Host Networking with VirtualBox 2.1

Finally. The new version of Sun’s VirtualBox makes the fiddling with tunnels obsolete. It basically works the same way as in VMware now.

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New release of Java 1.5

Sun released Java 1.5.0_17 today. This release fixes (among other things) the regression bug of Java 1.5.0_16 which made it impossible to view and edit metadata in Conzilla. I wrote about this in a previous blog post.

Generally I recommend to use Java 1.6, but if you have to use 1.5 for some reason you can get the new version directly from Sun.

Sun xVM Host Interface Networking on Ubuntu

I just struggled a bit with getting xVM’s host interface networking up and running on Ubuntu. It works now and maybe somebody else finds the following short how to useful.

Host Setup

Run “sudo aptitude install bridge-utils”.

Add the following lines to /etc/network/interfaces:

auto tap0
iface tap0 inet manual
  tunctl_user user # replace "user" with the user name running xVM
  uml_proxy_arp sativex-ub

auto br0
iface br0 inet static
  address 10.10.1.1
  netmask 255.255.255.0
  bridge_ports tap0
  bridge_maxwait 0

Run “service networking restart”. (or “/etc/init.d/networking restart” if your Ubuntu doesn’t have the service command yet)

Run “sudo VBoxAddIF vbox0 user br0”. (like above, change “user” to your xVM user)

In your VM settings choose “Attached to: Host Interface”, as “Interface Name” in the field below enter “vbox0”. If you want to have Internet access in your VM you should also configure a second network interface, pick “Attached to: NAT” there.

VM Setup

Start up your VM, and add the following lines to /etc/network/interfaces:

auto eth0
iface eth0 inet static
  address 10.10.1.2
  netmask 255.255.255.0

auto eth1
iface eth1 inet dhcp

Run “service networking restart”.

That’s it, your VM should now be accessible (from your host) via 10.10.1.2. Of course you can adjust the IP addresses/networks as you like.

WOD-PD 2008 | Web of Data Practitioners Days

On Wednesday and Thursday I attended the Web of Data Practitioners Days (WOD-PD 2008) at “Altes AKH” in Vienna. AFAIK it was the first event of such a kind, it was something in between academic presentations and hands-on sessions, everything about Semantic Web and its related technologies.

I liked this format of a workshop very much, especially the “hacking session” in the evening of the first day with its “lightning talks”, and of course the socializing in between the talks. I finally had the chance to talk to some guys I already knew from various blogs and publications, but never have met in real life.

The Semantic Web Company (an austrian company who is pushing the Semantic Web topic really hard forward) was represented by Jana Herwig and published a few blog posts summarizing the talks of the event:

The proceedings are online with almost all presentations and links to the web sites which were used for the hands-on sessions.

Oh yes, of course there are pictures online on Flickr tagged with wodpd2008.

Recent problems with launching Conzilla

I got several emails these days from people who were not able to launch Conzilla anymore. The reason was an exception (“java.net.MalformedURLException: no !/ in spec”) during start up.

I investigated the problem (which is caused by a regression bug of Sun’s most recent Java 5.0, i.e. 1.5.0_16) and tried to work around it, but came to the conclusion – as many other developers who tried to solve the very same problem – that it is best to wait for a fix from Sun.

The reason is that it would require too many changes in the code and even some major refactoring. Apart from that, even third-party libraries as e.g. log4j are affected. Conzilla is not the only application which has been broken, basically all applications making use of Java Web Start are affected.

Bugs have been reported to Sun:

http://bugs.sun.com/view_bug.do?bug_id=6746185
http://bugs.sun.com/view_bug.do?bug_id=6753651

Let’s hope that Sun fixes this bug very soon, until then my recommendation is: Do not use JRE/JDK 1.5.0_16, and if you happen to use it, downgrade to an earlier release, or upgrade to 6.0/1.6.

I will keep you informed regarding this issue.

Sarek at Wild Wonders of Europe

The photographer Peter Cairns writes about his experiences in Sarek at Wild Wonders of Europe.

He obviously experienced the same phenomenon as I did, as he writes

To be honest, it was one of those places that to the eye, looked fantastic but that never quite translated into images.

and

Sarek was nothing short of an adventure: a roller coaster of fortunes and emotions and an experience that I’ll never forget. In many ways, trying to convey the majesty of such a place in photographs is fruitless and an insult to Sarek’s ecological complexity.

I could not agree more. It is highly unsatisfactory to show own pictures or to describe Sarek in words. I’m just lacking appropriate descriptive vocabulary (even in my mother tongue) in order to impart my impressions.

Experience Sarek yourself and you will see what I am talking about.