Scrum Tisch

2009-06-04 11:27
Title: Scrum Tisch
Location: Divino FHain
Link out: Click here
Description: Philippe will present his speech from the Orlando scrum Gathering where he will speak about backlog and time-box, about value versus cost, about visible features versus invisible features (and in particular software architecture), about defects and technical debt, and more generally about release planning and sprint planning for non-trivial and long-lived software development projects.
Start Time: 18:00
Date: 2009-06-16

Scrum Tisch

2009-06-04 11:27
Title: Scrum Tisch
Location: Divino FHain
Link out: Click here
Description: Philippe will present his speech from the Orlando scrum Gathering where he will speak about backlog and time-box, about value versus cost, about visible features versus invisible features (and in particular software architecture), about defects and technical debt, and more generally about release planning and sprint planning for non-trivial and long-lived software development projects.
Start Time: 18:00
Date: 2009-06-16

Ken Schwaber in Berlin XBerg

2009-05-24 18:56
Last week I attended a discussion meetup with Ken Schwaber in Berlin/ Kreuzberg. The event was scheduled pretty shortly - still quite a few developers and project managers from various companies in Berlin showed up.

Ken started with a brief summary of the history of Scrum: Before there was such a thing as an IT industry programming actually was a lot of fun. But somehow the creative job was turned into something people tend to suffer from pretty quickly as people tried to apply principles from manufacturing industries to software "production". Suddenly there was a distinction between testers, programmers, architects... People tried to plan ahead for months or even years noticing only very late in the process that the outcome was by no means what was needed when the product finally was ready.

In contrast to waterfall Scrum comes with very short feedback loops. It comes with developers working with very strong focus on one task at a time. Change is not hated but embraced and built into development.

Some features of Scrum that are often forgotten but never the less essential that were discussed that evening:


  • Scrum is all about transparency - it's about telling your customers what is going on. It is about telling your customer honest estimations. It is about telling development to the best of your knowledge all that can makes up for a feature.
  • Scrum is neither easy nor a solution in itself. It is simply a way of uncovering problems very quickly that are easier to hide in waterfall processes. You have one person who is an isle of knowledge in your company? At every sprint planning this problem will become obvious until you find a way to solve it.
  • Scrum is about giving developers a box of time that is not to be interrupted. Developing software asks for a lot of concentration. Getting interrupted and resuming work on the task again is so expensive that there is close to nothing this can be justified with.
  • A nice way of doing Scrum is to use Scrum for management and XP for development. Scrum does not provide any solutions on how to reach the goals set - it does not tell you exactly how to arrive at a stable release by the end of your sprint. It just sets the goal for you. On the other hand XP holds quite a few development best practices that can help achieve these goals.
  • It needs time to change how customers and developers are working: Yearlong experience has trained them to think in certain ways. So at the beginning Scrum is all about teaching and training people. It takes time to learn a new way of getting things done.


There are ways to do fixed price contracts with Scrum. You just have a few more freedoms to offer to your customer:


  • Tell your customer that your clients usually change their mind underway. Give them the freedom to change anything not yet implemented. An item can be exchanged with an item of equal cost for no increase in prize. An item can be exchanged with a cheaper item with a decrease of cost, it can be exchanged with a more expensive item for a rise in cost.
  • Tell your customer that you already have pre-priorized items. The client is free to re-prioritize items as he wishes - as long as the item was not implemented already.
  • Tell you customer that as you are implementing those items at first that have a high priority you may come to a point where those items not done are not important for release so he could eventually stop early and pay less.


In summary the evening was very interesting and insightful for me. It helps to talk about Scrum implementation problems. To learn which problems others have and how they attack these problems.

Open Source Development is good for you

2009-05-21 09:08
GSoC (Google summer of code) - one of the open source programs of Google - has started again in 2009. Students come to work for open source projects during the summer and on success are paid by Google a fair amount of money.

This program is an ideal oportunity for students to get into open source projects: You get a mentor, you have pre-defined task to work on with a goal you set yourself. And in the end there is money.

At the beginning of GSoC student ranking Ted Dunning posted a very interesting mail on his view on why students should participate in open source development:

  • It is a perfect chance to work together with senior developers that are passionate about what they do.
  • Usually universities teach the theoretical side of life, which is good. But if working in industry later, students need experience with current development best practices and tools. They need to be aware of test driven development, they need to know how to use source control systems, continuous integration tools, build management frameworks, bug tracking tools. Open source projects usually are a great place to try out these technologies and learn how to best apply them.
  • Working on open source students need to coordinate with their peers. They need to learn that development is not only about coding, but about communication as well.
  • Last but not least this is a chance to chose yourself what you are working on and achieve so much more than when starting yet another brand new single developer project.


In the end all this adds up to learning and practicing the skills needed to successfully work on software development projects with more than just a few developers.

Tomcat Tuesday talk

2009-05-21 09:07
Since several months at neofonie we have a talk given by external or internal developers on various subjects each Tuesday. Usually these presentations are a nice way to get an overview of new emerging technologies, to get an overview of current conference topics or to gain insight into interesting internal projects.

This week we had Apache Tomcat Committer and PMC Peter Rossbach here at neofonie to talk about the Tomcat architecture and Tomcat clustering solutions. He gave two pretty in-depth presentations on the Tomcat internals, Tomcat optimization and extension points.

Some points that were especially interesting to me: The project started out in the late nineties, initiated by a bunch of developers who just wanted to see what it takes to write a web application container and that fullfills the spec. The goal basically was a reference implementation. Soon enough however users defined the resulting code as production ready and used it.

There are a few caveats from this history that are still visible. One is the lack of tests in the codebase. Sure, each release is tested agains the Sun TCK - but these tests cannot be opened to the general public. So if you as a developer make extensions or modifications to the code base there is no easy way of knowing whether you broke something or not.

For me as a developer it was interesting to see really how complex it quickly gets to cluster tomcat deployments and make them failure resistant. Some tools mentioned that help automatic with easier deployment are Puppet and FAI. One issue however that is still on the developer's agenda is Tomcat monitoring.

To summarize: The conference room was packed with developers expecting two very interesting talks. Thanks to Peter Rossbach for coming to neofonie and explaining more on the internals of the Tomcat software, the project and the community behind.

Back from Zürich

2009-05-05 16:58
I spend the last five days in Zurich. I wanted to visit the city again - and still owed one of my friends there a visit. I am really happy the weather was quite nice over the weekend. That way I could spend quite some time in town (got another one of those puzzles) and go for a hike on the Ütli mountain: I took the steep way up that had quite a lot of stairs. Interestingly though, despite being quite tired when I finally arrived on top, my legs did not have sore muscles the next day. Seems going to work and back again by bike does indeed help a bit, even if we have no hills in Berlin.

Yesterday I was allowed to present the Apache project Mahout in a Google tech talk. Usually I am talking to people well familiar with the various Apache projects. Giving my talk I asked people who was familiar with Lucene, with Hadoop. To me it was pretty unusual that very few engineers were aware of these. It almost seemed like it is unusual to have a look at what is going outside the company? Or was it just the selection of people that were interested in my talk?

I tried to cover most of the basics, put Mahout into the context of the Lucene umbrella project. I tried to show some of the applications that can be built with Mahout and detailed some of the things that are on our agenda.

Some of the questions I received were on the scalability of Hadoop, on the general distribution of people being paid to work on Free Software projects vs. those working on them in their freetime. Another question was whether the project is targeted to text only applications (which of course it is not, as feature extraction so far has been left to the user). Last but not least the relation to UIMA was brought up by a former IBM-UIMA engineer.

To summarize: For me it was a pretty interesting experience to give this tech talk. I hope it did help me to do away with some of my "Apache bias". It is always valuable to look into what is going outside one's community.

DIMA @ TU Berlin

2009-05-03 07:26
On Friday, the 24th of April Prof. Volker Markl organised a Welcome Workshop at TU Berlin. The day started with an introduction by the Dekan of the faculty. First talk was given by Rudolf Bayer on the topic "From B-Trees to UB-Trees". Second presentation was by Guy Lohman on "LEO, DB2's Learning Optimizer".

After the coffee break, Volker Markl gave an introduction to his selected research field, outstanding tasks and the way he is going to accomplish his goals. Seems like scalability is playing a major role in his tasks. Interestingly Hadoop was chosen as an infrastructure basis.

In his talk Volker Markl announced the newly started BBI Colloquium. It is a regular meeting in Berlin dedicated to the scientific discurs on topics relevant to the participating researchers. Participating researchers are Prof. Oliver Günther, Prof. Johann-Christoph Freytag, Prof. Ulf Leser from HU Berlin, Prof. Dr. Volker Markl from TU Berlin, Prof. Dr. Heinz Schweppe from FU Berlin and Prof. Dr. Felix Naumann from HPI Potsdam.

Scrum Table with Thoralf Klatt

2009-04-29 09:19
On Wednesday, the 22nd of April, about 20 people interested in Scrum gathered in the DiVino in Friedrichshain/Berlin. The event was split in two parts: In the first half we gathered topics participants were interested in, put priorities next the them and discussed the most highly ranked topic: "Scrum in large teams, splitting large tasks across teams."

The basic take home messages of the discussion:
  • One way to cleanly split a task across teams is to first do a design sprint together, fix the API and then split up. Problem with that: Integration and validation of what you do theoretically up front.

  • Another way is to continously integrate all parts, that way you get direct feedback. Might be impractical without a sort of fixed API though.

  • Do keep in mind that increasing the team exponentially increases management overhead.

  • Do track the progress and performance with well known values (delivered value per sprint, velocity, define KPIs etc.)



The second part of the meetup was covered by the talf of Thoralf from Nokia Siemens networks on how they do scrum across countries and continents. Main interessting points for me:
  • Face to face communication is necessary - good video equipment can help with that.
  • Integrating ready made products into new solutions create new challenges to solve.
  • Transparency and communication with developers become a challenge.


More information on the event can be found on the blog of the round table.

Feedback from the Hadoop User Group UK

2009-04-29 08:54
A few weeks after the Hadoop User Group UK is over, there are quite a few postings on the event online. I will try to keep this page updated if there are any further reviews. The one I found so far:

http://huguk.org/2009/04/huguk-2-wrap-up.html - the wrap-up of the event itself.

http://blog.oskarsson.nu/2009_04_01_archive.html - a short summary by the organiser - Thanks again for a great event.

http://www.cloudera.com/blog/2009/04/21/hadoop-uk-user-group-meeting/ - a short summary on the Cloudera blog.

http://people.kmi.open.ac.uk/adam/?p=26 - a quick overview with a Mahout focus by Adam Rae.

June 2009 Apache Hadoop Get Together @ Berlin

2009-04-23 19:30
Title: Apache Hadoop Get Together @ Berlin
Location: newthinking store Berlin Mitte
Link out: Click here
Description: I just announced the fifth Apache Hadoop Get Together in Berlin at the newthinking store. Torsten Curdt offered to give a talk on data serialization with Thrift and Protocol Buffers.

If you have a topic you would like to talk about: Feel free to just bring your slides - there will be a beamer and lots of people interested in scalable information retrieval.
Start Time: 17:00
Date: 2009-06-25