CentOS 5 on SATA drives

Making SATA drives work in Linux still seems a bit of a dark art.

I had a failure yesterday, with CentOS 5 refusing to even enter rescue mode or install procedure, asking for the driver.

Many suggestions are posted on various sites, most of them indicating that changing BIOS settings from SATA to IDE, or even to RAID should allow to get past the problem. None of these worked for me. What did work, was giving all-generic-ide parameter to the kernel.

So, to entering rescue mode (one goes there usually to fix bootloader, such as grub, configuration problems), place you first installation CD (od DVD) in the drive, start the machine, and wait for the boot: prompt. Then type:

boot: linux rescue all-generic-ide

For fresh installs, just start up the machine just as described above, except that you will enter:

boot: linux all-generic-ide

Making the best of VESA drivers in CentOS 5

Teaching in Edinburgh, on machines that flatly refuse to switch between CLI and GUI. Going into any of the CLI (CTRL_ALT_F1 - F6) is no problem, but restarting the X server or switching back from CLI gives random, hardly ever successful results.

Last week a couple of colleagues (Donald and Gary) were saying about dropping resolution, this week one of our techies (Stuart) found advice about vesa. Neither approach worked on its own, but put them together (albeit in a slightly modified way) and all is well.

If your GUI is working
Select:
System --> Administration --> Display (may need to put root's password if logged in as ordinary user)
Select Hardware tab
Configure "Monitor Type" to Generic LCD --> LCD Panel 1024 x 768
Configure "Video Card" to "vesa - Generic VESA-compliant video cards"
Do the OK three times.

I always check the config on RHEL/CentOS before restarting the GUI. Either look inside the configuration file (/etc/X11/xorg.conf, attached below) or check the System-->Administration-->Display-->Hardware settings (note that the vesa driver will be described as "Unknown video card").

To restart the GUI press CTRL-ALT-Backspace - all should be well.

If your GUI is NOT working

If the GUI is broken to the point you can't use the method above, you can hack the file directly, or enter the configuration screen from the command line. For that, log in as root on CLI (enter CLI with CRTL-ALT-F1), then enter:

# system-config-display

The system will use basic GUI settings to 'draw' the menus. Use the solution as provided above to complete the steps.

To start the GUI, the cleanest method I found is to 'recycle' runlevels: change into runlevel 3, then into runlevel 5.

# init 3
Several messages will be printed, when you see one fron "anaconda" hit enter. That will re-print the prompt. Now type:

# init 5

XWindows should start successfully!


===============================================
sample /etc/X11/xorg.conf using defaults for both the server and the monitor
===============================================
Section "ServerLayout"
Identifier "single head configuration"
Screen 0 "Screen0" 0 0
InputDevice "Keyboard0" "CoreKeyboard"
EndSection

Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
Option "XkbModel" "pc105"
Option "XkbLayout" "gb"
EndSection

Section "Monitor"

### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
Identifier "Monitor0"
ModelName "LCD Panel 1024x768"
### Comment all HorizSync and VertSync values to use DDC:
HorizSync 31.5 - 48.5
VertRefresh 40.0 - 70.0
Option "dpms"
EndSection

Section "Device"
Identifier "Videocard0"
Driver "vesa"
EndSection

Section "Screen"
Identifier "Screen0"
Device "Videocard0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1024x768" "800x600" "640x480"
EndSubSection
EndSection

Making the best of VESA drivers in CentOS 5

Teaching in Edinburgh, on machines that flatly refuse to switch between CLI and GUI. Going into any of the CLI (CTRL_ALT_F1 - F6) is no problem, but restarting the X server or switching back from CLI gives random, hardly ever successful results.

Last week a couple of colleagues (Donald and Gary) were saying about dropping resolution, this week one of our techies (Stuart) found advice about vesa. Neither approach worked on its own, but put them together (albeit in a slightly modified way) and all is well.

If your GUI is working
Select:
System --> Administration --> Display (may need to put root's password if logged in as ordinary user)
Select Hardware tab
Configure "Monitor Type" to Generic LCD --> LCD Panel 1024 x 768
Configure "Video Card" to "vesa - Generic VESA-compliant video cards"
Do the OK three times.

I always check the config on RHEL/CentOS before restarting the GUI. Either look inside the configuration file (/etc/X11/xorg.conf, attached below) or check the System-->Administration-->Display-->Hardware settings (note that the vesa driver will be described as "Unknown video card").

To restart the GUI press CTRL-ALT-Backspace - all should be well.

If your GUI is NOT working

If the GUI is broken to the point you can't use the method above, you can hack the file directly, or enter the configuration screen from the command line. For that, log in as root on CLI (enter CLI with CRTL-ALT-F1), then enter:

# system-config-display

The system will use basic GUI settings to 'draw' the menus. Use the solution as provided above to complete the steps.

To start the GUI, the cleanest method I found is to 'recycle' runlevels: change into runlevel 3, then into runlevel 5.

# init 3
Several messages will be printed, when you see one fron "anaconda" hit enter. That will re-print the prompt. Now type:

# init 5

XWindows should start successfully!


===============================================
sample /etc/X11/xorg.conf using defaults for both the server and the monitor
===============================================
Section "ServerLayout"
Identifier "single head configuration"
Screen 0 "Screen0" 0 0
InputDevice "Keyboard0" "CoreKeyboard"
EndSection

Section "InputDevice"
Identifier "Keyboard0"
Driver "kbd"
Option "XkbModel" "pc105"
Option "XkbLayout" "gb"
EndSection

Section "Monitor"

### Comment all HorizSync and VertSync values to use DDC:
### Comment all HorizSync and VertSync values to use DDC:
Identifier "Monitor0"
ModelName "LCD Panel 1024x768"
### Comment all HorizSync and VertSync values to use DDC:
HorizSync 31.5 - 48.5
VertRefresh 40.0 - 70.0
Option "dpms"
EndSection

Section "Device"
Identifier "Videocard0"
Driver "vesa"
EndSection

Section "Screen"
Identifier "Screen0"
Device "Videocard0"
Monitor "Monitor0"
DefaultDepth 24
SubSection "Display"
Viewport 0 0
Depth 24
Modes "1024x768" "800x600" "640x480"
EndSubSection
EndSection