Category Archives: Senza Categoria

How to set flush option for USB drives under KDE

You might have noticed long unmount times while using KDE. This is because the drives are mounted without the flush option, which causes part of the data to be written during unmount.

This is done for quicker access and better performance, but makes unmounting a really painful operation.

In my experience it is desirable to mount drives with the flush option.

One way to do this is to add a line to your /etc/fstab containing

/dev/sd*1 /media/pendrive vfat rw,noatime,umask=000,utf8,uid=500,shortname=mixed,flush,noauto,users,exec,suid,dev 0 0

where sd*1 should be corrected with the first available drive letter, usually b if you have a single internal HDD in your machine, or c if you have two.

This is an ugly workaround that only works for the first drive you connect, you use two at the same time the second one will not use flush.

Hope it will be fixed in KDE soon!

Let me know if it works for you!

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Kick start Strigi in KDE 4.3 on Arch Linux

Since I upgraded to KDE 4.3 I have not been using my pc much, so i took me a couple of weekto realize that strigi had stopped working.

Trying to activate it from System Settings returned a nice:

“Strigi service failed to initialize, most likely due to an installation problem”

So what was the problem?

As always the problem was in the backend of the database storage.

It is called sesame2 and is written in Java, and obviously it has always trouble locating the shared object for the Java virtual machine.

This has happened to me on openSUSE, Kubuntu and Arch.

The solutions I had to adopt varied slightly, but the one that saved my day here on Arch appears to be the nicer to date.

What I had to do was adding a line to the file /etc/ld.so.conf which contains a list of folder containing dynamic libraries.

I entered in a terminal:

sudo nano /etc/ld.so.conf

This opens the configuration file using the nano text editor.

Then I added a line for the folder containing the JVM, which varies depending on your distro and architecture, and also if you use openjdk or Sun JRE. Here i list the folders for Sun JRE on Arch Linux 32 and 64 bit:

32 bit: /opt/java/jre/lib/i386/server

64 bit: /opt/java/jre/lib/amd64/server

Then I saved the files, closed nano, ad applied the new settings with the command:

sudo ldconfig

Now System Setting allowed me to activate Strigi, and life was beautiful again.

This has been tested on Arch 32 bit. Any info on you results on other distros, and variations to this how-to, will be included in the main post, so please provide all the feedback you can.

Update: As Sesame2 is not used anymore by Nepomuk, this is probably not useful anymore. The current supported backend is Virtuoso, which is C++ and does not use Java anymore.

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Setting up a Touchpad on Jaunty

Setting up a touchpad on a linux system can be a tricky business.

Back in the KDE3 days you could use Ksynaptics, but no interface has been produced for KDE4. There was Gsynaptics for GNOME, but it doesn’t work anymore, like Touchfreeze.

The latter don’t work due to the decision, taken by the distributions, to disable the shared memory extension of X.org that could consituite a security hole.

The only way to configure a Touchpad to your likings is now a command line utility called xinput, that allows you a really extensive control over the properties of the device.

I will explain briefly how I configured my Synaptics device under Arch Linux on a Dell Vostro 1500 latop, but the same things apply, doing the right changes, on any modern distro, including K/X/Ubuntu Intrepid/Jaunty or later, Fedora 10 or the new Fedora 11 “Leonidas”, Opensuse 11.0 or later.

To begin you need the name of the device to configure. So, type in a terminal emulator:

  • $ xinput list

this will generate a list of the input devices recognized by the X server, with pretty self-explanatory names. My touchpad was listed as “SynPS/2 Synaptics TouchPad”. When you have spotted the right one, you need to know what can or can’t be configure in it. So you need to execute:

  • $ xinput list-props “SynPS/2 Synaptics TouchPad”

Obiously correcting with the name of your device.

Now you need to find the right option in the list. Again, the names are usually self-explanatory, or at least try to be. I wanted to set the touchpad to support mac-style two finger scrolling both horizontally and vertically and disable the annoying tapping-click. Which were respectively “Synaptics Two-Finger Scrolling” and “Synaptics Tap Time”.

so in entered:

  • $ xinput set-int-prop “SynPS/2 Synaptics TouchPad” “Synaptics Two-Finger Scrolling” 8 1, 1

set-set int-prop means that we are setting a property through an integer value, and the first parameter after the property name is the leght of the variable that contains the setting. This is usually not easy to predict, so you need to do some experimentation.

The 1, 1 parameters enable the vertical and horiziontal scrolling respectively.

  • $ xinput set-int-prop “SynPS/2 Synaptics TouchPad” “Synaptics Tap Time” 32 0

This turns the 32 bit value that contains the maximum time allowed between the two consecutive touches that constitute a tapping-click to 0, disabling the tapping feature.

All the variations you might do to the settings will be gone with your first reboot so feel free to experiment.

When you’ve found the ideal settings combination for you you might want to add the commands to your .xinitrc or to a bash script to autorun when you login.

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ElectricSheep and KDE

ElectricSheep is a really cool screensaver, based on a distributed computing project, and is available as

The name “Electric Sheep” is taken from the title of Philip K. Dick’s novel “Do Androids Dream of Electric Sheep?” The title mirrors the nature of the project: computers (androids) who have started running the screensaver begin rendering (dreaming) the fractal movies (sheep).

As one of my favorite movies, Blade Runner, was inspired by that book I could not help but be interested in the project.

It was not love at first sight: as i installed it form ubuntu’s repos, it did not appear in the list of KDE’s screen saver, and launching the executable manually resulted in a black screen.
Then looking at the project page I understood it needed to download some mpg sheep animation in order to work, and I did it manually to avoid waiting.

And then I saw it!

The screen saver is really a joy for the eyes, and I could not help but download about a GB of extra animations.

But the problem still stood: i could not set it as a screen saver from KDE System Settings.

Some investigation showed me that it could not work because a file was missing where kscreensaver looks for the screensavers list.

I also found a replacement for the missing file (here), but it was old and made for KDE 3.
But after some tinkering with that file, here it is a corrected version KDE 4 enabled:

http://dl.getdropbox.com/u/529363/electricsheep.desktop

On Kubuntu ElectricSheep can be enabled by downlading the above file in your home folder, then opening Konsole and entering

sudo cp electricsheep.desktop /usr/share/kde4/services/ScreenSavers/electricsheep.desktop

Now you are ready to go! Enjoy!

UPDATE:

I have updated the file to work with electricsheep 2.7 as it is the only working version and the previous ones have been abandoned.

as Skiro’n points out in the comments Ubuntu is not yet distributing Electrisheep 2.7, which you need to obtain through a dedicated PPA.
As usual you can find the instruction on the ubuntu forums:

http://ubuntuforums.org/showpost.php?p=8270975&postcount=13

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Black flashes in videos with composite effects

Using composite desktop effects in conjunction with X.org 7.4 (or previous) is causing some trouble to possessors of ATI and Intel cards. This version of X.org is included in Ubuntu 8.10 as well as in Opensuse 11.1 and Fedora 10.

When a video is played, no matter with which player, black flashes appear through the video.

I must also point that this how-to was tested under Ubuntu 8.10 Intrepid Ibex with ATI Radeon HD4850 using the proprietary drivers.

There can be several different solution for the problem, what is the best one for you depends mostly on how much computational power you have under the hood.

For a powerful machine the best-looking solution is to set up your player of choice to play videos avoiding that extension. If your player of choice is the dafault Totem or any other gstreamer based player you need to access the gstreamer configuration dialog execing in a terminal:

$ gstreamer-properties

Then go to the [ Video ] and select [ X Window System (No Xv) ] as output device.

If you happen to use VLC you just have to go to [ Tools ] -> [ Preferences ] and then to [ Video ] and select [ X11 video output ] on the output combo box.

Disabling XVideo will disable the hardware acceleration for video playback, raising cpu usage significantly. This might be undesirable with less recent hardware.

If this is your case you should disable compositing effects (3d desktop effects) and wait for a corrected version of X.org, which should be in Jaunty Jackalope.

Latest NVidia propietary drivers also appear to work around the issue, thus solving the problem.

If this helps, comments will be appreciated 🙂

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Hello World

Hi.

This is my new blog, and has been created with three main purposes:

  1. the first one is having a place where i can store the small workarounds and how-tos that I happen to elaborate during the daily usage of my pc
  2. the second one is to exercise my written english,
  3. the third one is familiarizing with wordpress.

I am an enthusiastic GNU/Linux user and I use as a main pc a Dell laptop with a KDE based distro, which happens to be Kubuntu Intrepid 4.2.0 right now. I did stumble upon a number of problems during my continued usage of GNU/Linux and I have often been able to find a solution already written somewhere on a forum or blog. I have decided I should contribute to this by documenting the workarounds I find and publishing the small guides i elaborate.

So here I am, thinking about what will be my first “real” post.

Bye

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