"Firefox is already running problem" on Linux

I am an avid fan of Linux and use it at home, on my office desktop as well as my laptop. Also firefox seems to be the best browser available on the Linux platform. However sometimes it quite happens that firefox crashes and restarting it can be really very nasty. Quite often you see a message saying that there is already an instance of firefox running. The way to overcome this problem is to go to the .mozilla/firefox subdirectory under your home directory. After this, go to the subdirectory which has an extension .default. This basically contains all the bookmarks and other customizations like plug-ins etc that you have added for your firefox browser. Now do a "ls -la | grep lock" in this directory and then delete the files that correspond to this output. These basically correspond to the lock(s) that did not get deleted when the browser crashed. Now restart the browswer, it should start without a problem.

Google's PageRank explained using Markov Model

This page has an awesome explaination of the Google's pagerank algorithm using Markov modeling.

Speed does matter....especially in case of Computers

My thesis topic at Clemson subsumed "Peformance Analysis Framework for Coven". In simple words I had developed a software framework to understand (visualize) the performance of parallel programs running on Beowulf clusters. These programs were written using a component based language called Coven which was developed at the PARL lab in Clemson. Fortunately after school I got a job as Performance Engineer at NetApp and I am basically involved in engineering projects that improve the performance of the storage appliance we develop. This implies working and analyzing lots of data using Microsoft Excel as well as GNUplot and then making the required changes to our OS and file system.

The current project that I am working on involves lots of analysis work instead of programming and I am really loving it. However I have realized that I lack the knowledge of advanced mathematical tools which would give me a deeper understanding of what is going on. Hence I plan to study the following concepts in the coming few days

1) Fundamentals of Probability (Just a quick brush up)
2) Markov chains (Had learnt this but have completely forgotten)
3) Queuing concepts (M/M/1 etc)

Hopefully will be fun. Also to make this learning interesting I plan to write some scripts that will make use of this newly acquired knowledge.

Using SSH instead of telnet

In my last article I explained how to enable port forwarding for telnet on the Netgear router. However performing port forwarding for ssh is trivial as well and at the same time much secure. I am assuming that your home Linux box is running the sshd service.

Now on the router side go to the Netgear administrator page and then browse to "Advanced -> Port Forwarding". Click "Add Custom Service" and enter values shown below.



You can now log into your Linux box by sshing to the static IP assigned to your router.

Home server on the internet

PLEASE NOTE IT IS EXTREMELY DANGEROUS TO HAVE YOUR HOME MACHINE CONNECTED AS A SERVER OVER THE INTERNET

Today I am going to explain how to connect a Linux box on a home network to the internet. I had to do this because I wanted to access my home Linux box from my office.

I have a x86 box running Fedora Core 5. This box is connected to a Netgear Router (MR814v2) directly via ethernet. The local IP address of this box on the network is 192.168.0.3 . In order to get this box accessible from the office, I first installed a telnet-server on the machine. Once the telnet daemon was installed I then started the telnet service using the command /etc/init.d/xinetd start.

The next step involved configuring the router. You need to log into the router by typing http://192.168.0.1 and then entering your administrator login and password. After this go to the Advanced -> Port Forwarding and select the telnet service and the IP address of the Linux box, in my case 192.168.0.3 and click add. This instructs the router to forward an telnet sessions to the Linux box.

Finally inorder to connect to the Linux box you need to telnet to the static IP assigned to your router and that's it. Your machine is now accessible anywhere from the world over the internet but at the same time it is very much prone to online attacks. I recommend using SSH instead of telnet however Netgear does not seem to support port forwarding for SSH. Need to dig further to be more secure.

Long weekend

Had been to outerbanks for the long weekend along with Bully and Bonda. Was lots of fun