Imaging and a little bit of OSS

I followed the procedure outlined by UbuntuGeek, but some of the things are little different – at least when I installed it today.

First, you’ll need to add the repository which contains the deb for Chrome.

sudo gedit /etc/apt/sources.list

Assuming you are running Karmic Koala (Ubuntu 9.10), you’ll need to add the following two lines towards the end of that file.

deb http://ppa.launchpad.net/chromium-daily/ppa/ubuntu karmic main
deb-src http://ppa.launchpad.net/chromium-daily/ppa/ubuntu karmic main

Next, you’ll have to retrieve the PGP keys for this repository.

sudo add-apt-repository ppa:chromium-daily/ppa

Update the sources,

sudo apt-get update

And then instal Chrome

sudo apt-get install chromium-browser

After the installation is successful, you can launch the browser, and import settings from Mozilla Firefox. However, Firefox needs to be closed when the importing of options and favourites is taking place. When Chrome restarts, it will have options configured like you had them in Firefox. The are no add-ons that I could find for Chrome, though – Adblock Plus and Video Download Helper are the two plugins that would make me stick with Firefox for a while.

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Sometimes when you change some of the IP settings, or are using a different wireless card on a machine that has been registered with a server, and for many other reasons, you might have encountered a warning which would’ve looked like this:

@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that the RSA host key has just been changed.
The fingerprint for the RSA key sent by the remote host is
f2:92:1d:da:81:2a:d7:16:0a:48:f0:43:20:1c:f4:b5
………………..

The simplest way to deal with this is to remove the ~/.ssh folder, however this clears out all the exchanged keys with all the ssh machines you have ever communicated with. Removing the ~/.ssh folder would mean that each time you reconnect to a SSH server that you have previously connected to, you will have to confirm that the connection is secure and all that.

There is however another simple way to change just the entry for a specific server in question. At the terminal type in -

ssh-keygen -R name_of_the_server.com

name_of_the_server.com in the above example would need to be replaced by the actual server name that you are trying to connect.

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The snapshot before the LTS version of Ubuntu is out now! Karmic Koala would be supported for about another year after which one will have to upgrade to  Lucid Lynx, which would be coming out in April 2010, this the name Ubuntu 10.04 LTS.

Karmic has been functional on my machines since Alpha 3 – so no surprises await me as of today. But I would be posting some observations and neat tricks that one can use with Karmic Koala and Ubuntu Linux in general.

The first trick is to use a torrent for downloading the .iso image instead of downloading it directly from some mirror. The advantage of doing that is that you get much faster download rates when using P2P networks for downloading the .iso image, this is especially true for a week since the release, since the mirrors literally crawl to a halt from all the traffic following the release.

Karmic Koala (Ubuntu 9.10): Header used during release

The listing of all the torrents for Ubuntu 9.10 codenamed Karmic Koala can be found at:

Karmic Koala (Ubuntu 9.10) : List of releases on bit torrent

If you come across some performance issues, you can always take your questions to Ubuntu Forums, where you can search if someone has already resolved that issue, and if not, post a query.

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For the first time I was able to get VNC to work with Ubuntu with Gnome session instead of a xterm on gray background. The steps involved were exactly the same as I was following earlier, with one exception:  the setup of xstartup in the ~/.vnc folder.

For your xstartup file in ~/.vnc (the “.vnc” folder in
your home directory), you need the following:
—————————–
#!/bin/sh

# Uncomment the following two lines for normal desktop:
# unset SESSION_MANAGER
# exec /etc/X11/xinit/xinitrc

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
xterm -geometry 80×24+10+10 -ls -title “$VNCDESKTOP Desktop” &
gnome-session &
# twm &
————————

instead of uncommenting the lines as the script suggests, you change the window manager to gnome-session

make sure restart vnc4server

The line which got Gnome working was “gnome-session &”

========================================

Now for all the steps involved (works in Karmic Koala Alpha 2, Ubuntu 9.10, kernel 2.6.30-10)

1. Install ssh server, ssh client, VNC viewer, VNC server, and xinetd

sudo apt-get install openssh-server openssh-client vnc4server xinetd  vncviewer

2. Setup the ssh password for your login

ssh-keygen

3. Test out the ssh server by typing in

ssh localhost  or ssh your_login@your_ip_address

4. Then create a vnc password

sudo vncpasswd ~/.vncpasswd

5. Edit the xstartup file in ~/.vnc directory

For your xstartup file in ~/.vnc (the “.vnc” folder in
your home directory), you need the following:
—————————–
#!/bin/sh

# Uncomment the following two lines for normal desktop:
# unset SESSION_MANAGER
# exec /etc/X11/xinit/xinitrc

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
xterm -geometry 80×24+10+10 -ls -title “$VNCDESKTOP Desktop” &
gnome-session &
# twm &
————————

instead of uncommenting the lines as teh script suggests, you change the window manager to gnome-session

6. Create a VNC desktop

vnc4server :1 -geometry 1024×768

7. Then to tunnel into your VNC desktop, first create a SSH tunnel by logging into SSH with the comand:

ssh -L 5901:your_ip_address:5901 your_username@your_ipaddress

8. Finally, load up your VNC desktop

vncviewer localhost:1

And now you are ready to use connect to your machine remotely and use t

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In order to find the exact address maps and to see a list of devices attached to different ports one can use:

sudo lshw

This outputs the hardware specs to the terminal. However in order to check the detailed specs in a graphical format, we need to use the lshw-gtk command. Before you do that, you first need to install it using:

sudo apt-get install lshw-gtk

Then running the lshw-gtk as sudo brings up the list of hardware that you can browse through. It is similar to checking the hardware information from Windows’ control panel.

List detailed hardware specs under linux: lshw-gtk

That’s it. It provides you with relevant information about your processor, memory, display cards, and also some information about the devices connected to USB ports. A quite handy tool for Linux.

slash_boot Linux and OSS hardware, Linux and OSS

I had to create a movie/animation out of a series of images that I had in my folder. There were several methods described on several forums which suggested using GIMP for creating GIF files from JPG or PNG files when one is using Linux. Now the problem was that I had 70 files in total and it would have taken me a long to time to add all those images to GIMP in order to create my animation file.

Then I read somewhere that we can actually create GIF images in command line mode using Imagemagick. But to do so you need to have Imagemagick installed on your system. To install it in Ubuntu, run:

sudo apt-get install imagemagick

This program has several features that would let you do all sorts of things with images. I was interested in converting a bunch of PNG files into an animated GIF file. To do so, we need to  rename the files in a way that they would lie in a sequence when arranged alphabetically (if you plan on doing it the easy way). Suppose you have files named slide_01.png, slide_02.png, slide_02.png….slide_xx.png, and you want to convert them to movie.gif, we run:

convert -delay 10 -loop 0 slide*.png movie.gif

The parameter delay inserts a desired delay between two consecutive slides. The number x used for delay inserts 10x milliseconds of delay between two frames. Loop parameter 0 makes it repeat infinitely.

If you had files with non-uniform names, then you need to input each of them in a sequence after the delay and loop parameters. Suppose you have file summer.jpg, fall, winter.jpg, fall.jpg and spring.jpg and you want to order them as fall, winter, spring and summer in the gif image seasons.gif with a 1 second delay between each of them, use:

convert -delay 100 -loop 0 fall.jpg winter.jpg spring.jpg summer.jpg seasons.gif

Here are some animations of numbers from 0 to 9 with varying delays.

The delay values specified the above cases were: 1, 5, 15, 25, 50 and 100.

GIF animation with 10 millisecond frame delay

GIF animation with 50 millisecond frame delay

GIF animation with 150 millisecond frame delay

GIF animation with 250 millisecond frame delay

GIF animation with 500 millisecond frame delay

GIF animation 1 second frame delay

=================

slash_boot Imaging, Linux and OSS conversion, imagemagick, Imaging, jaunty, Linux and OSS

A few days ago an article appeared on geekzone that described how the KDE and Gnome based linux desktop systems are vulnerable to virus and trojans. The point that jumped out was a statement by the blog author: “False sense of security is worse than no security”, and I’ve been guilty of having this false sense of security all along. By all along I mean whenever I was logged in to some Linux distro.

The article is titled: How to write a Linux virus in 5 easy steps

Linux is vulnerable to Viruses and Trojans

Its an interesting read, and one can only hope that everyone in the Linux community takes this as a serious flaw in their beloved OSs and helps out in addressing this issue whichever way they can.

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The system beep is one of the most distracting and annoying occurrences when you are doing some constructive work. Be it working in a text editor, or a terminal, or a program window – wherever a sound notification is programmed into any module, it emits a fairly audible beep. To disable the beep, we have to disable the PC speaker by adding it to the blacklist.

sudo gedit /etc/modprobe.d/blacklist

Add the following line to the end of that file:

blacklist pcspkr

Save and exit. Then in terminal,

sudo modprobe -r pcspkr

This completely turns off the speaker. You won’t hear your system beep, even if there is something truly wrong. If you are doing something critical and need to rely on the beeps, comment out the line from the blacklist and run the modprobe command. Beeping will restart.

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Recently I bought a student version of Matlab2008b. It was for Linux platform. Here’s my experience with installing the program on 64-bit Linux (Debian) architecture, what problems arose along the way and how they were addressed – with help from Mathworks tech support.

Matlab at work

Installing Matlab 7.7 (i.e. Matlab2008b) the old fashioned way was a breeze, but getting it to actually run on 64-bit architecture involved a few steps, which I didn’t know. I sent a query to Mathworks tech support saying:

The installation files were able to successfully install Matlab2008b on Ubuntu 9.04 (Jaunty), however, the program failed to load since it cannot find the jre files for 64-bit architecture. Is there a workaround for running the 32-bit program on 64-bit platform?

And they replied with a procedure to be followed to make that happen:

Yes – here is a full walkthrough:

1) When running the MATLAB installer (install_unix.sh) use the -glnx86 flag.  This will allow it to install properly on a 64-bit Linux machine:

./install_unix.sh -glnx86 -t

2) Once the installer is finished, you will need to activate through mathworks.com, as the activation client will not work properly on 64-bit computers.  To do so, follow the instructions below:

http://www.mathworks.com/support/solutions/data/1-3YZBZ6.html?solution=1-3YZBZ6

3) Once MATLAB is installed and activated, you will need to run MATLAB using the same -glnx86 flag that you used to install:

$MATLAB/bin/matlab -glnx86

(where $MATLAB is the MATLAB installation folder)

NOTE: Some users have problems loading the JRE when running in this configuration.  Creating a symlink in $MATLAB/sys/java/jre named glnxa64 pointing to glnx86 should resolve this issue.  You can do this with the following command:

ln -s $MATLAB/sys/java/jre/glnx86 $MATLAB/sys/java/jre/glnxa64

And now it works. Haven’t had any GUI crash on me yet, but it been less than an hour since I’ve been using it. One way to avoid typing matlab -glnx86 before each launch is to create a local alias.

gedit ~/.bashrc

Under one of the listing for aliases, you can type in:

alias mat='matlab -glnx86 &'

Save and exit. Then onward, you can launch the program by simply typing in mat in the terminal.

In case your compiz is enabled, you might not see the menus correctly. To fix that problem, you have to run the following command at the terminal.

export MATLAB_JAVA=/usr/lib/jvm/java-6-sun/jre/

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Some of the repositories which hold the libraries for mplayer seem to be broken in the Alpha 4 release of Ubuntu 9.04 (Jaunty Jackalope). What’s surprising is that the mplayer installation in Alpha 3 meets all the dependencies and fetches the files correctly, however that for Alpha 4 don’t.

One workaround for vlc is to install libx264-dev, and then install VLC:

$sudo apt-get install libx264-dev vlc

This still leaves unmet dependencies for mplayer.

rick@lithium:~$ sudo apt-get install mplayer
Reading package lists… Done
Building dependency tree
Reading state information… Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
mplayer: Depends: libx264-59 (>= 1:0.svn20080408) but it is not installable
E: Broken packages
rick@lithium:~$

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After running the update commands yesterday:

sudo apt-get update && sudo apt-get upgrade

There were a few nvidia video card drivers that got installed. There were several of them;

fglrx-modaliases
nvidia-173-modaliases
nvidia-177-modaliases
nvidia-180-modaliases
nvidia-71-modaliases
nvidia-96-modaliases

Once these modaliases were installed, I performed a search for hardware drivers. This time the search showed that there were several drivers that could work with my Nvidia GeForce 7300 graphics card.

Nvidia graphics drivers after Jaunty update (Feb 2, 2009)

The recommended driver was version 180. After installing the driver, the computer needs to be restarted for the driver to take effect.  Accordingly, I restarted the computer and now the Nvidia graphics are fully enabled.

One of programs that I use frequently is still quite buggy. The gnome-do program, that performs the same functions as Quicksilver (Mac) was working really well under Intrepid. It keeps crashing all the time under Jaunty. By the time Jaunty is in Alpha 4, I think the problem would be sorted out.

While the nividia graphics card drivers have been release for Jaunty, the ones for ATI still aren’t. The graphics on my Toshiba Satellite that has an ATI graphics accelerator card are still using the system memory. We’ll have to wait for the ATI drivers in order for the card to start working in Ubuntu 9.04.

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The Alpha-3 version of Jaunty became available two days past the scheduled release date. It included the kernel 2.6.28.4. It’s the first (alpha) release to include a kernel that supports EXT4 filesystem. The EXT4 became officially available in Dec 2008, and in less than a month it was incorporated into the 2.6.28 kernel.

There are several sites which post the performance benchmarks for EXT4 compared with other filesystems.

1 2

EXt4 is supposed to be much faster than existing filesystems. Several people have reported a booting time between 21 and 25 seconds, which is the time taken from bootloader selection till the login screen appears.

But beyond fast loading the alpha leaves a lot of room for improvement. Its integration with the /home/user partition is pretty buggy. One of the least stable module appears to be the alsamixer. The interface of volume applet has been changed significantly and is actually a lot less intuitive and quite inefficient.

Screenshot of volume control applet

As you see, the controller has a horizontal slider instead of the conventional vertical slider. More interestingly, double clicking on the volume control icon doesn’t open up the mixer like it used to. I’ve yet to figure out the workings of this applet.

Perhaps I might have figured out its usage, but I can’t vouch for the accuracy. One way to do it is:

Volume control applet (right click) >> Preferences >> HDA xxxx (Alsa Mixer) >> Select the device you want to control >> Close

Screenshot of volume control prefernces

I was able to change the line-in volume for use with a TV tuner card by the procedure I described above.

However the alsa module is very unstable in its present state. It causes one or more applications to crash at random. Most crashes were encountered when playing some form of flash media. Skype fails to load altogether. As soon as the login information is entered, the program coredumps with the following errors:

user@user-computer:~$ skype
ALSA lib ../../src/conf.c:2700:(snd_config_hooks_call) Cannot open shared library libasound_module_conf_pulse.so
ALSA lib ../../../src/control/control.c:909:(snd_ctl_open_noupdate) Invalid CTL hw:0
Aborted (core dumped)
user@user-computerf:~$

The video drivers for nvidia cards have yet to be released. Searching for Hardware Drivers yields a blank window. The drivers nvidia-glx-17x and nvidia-glx-96 are present in the repositories but the installation messes up the X and gdm loading. The only way to get back to X, is to remove the nvidia drivers and install ubuntu-desktop along with xorg. Once its done, typing

startx

gets you back into GDM.

On wireless side, ath5k is not included in the default distribution and it is still quite a bit of hassle to obtain it from backports and blacklisting the ath_pci modules *.

All in all, there is a lot that needs to be done w.r.t. Ubuntu 9.04 before it is released as a beta and then finally as an official release in April. It would be nice to try out a fresh install including a brand new /home directory.

ETA: * The Alpha 4 release of Ubuntu and Kubuntu contained ath5k, even in the LiveCD, thus the part about Ubuntu (jaunty) not having support for Atheros cards out of the box is no longer valid. I haven’t heard other testers say anything since Alpha 4 came out, so I guess it must be working for quite a number of folks. Still no support for the ATI graphics card though.

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