Author Archive

Linux Documentation

February 7, 2009

Hi everybody!

This time let’s talk about something that every single Linux user – from the typical user to the system admin – almost use it everyday !!

Wow !! That’s cool. But, What is it?

Yeah as the title tels you, “Linux Documentation”.

So, What is the Linux Documentation? why we use it rapidly? and how to use it? that is what this post about.
We will not cover all Documentation tools in this post, but it will be followed by other posts to describe the next tools isA.

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System time isn’t correct

August 27, 2008

This problem was always facing me in Ubuntu.

the problem is that the system clock is some hours forward or backward, and that’s because Ubuntu by default considers that your system clock is adjusted to the UTC time.
So if your system clock is adjusted to your local time, here the problems will start.

Now you should configure your system to consider that you system clock is adjusted to your local time. So, you should do that:-

Open this file with your favorite text editor:

/etc/default/rcS

Find this line:

UTC=yes

replace it with:

UTC=no

Now restart your machine and you will find that your system time is correct.

Compiz Crash

August 23, 2008

Yeah.. Compiz does it alot, Especially with Nvidia graphic cards.

So, what happen’s?

  • First you will find that the border around all windows is gone!! it disappears!!.
  • then if you open a terminal you will see that the text is not visible in it!!!
  • some times you find that Minimization an Maximization is not working.

Do you know why does it all hapen?

that’s because compiz which is your window manager is crashed!! and unfortunately, the window manager is the application that is responsible for making a border around your windows to enable you to resize or drag the window.
It’s also responsible for the minimization and maximization for windows, desktop effects, etc

Now I think you see how annoying it is when it craches!!

So, what is the solution?

some times.. just pressing Alt+F2 then writing this command solves the problem:

compiz –replace

but sometimes it dosen’t solve the problem and when you run this command in a terminal you get an error output like that:

Checking for Xgl: not present.
Detected PCI ID for VGA: 01:00.0 0300: 10de:0185 (rev c1) (prog-if 00 [VGA controller])
Checking for texture_from_pixmap: present.
Checking for non power of two support: present.
Checking for Composite extension: present.
Comparing resolution (1024×768) to maximum 3D texture size (2048): Passed.
Checking for nVidia: present.
Checking for FBConfig: present.
Checking for Xgl: not present.
Attempted to unregister path (path[0] = org path[1] = freedesktop) which isn’t registered
Attempted to unregister path (path[0] = org path[1] = freedesktop) which isn’t registered
Attempted to unregister path (path[0] = org path[1] = freedesktop) which isn’t registered

Or sometimes like that

Checking for Xgl: not present.
No whitelisted driver found
aborting and using fallback: /usr/bin/metacity

this Error happens with Nvidia graphic cards and the soulution is so simple:

first: check if you have the nvidia-glx driver installed in your system.

second: if it’s installed but you still have the same problem then you should edit this file by hand:

/etc/X11/xorg.conf

and in the “Screen” section add this line:

Option “AddARGBGLXVisuals” “True”

now restart your X server by pressing Alt+Ctrl+BackSpace and you should find that the problem is solved.

if it’s not add this line also to the same file in the same section (But I Really Don’t Recommend That, Do it only if you have to)

Option “DisableGLXRootClipping” “True”

I hope this helps anybody.

Linux Installation & Partitioning

June 23, 2008

Hey everybody !!

in this post we will talk about the Linux installation but before we start let’s see how does Linux deal with the hard disk.

Partitioning Scheme :-

First : the name of your hard disk is determined by the technology it uses and the way you connect it to your computer like that:-

  • ATA disk starts with (hd)

  • SATA or the SCSI disks starts with (sd).

But Fedora started to use (sd) for all HDDs starting from Fedora core 7 and UBUNTU also does that.

the next character is dedicated depending on your hard disk status so let’s assume that you had an ATA HDD, the scheme will be like that:-

  • hda primary master

  • hdb primary slave

  • hdc secondary master

  • hdd secondary slave

now let’s see how does the partitions names look like?

The data about your partitions is stored in the first sector of your hard disk which called the MBR (Master Boot Record) in 64 bytes only which is only enough to fully describe just 4 partitions. These partitions are called primary partitions and it takes number from 1 to 4. so lets assume that you have a primary master ATA disk then the partitions will look like that:-

  • hda1 the first primary partition

  • hda2 the second primary partition

  • hda3 the third primary partition

  • hda4 the fourth primary partition

if you need more partitions then you need to make an (Extended partition) which is a primary partition that is capable of holding other sub-partitions called (Logical partitions).

Note: Theoretically you can make unlimited amount of logical partitions in the extended partition but Linux limits that number to 59 in the IDE disks and 11 in SCSI disks.

Logical partitions takes numbers starts from 5. this means that (hda5) is the first logical partition in your disk whatever the number of your primary partitions is and the second logical partition will be (hda6) etc.

In the graph we can see that:-

  • hda1 and hda2 are the first two primary partitions.

  • hda3 is also a primary partition but it is an extended partition which only holds two logical partitions (hda5 and hda6).

  • hda5 is the first logical partition in the disk so takes number 5.

  • hda6 is the second logical partition in the disk so it takes number 6.

  • hda4 is the fourth primary partition so it has no relations with the logical ones and it takes number 4.

The root file system :-

Now let’s see what is the requirements to install Linux.

At least you need one partition to install Linux and this partition will be called the root file system which holds your data or link to it. So the root file system will be mounted as “ / “ (slash), and all other partitions will be mounted under it like that

now “dev” will be called “/dev” and “home” will be “/home” etc. and we will speak about the functionality of these main directories later.

You also can make any main directory of those a separate file system (partition) and it will be mounted under the root file system “/” and it will look like any other directory. That’s may be useful in some cases which also will be discussed later.

the file system that should be created on that partition should be (ext2 or ext3) file system but ext3 is more efficient.

SWAP area :-

You can start your installation with the root file system only, but if your RAM is small (256M or less) so you need to make a place to be considered as virtual memory. This area must be a separate partition – unlike Windows – this partition use’s the “swap” file system and it’s size should be twice as much as your RAM size for the best performance.

Installation :-

Now we can start the installation and as we said before we will work on the three major distributions. So we can’t be very verbose. So let’s speak about the most important and sensitive part of the installation which is Partitioning. And the rest of the installation is simple and easy to understand if you read the tips carefully.

I recommend that you should have a backup of your important data because there are two kinds of people, people who make backups and people who never delete a file. So, always have backups.

Lets Start Partitioning:

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Overview about Linux

June 16, 2008

History Stuff:-

Early in 1970 at AT&T Bell labs a team leaded by ken Thompson and Dennis Ritchie made the UNIX operating system for the PDP-7 machines which was completely written in the PDP-7 assembly and it was multiuser multitasking operating system and also included initial text processing system then later in 1973 the UNIX was first written in C programming language .

The UNIX operating system was free and open source and it helped to develop so many other UNIX-Based operating systems like the BSD and the Sun OS which became Solaris now but in 1983 when a system administrator in MIT his name was Richard Stallman received a UNIX copy which was UNIX-System V without it’s source code and he couldn’t obtain it until he signed a Non-Disclosure Agreement NDA which made the source code useless, so he decided to start a project to develop a new UNIX-Like operating system written from scratch and it will be free software. this project is called GNU (Gnu’s Not UNIX) – yes it’s a self referencing acronym SRA – and it was started in 1984 by Richard Stallman after he had resigned from MIT.

Gnu’s developers made a lot of tools for the new OS like :-

  • GCC: the gnu C compiler
  • Glib: gnu library
  • Bash: command line interpreter

But unfortunately the kernel wasn’t finished (it was finished in late 1990s and it called Hurd but Linux was already thriving) so they used the kernel that Linus Thorvald made.

Linus Thorvald also managed to combine the GNU C compiler with the new kernel and the first version of the Linux kernel was announced in September 1991 and it was rapidly developed since that till now.

Why Linux?

Everybody will ask now why should we use Linux? So, I’ll try to list the advantages of Linux quickly which are:-

  • Open source operating system.
  • It’s multiuser multitasking operating system.
  • Very secure.
  • High performance.

And so many other features but the most important one is that Linux is open source under the GPL (Gnu General Public License) read more about it from here

Linux has so many distributions which also called Linux flavors and among all of these distros there is only three major distros which are (Debian, Red Hat and Slackware) and most of the other distros are based on these ones. So, we will try to cover these three distros in any topic we will post to guarantee that your favorite flavor is included.

In the next post we will get down to work with Linux and we will start with the Installation. So, keep it up 😀