Forming, storming, norming & performing

“The Forming – Storming – Norming – Performing model of group development was first proposed by Bruce Tuckman in 1965, who maintained that these phases are all necessary and inevitable in order for the team to grow, to face up to challenges, to tackle problems, to find solutions, to plan work, and to deliver results. This model has become the basis for subsequent models of group development and team dynamics and a management theory frequently used to describe the behavior of existing teams. It has also taken a firm hold in the field of experiential education since in many outdoor education centers team building and leadership development are key goals.”

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Your favorite Webapps as easy to installable stacks


Today I stumbled upon an article mentioning the existence of BitNami. It was an unknown product to me, but I think it has some potential. Imagine the power of Lampp combined with your favorite cms/wiki/…

The key features where they prize themselves with:

  • Easy to install
    In just a few clicks, you can have your favorite open source applications up and running.
  • Multiplatform
    Bitnami Stacks are available for Linux, Windows, and Mac OS X.
  • Integrated
    By the time you click ‘finish’, the software will be integrated, configured and ready to go.
  • Independent
    Bitnami Stacks won’t interfere with any software already installed on your system.
  • Run Natively
    The stacks install directly on your system – no virtual machine required.
  • Open Source
    All Bitnami Stacks are free to download and use under the terms of the Apache License 2.0

For a full list, check out the their stacks page.

Monitoring your LTM/BIGIP through Cacti

PrefaceCacti F5 LTM Screenshot
Capturing load balancer traffic flows is not something that is elegantly handled by most commercial applications. Several can’t even gather statistics on the F5 appliances because they lack the ability to index mibs. With the help of some excellent templates found on the Cacti forums, you will be able to successfully graph my virtual servers, interfaces, and memory. This article will walk you through the steps required to install & configure Cacti to begin monitoring the F5 LTM Global Traffic, Virtual Server Traffic, Interface Traffic & Memory.

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MySQL to be acquired by Sun

The speculations

  • Integration with Java : At the moment Oracle is seen as the “prefered database partner” for J2EE applications. This might be the start of a business move to get MySQL into this position.
  • Marketing / Image : MySQL is a popular database, and has it’s respect within the OSS community, so it’s a good for the PR. (Yet expensive if that would be the only side…)
  • Wide support : Whilst SUN was already working with PostgreSQL, this might allow them to give their customers the choice between three database systems (Oracle, PostgreSQL & Mysql) with their products.
  • Competititors : Will RedHat & IBM focus on getting PostgreSQL in the lift? In order to put (financial) weight into the alternative…
  • Engine collisions : Given that it would be a vendor showdown, how will it turn out of MySQL as their best enginers (InnoDB & BerkeleyDB) are owned by Oracle?

Official Statement
Kay Arno’s blog
Jonathan Schwartz’s blog
Jignesh K. Shah’s blog

The Quotes
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The basics behind the Completely Fair Scheduler

The GNU/Linux kernel, version 2.6.23, comes with a modular scheduler core and a Completely Fair Scheduler (CFS), which is implemented as a scheduling module. If you’re interested in the workings of this scheduler, be sure to check out the following article at DevWorks. Below you can find an excerpt of the article, which is in my opinion the core of the article.

How CFS worksSchedule
The CFS scheduler uses an appeasement policy that guarantees fairness. As a task gets into the runqueue, the current time is recorded, and while the process waits for the CPU, its wait_runtime value gets incremented by an amount depending on the number of processes currently in the runqueue. The priority values of different tasks are also considered while doing these calculations. When this task gets scheduled to the CPU, its wait_runtime value starts decrementing and as this value falls to such a level that other tasks become the new left-most task of the red-black tree and the current one gets preempted. This way CFS tries for the ideal situation where wait_runtime is zero!

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Nine Characteristics of Free Software Users

The “9 Characteristics of Free Software Users” (by Bruce Byfield) is an interesting read about his view on the nine characteristics of Free Software Users:

Free software users :

  • expect open licenses and no activation methods
  • expect regular upgrades and patches
  • expect to work the way they choose
  • want control of their own systems
  • explore
  • expect to help themselves
  • don’t fear the command line
  • learn software categories, not programs
  • expect access to developers and other employees

His ConclusionFree Software
How long these characteristics of free software will continue to exist is uncertain. In the last few years, a new category of free operating system users has begun to emerge: those who remain entirely on the desktop. In the rush to become more user-friendly — which usually means more like Windows — the chance exists that the free software user culture will become unrecognizable to long-time users in the next few years.

However, that seems unlikely. For the most part, the purely desktop user’s sensibilities are not sapping the free software culture so much as being accommodated and isolated as a special case. Unless they are content to stay in their normal routines, within a year or two, desktop users will face some problem that they cannot solve without becoming either more adventurous or more in contact with the mainstream culture. When that happens, they will have taken the first steps away from being passive consumers and towards becoming the owners of their own machines.

OWA Most Popular – version 1.2

OWA Most Popular has been updated.


Seperate function
It is possible to call the function directly in your php code (hint: templates), by using the following function:


New algorithm
The widget will use weighted algorithm, if you would set the variable $style_owa_popular to “weighted”. The formula is pretty simple, being:

(Sort) Factor = number of visits / (date difference (in days) + 1)

Important note : This weighted algorithm is pretty (system) resource intensive, I would advise you to use some form of caching mechanism in combination with this option.

How does an email get delivered?

The basics
When asked for which purposes people most frequently use their computer, then the response often contains the term “email”. Yet in my experience most people have no clue how this digital letter gets from person X to person Y. This article will sketch a rough image of how email works.

Email Person X types an email in his/her mail client (to for example This can either be a web based or locally installed client. After pressing the “send” button, the email will be sent towards an outgoing mail server (MTA). This server will queue the mail, and lookup the location where this mail should be delivered by using a DNS server. Imagine the DNS server as a catalog of the internet. It contains (or can lookup) the network locations of a certain domain name (like The MTA will ask the DNS server to give the location of the mail server (mx record) for

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UK next in line to ban hacking tools

The UK government has published guidelines for the application of a law that makes it illegal to create or distribute so-called “hacking tools”. Germany has preceded the UK in these steps, causing security researchers to challenge this law.

So how far would the definition of “hacking tools” go?
nmap matrix

  • Nmap – Okay, it’s a scanning tool, but I often use it for my profession too… Same goes for WireShark.
  • IDE – An ide can be used to code malicous programs, are those going to be banned too?
  • OS – Why not ban linux or windows? Windows because it’s the most popular system to be compromised, and linux because we can’t trust those people offcourse! 😉
  • To me this is once again a situation where goverments fail to provide decent measures to cover a certain objective. It’s even a case of shooting yourself in the foot. Why block your researches from having certain tools to block the “bad guys”? Where these attacks are often foreignly based. A more interesting attempt would have been to try to setup an international code/organisation that would make it more easy to find & prosecute these violators.