise and Udi did a fantastic job presenting it. It was a good mixture of lecture, coding, and question and answer. I fully expected that I would be taking notes like crazy, but it was so well laid out that the only thing I wrote down the entire course was what I wanted for lunch. Udi provided us with all the lecture materials and everyone has access to all of the samples which are in the nServiceBus trunk.

Now I know why Udi is the "Software Simplist." I was amazed to find that all the code and solutions were indeed very simple. The patterns that Udi presented keep things simple by isolating complexity so that it doesn't creep into your day to day code. The domain code looks the same if it's running in a single process or if it's running in 100 processes.”

Ian Cooper Ian Cooper, Team Lead at Beazley
“Udi is one of the leaders in the .Net development community, one of the truly smart guys who do not just get best architectural practice well enough to educate others but drives innovation. Udi consistently challenges my thinking in ways that make me better at what I do.”

Liron Levy, Team Leader at Rafael
“I've met Udi when I worked as a team leader in Rafael. One of the most senior managers there knew Udi because he was doing superb architecture job in another Rafael project and he recommended bringing him on board to help the project I was leading.
Udi brought with him fresh solutions and invaluable deep architecture insights. He is an authority on SOA (service oriented architecture) and this was a tremendous help in our project.
On the personal level - Udi is a great communicator and can persuade even the most difficult audiences (I was part of such an audience myself..) by bringing sound explanations that draw on his extensive knowledge in the software business. Working with Udi was a great learning experience for me, and I'll be happy to work with him again in the future.”

Adam Dymitruk Adam Dymitruk, Director of IT at Apara Systems
“I met Udi for the first time at DevTeach in Montreal back in early 2007. While Udi is usually involved in SOA subjects, his knowledge spans all of a software development company's concerns. I would not hesitate to recommend Udi for any company that needs excellent leadership, mentoring, problem solving, application of patterns, implementation of methodologies and straight out solution development.
There are very few people in the world that are as dedicated to their craft as Udi is to his. At ALT.NET Seattle, Udi explained many core ideas about SOA. The team that I brought with me found his workshop and other talks the highlight of the event and provided the most value to us and our organization. I am thrilled to have the opportunity to recommend him.”

Eytan Michaeli Eytan Michaeli, CTO Korentec
“Udi was responsible for a major project in the company, and as a chief architect designed a complex multi server C4I system with many innovations and excellent performance.”


Carl Kenne Carl Kenne, .Net Consultant at Dotway AB
“Udi's session "DDD in Enterprise apps" was truly an eye opener. Udi has a great ability to explain complex enterprise designs in a very comprehensive and inspiring way. I've seen several sessions on both DDD and SOA in the past, but Udi puts it in a completly new perspective and makes us understand what it's all really about. If you ever have a chance to see any of Udi's sessions in the future, take it!”

Avi Nehama, R&D Project Manager at Retalix
“Not only that Udi is a briliant software architecture consultant, he also has remarkable abilities to present complex ideas in a simple and concise manner, and...
always with a smile. Udi is indeed a top-league professional!”

Ben Scheirman Ben Scheirman, Lead Developer at CenterPoint Energy
“Udi is one of those rare people who not only deeply understands SOA and domain driven design, but also eloquently conveys that in an easy to grasp way. He is patient, polite, and easy to talk to. I'm extremely glad I came to his workshop on SOA.”

Scott C. Reynolds Scott C. Reynolds, Director of Software Engineering at CBLPath
“Udi is consistently advancing the state of thought in software architecture, service orientation, and domain modeling.
His mastery of the technologies and techniques is second to none, but he pairs that with a singular ability to listen and communicate effectively with all parties, technical and non, to help people arrive at context-appropriate solutions. Every time I have worked with Udi, or attended a talk of his, or just had a conversation with him I have come away from it enriched with new understanding about the ideas discussed.”

Evgeny-Hen Osipow, Head of R&D at PCLine
“Udi has helped PCLine on projects by implementing architectural blueprints demonstrating the value of simple design and code.”

Rhys Campbell Rhys Campbell, Owner at Artemis West
“For many years I have been following the works of Udi. His explanation of often complex design and architectural concepts are so cleanly broken down that even the most junior of architects can begin to understand these concepts. These concepts however tend to typify the "real world" problems we face daily so even the most experienced software expert will find himself in an "Aha!" moment when following Udi teachings.
It was a pleasure to finally meet Udi in Seattle Alt.Net OpenSpaces 2008, where I was pleasantly surprised at how down-to-earth and approachable he was. His depth and breadth of software knowledge also became apparent when discussion with his peers quickly dove deep in to the problems we current face. If given the opportunity to work with or recommend Udi I would quickly take that chance. When I think .Net Architecture, I think Udi.”

Sverre Hundeide Sverre Hundeide, Senior Consultant at Objectware
“Udi had been hired to present the third LEAP master class in Oslo. He is an well known international expert on enterprise software architecture and design, and is the author of the open source messaging framework nServiceBus. The entire class was based on discussion and interaction with the audience, and the only Power Point slide used was the one showing the agenda.
He started out with sketching a naive traditional n-tier application (big ball of mud), and based on suggestions from the audience we explored different solutions which might improve the solution. Whatever suggestions we threw at him, he always had a thoroughly considered answer describing pros and cons with the suggested solution. He obviously has a lot of experience with real world enterprise SOA applications.”

Raphaël Wouters Raphaël Wouters, Owner/Managing Partner at Medinternals
“I attended Udi's excellent course 'Advanced Distributed System Design with SOA and DDD' at Skillsmatter. Few people can truly claim such a high skill and expertise level, present it using a pragmatic, concrete no-nonsense approach and still stay reachable.”

Nimrod Peleg Nimrod Peleg, Lab Engineer at Technion IIT
“One of the best programmers and software engineer I've ever met, creative, knows how to design and implemet, very collaborative and finally - the applications he designed implemeted work for many years without any problems!

Jose Manuel Beas
“When I attended Udi's SOA Workshop, then it suddenly changed my view of what Service Oriented Architectures were all about. Udi explained complex concepts very clearly and created a very productive discussion environment where all the attendees could learn a lot. I strongly recommend hiring Udi.”

Daniel Jin Daniel Jin, Senior Lead Developer at PJM Interconnection
“Udi is one of the top SOA guru in the .NET space. He is always eager to help others by sharing his knowledge and experiences. His blog articles often offer deep insights and is a invaluable resource. I highly recommend him.”

Pasi Taive Pasi Taive, Chief Architect at Tieto
“I attended both of Udi's "UI Composition Key to SOA Success" and "DDD in Enterprise Apps" sessions and they were exceptionally good. I will definitely participate in his sessions again. Udi is a great presenter and has the ability to explain complex issues in a manner that everyone understands.”

Eran Sagi, Software Architect at HP
“So far, I heard about Service Oriented architecture all over. Everyone mentions it – the big buzz word. But, when I actually asked someone for what does it really mean, no one managed to give me a complete satisfied answer. Finally in his excellent course “Advanced Distributed Systems”, I got the answers I was looking for. Udi went over the different motivations (principles) of Services Oriented, explained them well one by one, and showed how each one could be technically addressed using NService bus. In his course, Udi also explain the way of thinking when coming to design a Service Oriented system. What are the questions you need to ask yourself in order to shape your system, place the logic in the right places for best Service Oriented system.

I would recommend this course for any architect or developer who deals with distributed system, but not only. In my work we do not have a real distributed system, but one PC which host both the UI application and the different services inside, all communicating via WCF. I found that many of the architecture principles and motivations of SOA apply for our system as well. Enough that you have SW partitioned into components and most of the principles becomes relevant to you as well. Bottom line – an excellent course recommended to any SW Architect, or any developer dealing with distributed system.”

Consult with Udi

Guest Authored Books



Creative Commons License  © Copyright 2005-2011, Udi Dahan. email@UdiDahan.com