Linux Blog

Optimize DNS lookup time using NameBench

When you use the Web or send an e-mail message, you use a domain name to do it. For example, the URL "http://linuxpoison.blogspot.com/" contains the domain name blogspot.com.

Human-readable names like "linuxpoison.blogspot.com" are easy for people to remember, but they don't do machines any good. All of the machines use names called IP addresses to refer to one another. For example, the machine that humans refer to as "linuxpoison.blogspot.com" has the IP address 209.85.153.191. Every time you use a domain name, you use the Internet's domain name servers (DNS) to translate the human-readable domain name into the machine-readable IP address. Speeding up DNS lookups is one of the simplest, and most effective ways to speed up browsing.

Namebench. hunts down the fastest DNS servers available for your computer to use. namebench runs a fair and thorough benchmark using your web browser history, tcpdump output, or standardized datasets in order to provide an individualized recommendation. namebench is completely free and does not modify your system in any way. This project began as a 20% project at Google.

namebench runs on Mac OS X, Windows, and UNIX, and is available with a graphical user interface as well as a command-line interface.

Installation:
Download NameBench from here
Go to terminal (root) and type following command to install and run NameBench:

tar -zxvf namebench-1.0.5.tgz
cd namebench-1.0.5/
python setup.py install

./namebench.py

namebench will test the nameservers your machine is currently using, plus the popular global DNS services, and the best 4-6 additional name servers that it can find for you. It will output some text-graphs and URL's for more a more detailed performance analysis of each nameserver.

If you want to specify an additional set of name services, simply add the IP to the command-line, or edit namebench.cfg:

./namebench.py 10.0.0.1 192.168.0.1

Here are my DNS server test results:

Multiget - Multi-Threaded Graphical Download Manager for Ubuntu / Debian / OpenSuSe Linux

MultiGet is an easy-to-use GUI file downloader for Windows/Linux/BSDs/MacOs. It's programmed in C++ and has a GUI based on wxWidgets. It supports HTTP/FTP protocols which covers the requirements of most users. It supports multi-task with multi-thread on multi-server. It supports resuming downloads if the Web server supports it, and if you like, you can reconfig the thread number without stopping the current task. It's also support SOCKS 4,4a,5 proxy, ftp proxy, http proxy.

Installation:
Ubuntu: $ sudo apt-get install multiget
OpenSuSe user can use "1-click" installer to install MultiGet - here
You can start MultiGet in Ubuntu by going to Applications > Internet > MultiGet

Once installed, Multiget monitors your clipboard for download links -- or you can start putting the app to use via its floating drop box. Find something you want to download in your favorite browser, then click and drag a link onto the box to initiate the transfer. Downloads can also be started via Multiget's task menu.

Handbrake - Multiplatform, Multithreaded DVD to MPEG-4 Converter & Transcoder

HandBrake is an open-source, GPL-licensed, multiplatform, multithreaded DVD to MPEG-4 converter. This software application therefore lets you compress DVDs so that they take less space on a hard disk.

HandBrake is a console (command-line interface) & GUI based tool. The application requires many switches and variables to begin the conversion of a DVD to an MPEG video file.

Features include:
Supported sources:
Any DVD-like source: VIDEO_TS folder, DVD image or real DVD (encrypted or unencrypted, but protection methods other than CSS are not supported and must be handled externally with third-party software), and some .VOB and .TS files PAL or NTSC AC-3, DTS, LPCM or MPEG audio tracks

Outputs:
File format: MP4, MKV, AVI or OGM
Video: MPEG-4 or H.264 (1 or 2 passes or constant quantizer/rate encoding)
Audio: AAC, MP3, Vorbis or AC-3 pass-through (supports encoding of several audio tracks)

Misc features:
Chapter selection
Basic subtitle support (burned into the picture)
Integrated bitrate calculator
Picture deinterlacing, cropping and scaling
Grayscale encoding

Installing HandBrake
It is extremely easy to install HandBrake on Ubuntu 9.10 , HandBrake provides easily installable .deb file for Ubuntu 8.10. To install HandBrake issue the following command in the terminal window (Application >> Accessories >> Terminal)

wget http://handbrake.fr/rotation.php?file=HandBrake-0.9.4-Ubuntu_GUI_i686.deb
sudo dpkg -i HandBrake-0.9.4-Ubuntu_GUI_i686.deb

This should install HandBrake onto your system , you can launch HandBrake from (Applications >> Sound Video >> HandBrake ).

OpenSuSe user can use "1-click" installer to install Handbrake - here

Using Handbrake
The first time you launch Handbrake you should see a number of predefined presets on right hand side of the Window , allowing you to easily configure Handbrake to convert videos to format capable of being played on number of devices.

Once you have selected the device you want to convert video for, configure/tweak the settings further and select source to select the source video which you would like to convert to suitable format, Also select the destination where you would like to save the video. Now , press Start button to start encoding the video.

How to do CPU hotplug in Linux

WHY DO WE NEED HOTPLUG CPU?

As Linux becomes more prominent in the enterprise arena in mission critical data center type installations, features that support RAS (Reliability, Availability and Serviceability) are required. Since modern processor architectures provide advanced error and detection technology, offering the possibility to add and remove CPUs becomes extremely important for RAS support.

However CPU hotplug is not just useful to replace defective components it can also be applied in other contexts to increase the productivity of a system. For example on a single system running multiple Linux partitions, as the workloads change it would be extremely useful to be able to move CPUs from one partition to the next as required without rebooting or interrupting the workloads.This is known as dynamic partitioning. Other applications include Instant Capacity on Demand where extra CPUs are present in a system but aren't activated. This is useful for customers that predict growth and therefore the need for more computing power but do not have at the time of purchase the means to afford.

First Get the list of CPU present in your system

    # cd /sys/devices/system/cpu
    # ls -l
    total 0
    drwxr-xr-x 10 root root 0 Sep 19 07:44 .
    drwxr-xr-x 13 root root 0 Sep 19 07:45 ..
    drwxr-xr-x   3 root root 0 Sep 19 07:44 cpu0
    drwxr-xr-x   3 root root 0 Sep 19 07:44 cpu1
    drwxr-xr-x   3 root root 0 Sep 19 07:44 cpu2
    drwxr-xr-x   3 root root 0 Sep 19 07:44 cpu3
    drwxr-xr-x   3 root root 0 Sep 19 07:44 cpu4
    drwxr-xr-x   3 root root 0 Sep 19 07:44 cpu5
    drwxr-xr-x   3 root root 0 Sep 19 07:44 cpu6
    drwxr-xr-x   3 root root 0 Sep 19 07:48 cpu7

Under each directory you would find an "online" file which is the control file to logically online/offline a processor.

Do the following to put a specific CPU offline:

# echo 0 > /sys/devices/system/cpu/cpu7/online

Once the logical offline is successful, check

# cat /proc/interrupts

You should now not see the CPU that you removed. Also online file will report the state as 0 when a cpu if offline and 1 when its online.

To display the current cpu state: # cat /sys/devices/system/cpu/cpu7/online

How To Install Additional true-type (ttf) Fonts in Linux

If you are sitting at a Windows or Macintosh computer right now, then you are looking at a TrueType font as you read this! Fonts are the different styles of typefaces used by a computer to display text.

Installing true-type fonts in Ubuntu/Fedora/OpenSuse is an easy task. One can find thousands of free fonts on the Internet (from sites such as 1001 Free Fonts or DaFont), and with this one could add that extra spice to your documents or websites.

Installation:
First, find and download your desired fonts into /home/nikesh/fonts diretory (user directory). Then extract them and copy to the system fonts directory as follows:

cd /usr/share/fonts/truetype
sudo mkdir customFonts
cd customFonts
sudo cp /home/nikesh/fonts/*.ttf .
sudo chown root.root *.ttf
sudo mkfontdir
cd ..
fc-cache

Now open Open Office Writer or Gimp, and your fonts should be available! You can access your new true type fonts in any graphics, design, text based document application that uses fonts.