C.4. Problems After Installation

C.4.1. Trouble With the Graphical GRUB Screen on an x86-based System?

If, for some reason, you need to disable the graphical boot screen, you can do so, as root, by editing the /boot/grub/grub.conf file and then rebooting your system.

To do this, comment out the line which begins with splashimage in the grub.conf file. To comment out a line, insert the # character at the beginning of the line.

Once you reboot, the grub.conf file will be reread and your changes will take place.

You may re-enable the graphical boot screen by uncommenting (or adding) the above line back into the grub.conf file.

C.4.2. Trouble With the Graphical LILO Screen on an x86-based System?

If, for some reason, you need to disable the graphical boot screen, you can do so, as root, by editing the /etc/lilo.conf file and then rerunning LILO.

First, as root, comment out (or delete) the line which reads message=/boot/message in the /etc/lilo.conf file. To comment out a line, insert the ; character at the beginning of the line. Next, rerun LILO by typing /sbin/lilo -v. The next time you boot, the text LILO: prompt appears, as used in previous Red Hat Enterprise Linux releases.

You may re-enable the graphical boot screen by adding (or uncommenting) the above line back into the lilo.conf file and rerunning LILO.

C.4.3. Booting into a Graphical Environment

If you have installed the X Window System but are not seeing a graphical desktop environment once you log into your Red Hat Enterprise Linux system, you can start the X Window System graphical interface using the command startx.

Once you enter this command and press [Enter], the graphical desktop environment is displayed.

Note, however, that this is just a one-time fix and does not change the log in process for future log ins.

To set up your system so that you can log in at a graphical login screen, you must edit one file, /etc/inittab, by changing just one number in the runlevel section. When you are finished, reboot the computer. The next time you log in, you will have a graphical login prompt.

Open a shell prompt. If you are in your user account, become root by typing the su command.

Now, type gedit /etc/inittab to edit the file with gedit. The file /etc/inittab will open. Within the first screen, a section of the file which looks like the following appears:

# Default runlevel. The runlevels used by RHS are:
#   0 - halt (Do NOT set initdefault to this)
#   1 - Single user mode
#   2 - Multiuser, without NFS (The same as 3, if you do not have networking)
#   3 - Full multiuser mode
#   4 - unused
#   5 - X11
#   6 - reboot (Do NOT set initdefault to this)
# 
id:3:initdefault:

To change from a console to a graphical login, you should change the number in the line id:3:initdefault: from a 3 to a 5.

	Warning
	Change only the number of the default runlevel from 3 to 5.

Your changed line should look like the following:

      	id:5:initdefault:
      
    

When you are satisfied with your change, save and exit the file using the [Ctrl]-[x] keys. A message appears telling you that the file has been modified, and asking you to confirm your change. Type [Y] for yes.

Now, your next login after reboot will be from the graphical screen.

C.4.4. Problems with the X Window System (GUI)

If you are having trouble getting X (the X Window System) to start, you may not have installed it during your installation.

If you want X, you can either install the packages from the Red Hat Enterprise Linux CD-ROMs or perform an upgrade.

If you elect to upgrade, select the X Window System packages, and choose GNOME, KDE, or both, during the upgrade package selection process.

C.4.5. Problems When You Try to Log In

If you did not create a user account in the Setup Agent, log in as root and use the password you assigned to root.

If you cannot remember your root password, boot your system as linux single.

Itanium users must enter boot commands with elilo followed by the boot command.

If you are using an x86-based system and GRUB is your installed boot loader, type e for edit when the GRUB boot screen has loaded. You are presented with a list of items in the configuration file for the boot label you have selected.

Choose the line that starts with kernel and type e to edit this boot entry.

At the end of the kernel line, add:

single

Press [Enter] to exit edit mode.

Once the GRUB screen has returned, type b to boot into single user mode.

If you are using an x86-based system and LILO is your installed boot loader, press [Ctrl]-[x] to exit the graphical LILO screen and gain access to the LILO boot: prompt.

Next, enter linux single at the LILO boot: prompt.

Once you have booted into single user mode and have access to the # prompt, you must type passwd root, which allows you to enter a new password for root. At this point you can type shutdown -r now to reboot the system with the new root password.

If you cannot remember your user account password, you must become root. To become root, type su - and enter your root password when prompted. Then, type passwd <username>. This allows you to enter a new password for the specified user account.

If the graphical login screen does not appear, check your hardware for compatibility issues. The Hardware Compatibility List can be found at:

http://hardware.redhat.com/hcl/

C.4.6. Is Your RAM Not Being Recognized?

Sometimes, the kernel does not recognize all of your memory (RAM). You can check this with the cat /proc/meminfo command.

Find out if the displayed quantity is the same as the known amount of RAM in your system. If they are not equal, add the following line to the /boot/grub/grub.conf:

mem=xxM

Replace xx with the amount of RAM you have in megabytes.

In /boot/grub/grub.conf, the above example would look similar to the following:

#NOTICE: You have a /boot partition. This means that
#        all kernel paths are relative to /boot/
default=0
timeout=30
splashimage=(hd0,0)/grub/splash.xpm.gz
title Red Hat Enterprise Linux (2.4.21-1.1931.2.399.ent)
        root (hd0,0)
        kernel /vmlinuz-2.4.21-1.1931.2.399.ent ro root=/dev/hda3 mem=128M

Once you reboot, the changes made to grub.conf will be reflected on your system.

Or, you can add the following line to the /etc/lilo.conf file:

append="mem=xxM"

Note, that the append command works in both GRUB and LILO.

Replace xx with the amount of RAM you have in megabytes. Remember that per-image append lines completely overwrite the global append line. It might be worth adding this to the per-image descriptions.

In /etc/lilo.conf, the above example would look similar to the following:

boot=/dev/sda
      map=/boot/map
      install=/boot/boot.b
      prompt
      timeout=50

      image=/boot/vmlinuz-2.4.21-1.1931.2.399.ent
              label=linux
              root=/dev/sda1
              initrd=/boot/initrd-2.4.21-1.1931.2.399.ent.img
              read-only
              append="mem=128M"

Remember to run /sbin/lilo -v after changing /etc/lilo.conf.

Note that you can also produce the same effect by actually passing this option when you are specifying the label/image to use in GRUB or LILO.

Once you have loaded the GRUB boot screen, type e for edit. You are presented with a list of items in the configuration file for the boot label you have selected.

Choose the line that starts with kernel and type e to edit this boot entry.

At the end of the kernel line, add

mem=xxM

or

append=xxM

where xx equals the amount of RAM in your system.

Press [Enter] to exit edit mode.

Once the GRUB screen has returned, type b to boot with your new RAM specifications.

At the graphical LILO screen, press [Ctrl]-[x] to exit to the boot: prompt. Next, enter the following at the boot: prompt:

linux mem=xxM

Itanium users must enter boot commands with elilo followed by the boot command.

Remember to replace xx with the amount of RAM in your system. Press [Enter] to boot.

C.4.7. Your Printer Will Not Work

If you are not sure how to set up your printer or are having trouble getting it to work properly, try using the Printer Configuration Tool.

Type the redhat-config-printer command at a shell prompt to launch the Printer Configuration Tool. If you are not root, it prompts you for the root password to continue.

C.4.8. Problems with Sound Configuration

If, for some reason, you do not hear sound and know that you do have a sound card installed, you can run the Sound Card Configuration Tool (redhat-config-soundcard) utility.

To use the Sound Card Configuration Tool, choose Main Menu => System Settings => Soundcard Detection. A small text box will pop up prompting you for your root password.

You can also type the redhat-config-soundcard command at a shell prompt to launch the Sound Card Configuration Tool. If you are not root, it prompts you for the root password to continue.

To run the text-based configuration tool, as root, type sndconfig in a terminal window. Note, the sndconfig application is not installed by default but can be found on the Red Hat Enterprise Linux CD-ROMs.

If the Sound Card Configuration Tool does not work (if the sample does not play and you still do not have audio sounds), there are alternatives, although they are not quite as simple as running the Sound Card Configuration Tool. You can edit your modules.conf file (this strategy is not recommended for most new users), or refer to the documentation that came with your sound card for more information.

C.4.9. Apache-based httpd service/Sendmail Hangs During Startup

If you are having trouble with the Apache-based httpd service or Sendmail hanging at startup, make sure the following line is in the /etc/hosts file:

127.0.0.1  localhost.localdomain  localhost

C.4.10. Trouble with NVIDIA chipset

If you have an NVIDIA chipset and have just updated your kernel, you may experience problems with the video card, such as not having any video output.

If you experience a similar problem, you should download the latest kernel drivers available for your NVIDIA chipset. For more information, refer to:

http://www.nvidia.com/view.asp?IO=linux_display_1.0-3123