Linux Quota Inconsistency Problems

In our system, we use linux quota to limit users file usage. However, quota database has inconsistencies with file usage of users. Sometimes user has no data, however quota database shows 4KB of usage.

On this problem, quotacheck is recommended. However, quotacheck fully checks the disk. If there are too many files and users, also user files frequently changing; online mode of quotacheck can’t fix inconsistencies.

quota1

Continue reading Linux Quota Inconsistency Problems

Linux Process Invisibility

Hello again, we have given a project in System Programming course. It was expected you to alter the kernel code for process invisibility, when you ps, process can not be seen in the output, if process invisibility flag is “1”.

The project was modifying the linux kernel for process invisibility, writing a system call for setting the invisibility flag and writing a user-space program.

Project was developed at Xubuntu 9.10 guest on Windows 7 host. Eclipse (with CDT and Remote System Explorer plugins) was the development IDE. Putty SSH client was also used for executing commands and “command copy/paste” availability. VirtualBox was the virtual machine supervisor.

ATTENTION: This code is experimental. If you try, it will be your own responsibility.
Continue reading Linux Process Invisibility

KDE4 and Dual Monitors

KDE4 has brought a new concept to desktop by Plasma. However, it was not considered that Plasma should work on more than one monitors. It has rumours that KDE 4.2 has a fix for multi-monitoring, this fix is not working. While I was searching for the problem, I found an alternative solution to monitoring on KDE-Forums (It redirects to Gentoo-Wiki).

  1. Backup your xorg.conf file (/etc/X11/xorg.conf ).
    cp /etc/X11/xorg.conf /etc/X11/xorg.conf.backup
  2. Configure your xorg.conf file for dual monitors. I don’t now how ATI is configured, but for NVIDIA you can use nvidia-settings program. You must configure both screen as seperate screen. Your main screen’s height should be greater than second’s and Xinerama should be disabled.  Then click “Save to X Configuration File” and save it.
    nvidia-settings
  3. Install ICEWM by your default repository manager.
    For Gentoo:

    emerge -av icewm
  4. Restart your Xorg server by
    Ctrl+Alt+Backspace.
  5. Open a console then write:
    DISPLAY=":0.1" icewm
  6. If you want to work with “icewm” every start of your computer:
    echo 'DISPLAY=":0.1" icewm &' > ~/YOUR_KDE_FOLDER/Autostart/icewmstart.sh

    If folder name is “.kde”:

    echo 'DISPLAY=":0.1" icewm &' > ~/.kde/Autostart/icewmstart.sh

And then my dual monitors 🙂

dualmonitors

If your second monitor left of the main monitor you can configure xorg.conf file like this:
Find the line:

    Screen      1  "Screen1" RightOf "Screen0"

Then change to:

    Screen      1  "Screen1" LeftOf "Screen0"