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Checked /lib/modules/2.6.32-122-rtai/_modules-builtin and sure enough ext4 support is built into the rtai kernel

So the installer should not have changed kernels, if that was the reason behind it, rather than some more subtle knock on effect.

The root of the problem is most likely to be the fiendishly complicated install scripting process for Ubuntu, onto which LinuxCNC has been grafted as
an extra few packages.
It may well have hard coded kernel choices for that file system when detected.

The bottom line is probably that ext4 is still being developed, breaks backwards compatibility and why would you need 16TB disk and
2TB file addressing capability for a CNC system that will install and run on < 2GB !?

Probably best to use ext2, or ext3 if you must, and avoid ext4 on LinuxCNC for now.

regards

It’s me again,

so, cancel my last. It had nothing to do with file system. At the last try I removed the network connection so the installation is a little faster. That was the reason that it worked. If I do the installation with removed network and ext4 it works as well. I tried it too, just to make sure that it’s not the file system.

But now I’m pretty happy. I finally got a system below 20000ns at the latency test. And the SSD increases the start up speed incredibly.

Regards,
Schuhmann

Hi

Glad you got usable latency, yes SSD's are great, silent and fast.

I think I preferred the previous installation problem hypothesis.
It was undesirable but at least understandable - sort of.

Can you post your new installer logs and I will attempt to find some factor which will give a proper install without a network connection, but which deletes LinuxCNC when you have one!

Don't hold your breath though, have a feeling this is going into the 'weird ubuntu s**t' file.
It must be some strange interaction with the specific hardware, or it would be coming up all the time.

regards

schuhmann wrote:[color=]Noob here.

I had the SAME ISSUE and resolved it by disconnecting the Ethernet on install! Sure glad I found it here!

My newly minted system:
D525MW (Bought based on recommendations on the forum - thank you, it's a cool board!)
4gb Ram (went w/ recommended kingston from the intel website, didn't want any issues)
Corsair Nova Series 2 30GB SSD (wanted smaller, but couldn't really find it, was nervous on the other recommendations)
ASUS DVD-RW

I also went w/ the 5i25/7i77 combo, but yet to get it configured and working.

To reiterate the issue:
When I ran off the CD everything worked great. Latency was good, was happy.

I installed, first from the desktop, when I rebooted and went to the applications menu, I didn't have a LinuxCNC folder like I had before when booting from the disk, but did have an Other folder, which had the LinuxCNC install manuals, but no LinuxCNC programs. Then re-installed from boot up, same thing.

From there I re-downloaded the install ISO and burned a new disk, thinking that might be the issue (but why??). Did the md5sum checking. Obviously same thing.

So, I tried to install LinuxCNC manually. The programs showed in the applications menu, but when I ran the latency test, nothing happened. Not even an error. So I ran LinuxCNC and I forget at what point, but rec'd an error:[/color]
"select kernel 2.6.32-122-rtai to run
choose kernel at boot menu."

After opening the boot menu, I ahve the following:
GNU GRUB version 1.98-1ubuntu13

Ubuntu, with Linux 2.6.32-41-generic pae
Ubuntu, with Linux 2.6.32-41-generic pae (recovery mode)
Memory test (memtest86+)
Memory test (memtest86+, serial console 115200)

Oh, then I monkeyed around w/ trying to install on ext2 about 3 or 4 times, didn't know where to mount the drive and was highly confused and I could not get it to work. I think one time the system was really slow....

Then I actually finished reading this thread, installed w/ out the ethernet attached - and viola! It ran like biscuits all night w/ latency around 10us (not stressed) and this morning I stressed it more to about 16/17us.

Next step is on to the 5i25/7i77. I'll remember to get power to the 7i77 to see the I/O, among other things like isocpus for the D525DW.

Thanks a Ton!
Mark

Hi

There was an update on this, thought it was on this thread and now I can't find it.

JT had the same problem on a new install and one of the developers came up with the answer, which was just a weird, the tipping point was memory over 3 GB.

In theory a 32 bit system should be able to use 4.xxGB but in practice it sees only 3.25GB

If you took one of your memory sticks out, you should find that the install would go through as it should, whether you had a network connection or not.

regards