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QCon London 2013 – Simplicity, complexity and doodles

March 21st, 2013 by

Westminster Abbey

Westminster Abbey – View from the Queen Elizabeth II conference center

…and now back home

On my desk lies a stack of notepads from the QCon sponsors. I pick up one of them and turn few pages trying to decipher my own handwriting. As I read my notes I reflect back on the conference. QCon had a great line up and awesome keynote speakers: Turing award winner Barbara Liskov, Ward Cunningham, inventor of the Wiki, and of course Damian Conway who gave two highly entertaining keynotes. My colleague Sven Johann and I were at QCon for three days. We attended a few talks together but also went our own way from time to time. Below I discuss the talks I attended that Sven didn’t cover in his QCon blog from last week.

Ideas not art: drawing out solutions – Heather Willems

The first talk I cover has nothing to do with software technology but with communication. Heather Willems shows us the value of communicating ideas visually. She started the talk with an entertaining discussion of the benefits of drawing in knowledge work. Diagrams and visuals help us to retain information and helps group discussion. The short of it: it’s OK to doodle. In fact it is encouraged!

The second part of the talk was a mini-workshop where we learned how to create our own icons and draw faces expressing basic emotions. These icons can form the building blocks of bigger diagrams. Earlier in the day Heather made a graphic recording of Barbara Liskov’s keynote. In real-time: Heather was drawing on-the-spot based on what Barbara was talking about!

Graphic recording keynote Barbara Liskov

Graphic recording of Barbara Liskov’s keynote ‘The power of abstraction’

You are not a software developer! – Russel Miles

Thought provoking talk by Russel Miles about simplicity in problem solving. His main message: in the last decade we learned to deliver software quite well and now face a different problem: overproduction. Problems can often be solved much easier or without writing software at all. Russel argues that software developers find requirements boring, yet they have the drive to code, hence they sometimes create complex, over-engineered solutions.

He also warns of oversimplifying: a solution so simple that the value we seek is lost. His concluding remark relates to a key tenet of Agile development: delivering valuable software frequently. He proposes to instead focus on ‘delivering valuable change frequently’. Work on the change you want to accomplish rather than cranking out new features. These ideas are related to the concepts of impact mapping, which he used to structure the presentation itself, he revealed in the end 🙂

Want to see Russel live? He will be giving an updated version of this presentation at a GOTO night in Amsterdam on May 14 and he’ll be speaking at GOTO Amsterdam in June too.

The inevitability of failure – Dave Cliff

In this talk professor Dave Cliff of the Large Scale Complex IT systems group at University of Bristol warns us about the evergrowing complexity in large scale software systems. Especially automated traders in financial markets. Dave mentions recent stock market crashes as failures. These failures did not make big waves in the news, but could have had catastrophic effects if the market did not recover properly. He discusses an interesting concept, normalization of deviance.

Everytime a safety margin is crossed without problems it is likely that the safety margin will be ignored in the future. He argues that we were quite lucky with the temporary market crashes. Because of ‘normalization of defiance’ it’s only a matter of time before a serious failure occurs. Unfortunately I missed an overview of ways to prevent these kind of problems. If they can be prevented at all. A principle from cybernetics, Ashby’s law of requisite variety, says that a system can only be controlled if the controller has enough variety in it’s actions to compensate any behaviour of the system to be controlled. In a financial market, with many interacting traders, human or not, this isn’t the case.

Performance testing Java applications – Martin Thompson

Informative talk about performance testing Java applications. Starts with fundamental definitions and covers tools and approaches on how to do all sorts of performance testing. Martin proposes to use a red-green-debug-profile-refactor cycle in order to really know what is happening with your code and how it performs. Another takeway is the difference between performance testing and optimization. Yes, defer optimization until you need it. But this is not a reason not to know the boundaries of your system. When load testing, use a framework that spends little time on parsing requests and responses. All good points and I’ll have to read his slides again later for all the links to the tools he suggests for performance testing.

Insanely Better Presentations – Damian Conway

Great talk on how to give presentations. Damian shows examples of bad slides and refactors them during his talk. He discusses fear of public speaking, how to properly prepare a talk, a lot of great tips! I won’t do the talk justice by describing it in text. Many of Conway’s ideas have to be seen live to make sense. Nevertheless there is a method to the madness:

  • Dump everything you know on the subject
  • Decide on 5 main points and create storyline that flows between them
  • Toss out everything that does not fit the storyline
  • Simplicity – show less content, on more slides
  • Use highlighting for code walkthroughs
  • Use animations to show code refactorings
  • Get rid of distractions
  • The most important part of a presentation is person-to-person communication!
  • Practice in front of an audience at least 3 times. Even if it is just your cat.

Visualization with HTML 5 – Dio Synodinos

In this tour of technologies for visualizing data, Dio showed everything from CSS3 to SVG, processing and D3js. For each of these he gave a good overview of their pros and cons and made specific animations and demos for all of them. He also mentioned pure CSS3 iOS icons. Lot’s of eye candy and from reading the #QconLondon Twitter stream it seems a few people liked to try out all these frameworks and technologies.

Coffee breaks

Thankfully, there were plenty of coffee breaks at the conference. During breaks I often bumped into Sejal and Daphne, as well as other Triforkers from both our Zurich & Aarhaus offices. Besides attending talks we went to a nice conference party and went out to dinner a few times. Between talks Sven and I meetup and had a chat about what we saw, whilst we grabbed some delicious cookies here and there. Unfortunately the chocolate chip ones were gone most of the time!


At one point I took the elevator to the top floor. On my right is a large table covered with techy books. Conference goers try to walk by, but look over and can’t help but gravitate to this mountain of tech information. Of course I couldn’t resist either so I browsed a bit and finally bought ‘Team Geek – A software developer’s guide to working well with others’. Later on I visit the web development open space. I listen in on a few conversations and end up chatting with James and Kathy, the camera operators, while they are packing their stuff. They have been filming all the talks for the last three days and we talk a bit about the conference until the place closes down.

All in all QCon London 2013 was a great conference!

JTeam is hiring!

September 14th, 2010 by

JTeam is a Java software development company based in Amsterdam, The Netherlands. We do cool and innovative projects for our clients, using Agile methodologies and with a strong preference for Open Source software components. We are currently a team of 35 people, most of which are software developers, architects and consultants.

Because business is going very well, we are looking to expand our team of experts. We are looking for talented people that are looking for a place to work on challenging projects, make a name for themselves (and us), basically the best-of-the-best! If you feel you belong in this category and are looking for a new challenge, contact us at:

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