Ubuntu 12.04 LTS - GRUB

Hardware: Asrock D1800B-ITX with SSD

I made a fresh install of Ubuntu 12 according to UpdatingTo2.6 and have the following issue:

Grub screen only appears on warm boot
On cold boot the Grub multi-boot does not appear. Pressing the hardware reset button for warm boot at the Ubuntu log-in screen the Grub screen appears and everything is fine.

Cannot load RTAI kernel in normal mode after updating GRUB
I changed the the GRUB file and comment out the 2 HIDDEN_TIMEOUT lines and updated GRUB with:
The Grub screen appears on warm and cold boot. However, I cannot load the RTAI kernel in normal boot load. On selecting rtai-686-pae a graphic screen appears with an error message (difficult to read something like graphic low resolution...). And I cannot continue from there.

Able to load RTAI kernel in recovery mode after updating GRUB
I can boot rtai-686-pae recovery mode. By selecting option 'resume' in the Recovery Menu everything is fine.

BTW - when RTAI is loaded, LinuxCNC is full functioning.

Current status
I made again a fresh install of Ubuntu 12 according to UpdatingTo2.6 and now would appreciate you receive some help to overcome my GRUB issue.

Hi

On selecting rtai-686-pae a graphic screen appears with an error message (difficult to read something like graphic low resolution...)

Without knowing what the error is, is hard to advise.

GRUB will often not show at all if there is only one entry in grub.cfg, and the Ubuntu installation probably does that, so your initial problems are not uncommon.

If the rtai kernel it will only start in recovery mode there is a problem, possibly with kernel modules and drivers, that can be got around when starting with a minimal set of modules.

Again without any error message, cannot help further.

Is there some reason you just don't install the Wheezy based distro?
Would simplify matters greatly.

regards

ArcEye wrote:

Is there some reason you just don't install the Wheezy based distro?

Thanx for taking your time. I thought saving some time with Ubuntu to integrate my CNC PC into my NAS which is running on AFP (my house is totally win-free). After fiddling around with my grub error for some hours, I decided to get the Wheezy distro up and running. Which I did now (error free installation) and take the pain to get the AFP protocol up and running.

I solved the login graphic issue with Ubuntu 12.04 LTS on my ASRock:

In BİOS the graphic card was set to PCIe , that needed to be changed to onboard (thanks to a hint in this forum). From there I started a fresh install. After all updates the following terminal commands were executed:

continued with LinuxCNC install instruction, until it says:
'Reboot, and make sure you boot into the rtai kernel'

Did not boot into the rtai kernel but first into the generic kernel. Ubuntu booted into text mode
Entered my user name and password and then:Booted into the generic kernel and voila the graphic logın screen
Reboot into rtai kernel and continued with LinuxCNC install instructions:
Now it works perfectly.

For those who are interested, here the Latency Test results after 2 hours with 3 videos in parallel, mp3 in a loop and all libre office programs loaded:

Asrock D1800B-ITX; 4GB RAM; SSD
Ubuntu 12.04 LTS
Servo max Jitter: 9500
Base max Jitter: 13000