Tuesday, July 17, 2012

RoboCanes place 2nd in international robot soccer competition

The College of Arts and Sciences' Department of Computer Science RoboCanes team placed second in 3D soccer simulation at the 2012 RoboCup last week in Mexico City. Read more ... 

Saminda Abeyruwan, Justin Stoecker, Andreas Seekircher, and Professor Ubbo Visser accept their tropy at the RoboCup in Mexico City.

Thursday, August 11, 2011

Java 7 with JSR 334

JDK 7 with JSR 334 (Small language enhancements). I think that the the strings in switch, and multi-cache and more precise rethrow is quite useful.

Friday, December 25, 2009

Wolfram Alpha - Computational knowledge engine

Wolfram Alpha is an answer engine which provides ANSWERS to structured queries (e.g captial of sri lanka), rather providing a ranked list of web pages that most popular search engines would do. This engine uses automated reasoning to infer other results which is most useful for users. Thought the inferences that the engine makes is not currently amenable for my knownledge as of this writing, it gives very useful inferences. For more information read this and this.

Note:
I explicitly made the error in search query; "captial of sri lanka" (captial rather capital) to show how inferencing is done on the context of the search query.

Thursday, September 10, 2009

Gtk-WARNING **: cannot open display

When you ssh to a remote machine and want to execute a graphic bound applications such as JFrame etc, use ssh with -X argument. -X is for forwarding.

ssh -X user@host

Sunday, August 30, 2009

How to install kernel headers to build modules against the Xen kernel - Amazon EC2

If you are using a Ubuntu/Debian AMI, and need to install kernel headers to build modules: apt-get would not work almost all of the time. You would probably end up with doing something like following,
root@domU-XX-XX-XX-XX-XX-E1:~$ apt-get install linux-headers-`uname -r`
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Couldn't find package linux-headers-2.6.21.7-2.fc8xen
root@domU-XX-XX-XX-XX-XX-E1:~$
I used the following method to get Kernel headers and compile a VMWare 2 instance. This method will always work,
wget http://kojipkgs.fedoraproject.org/packages/kernel-xen-2.6/2.6.21.7/2.fc8/i686/kernel-xen-devel-2.6.21.7-2.fc8.i686.rpm
alien -k --scripts kernel-xen-devel-2.6.21.7-2.fc8.i686.rpm
dpkg -i kernel-xen-devel_2.6.21.7-2.fc8_i386.deb
ln -s /usr/src/kernels/2.6.21.7-2.fc8-xen-i686 /lib/modules/
2.6.21.7-2.fc8xen/build
ln -s /usr/src/kernels/2.6.21.7-2.fc8-xen-i686 /usr/src/linux
Make sure to include symbolic links to .configure to work properly.

Thursday, August 27, 2009

Virtual cloud? or something like that

Everyone on the plant is really interested in cloud computing these days. There are many organizations specialized in providing HaaS services. Is it possible for someone to build their own cloud, if one could find a hardware rich machine. Yes!, it is. Lets call this is a virtual cloud. How can a virtual cloud is built?. Simple, use VMWare 2. Let see what I did,

1. I have two machines. A hardware rich machine A (172.19.0.32) and some other machine B (172.19.0.44).

2. I downloaded and installed VMWare 2 in machine A. This version is free and you will get an access key free too. Follow the simple instructions to install VMWare 2. VMWare 2 has a very powerful web console. Default http port is 8222 and https port is 8333. To install VMWare 2 in Ubuntu, follow these instructions.

3. Now I am going to create an VMWare image to install Ubuntu 9.04. Ubuntu is my all time favourite Linux distribution.

4. From machine A, open up a Mozilla browser and type http://172.19.0.32:8222. Login using "root" and the password. Create the VMImage for Ubuntu 9.04. If you are using the "console" tab for the very first time, browse will ask to download VMWare Remote Console Puglin. Download and restart the browser.


5. Create many number of VMImages. Use different distributions. If you want you can use Windows too. Logout after this.

This is the place where we can introduce the notion of a virtual cloud. Each VMImage can be treated as a node in a cloud. There is one limitation though. This cloud can grow up until it runs out of VMImages.

6. I have created my virtual cloud in the previous step. How can I access it from out side. Lets go to machine B. In my example machine B is in the same network. Access the VMWare 2 using http://172.19.0.44:8222. Login as "root" and password. I need to find out administration permissions documents to create users to access VMImages but "root".



7. In this example, there is only one VMImage. Select it and power it up. You can turn on many VMImages.




This way you can create your own private virtual cloud.

Amazon EC2 allows users to create custom AMIs. Unless one does not have an agreement with them, one can not build AKIs and ARIs. If I do the prior in an Amazon EC2 node, I would definitely be able to run a distribution with my kernel, without worrying about underlying necessaties. This process might be possible to try in any cloud service providers.

One would ask, why would you want to do this after all. Well I am a grad student and this is fun!.