Showing posts with label Fedora. Show all posts
Showing posts with label Fedora. Show all posts

Communicating over SCTP in Java

  • Posted by Chathurika Sandarenu
  • Friday, May 01, 2009

SCTP - Stream Control Transmission Protocol is a relatively new (standardize in year 200 by IETF) transport layer protocol to design to operate over IP. It is an alternative for TCP and UDP and combines many good features of those protocols. Main intention of developing SCTP was to cater the growing demand of IP telephony market. 

Since SCTP is relatively new protocol programming language support for this is also not as commonly available as TCP or UDP, especially you are Java developer. But is you are a C/C++ developer then you have no problem, there is a very good guide on UNIX - Network Programing Vol1-3rd Edition (chapter 9, 10 and 23).

If you are Java developer then you'd have to use OpenJDK instead of Sun java JDK, since at present only OpenJDK has the support for SCTP. So first thing you have do is to download and install OpenJDK-7.  Currently it only has versions for Linux and Solaris, again if you are using Windows then you'll have to do some more research. I've tried this only on Linux(Fedora), may be later I'll try with Windows as well. If your Linux kernel do not support SCTP, then you'll have install LKSCTP as well. Here is the small getting started guide at OpenJDK site. You can use the small test program given that guide to test whether your SCTP stack if working properly. I'll post small client-server program in SCTP in a later post.

PS: I found this SCTP library for Windows http://www.sctp.be/sctplib/, but couldn't check whether there is a support from OpenJDK-SCTP side for windows. If you find something please let me know as well.

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Extending Nautilus with Scripts

  • Posted by Chathurika Sandarenu
  • Wednesday, November 12, 2008
Nautilus is the default file browser we get with Gnome. Today I found out about wonderful feature of it. We can very easily extend Nautilus functionalities by adding our own custom scripts.  These scripts can be any executable file like shell script, python script or even C/C++ program.  You only have copy your scripts to
~/.gnome2/nautilus-scripts
We can get information such as current directory path, selected files using environmental variables set by Nautilus. Full set of variables are as follows.
  • NAUTILUS_SCRIPT_SELECTED_FILE_PATHS -lists the paths of the currently selected files, separated by newlines. Works only on local filesystem.
  • NAUTILUS_SCRIPT_SELECTED_URIS - contains the URIs (file://file) of the selected files, separated by newlines. Works on both local and remote filesystems.
  • NAUTILUS_SCRIPT_CURRENT_URI - contains the URI of the current directory. Works for both local and remote filesystems.
  • NAUTILUS_SCRIPT_WINDOW_GEOMETRY -provides the window location and geometry of the browser window.
Nautilus also passes list of selected files as args to your script.  So we can use them to do what ever processing we want to do.

This is a simple script that will prompt all selected files in a message box.

#!/bin/bash
#Author: M.A.C.Sandarenu http://sandarenu.blogspot.com
for arg
do
fileList="${fileList}${arg}, "
done
zenity --info  --text="You have selected following file(s) ""$fileList"
 

CrossOver Rocks.....

  • Posted by Chathurika Sandarenu
  • Sunday, November 02, 2008
I managed to grab a copy of CodeWeaver's CossOver software using their 28th October promotion campaign. For those who don't know about CodeWeaver, they are the people behind the FOSS project wine which enables users to run windows applicaiton on their Linux boxes. CrossOver is commercial counterpart of the wine. The gave away $70 worth CrossOver Professional version for free on 28 Oct as a pomotion.

I Installed Microsoft Office 2007 on my Fedora 9 box using CrossOver and it works fine. I managed to install Word, Excel and Powepoint, but had problems with installing Visio.

Unfortunately CodeWeaver's aren't going to do this kind of promotions in near future. So you'll have to use Wine if you didn't managed to grab a copy on 28th Oct.










 

Firefox on Fedora - No sound on Flash Videos

  • Posted by Chathurika Sandarenu
  • Thursday, August 14, 2008
I recently shifted to Fedora from Windows XP. In Fedora it did not give sounds when I was watching flash videos such as from YouTube in Firefox. It was a big problem for me. But after some research I found out that it is due to not installing a dependency library 'libflashsupport' with Adobe Flash plugin. Fixing this problem is very simple, just insall that library using yum.

yum install libflashsupport

After intalling it I got the sounds. :)
 

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