LinuxCNC running on Ubuntu 18.04 updated to kernel 4.18.12 with Preempt RT

jferguson wrote: Have you done it?

Many times.

Can you install debian packages? There is a set here:
www.linuxcnc.org/temp
If you install 18.04 from the standard .iso, then install the kernel deb above, then the rtai application, then the rest, you stand a good chance of ending up with a working LinuxCNC installation.

I apologize if this should be obvious to me, but if I'm now running 4.15.0-74-generic, should the kernel source and patch I download be the same rev?.

I'll look at the debian packages.

FWIW, the last time I did a kernel (re)compile was SunOS 4.1.4, and I can't remember why, probably to get rid of functions I didn't need in the hope of getting performance improved.

thanks for helping here.

john

jferguson wrote: I apologize if this should be obvious to me, but if I'm now running 4.15.0-74-generic, should the kernel source and patch I download be the same rev?.

It seems not to matter that much. I think any 4.x should be OK.
You can try it, at least. Install the kernel deb (sudo dpkg --install linux-image.....deb ) and then pick it in the grub menu at boot time.
If it doesn't work, reboot and select the original one.

(the new kernel probably hides under "advanced options"

thanks. I'll let you know how this works out.

Hi Andy,
I did the deb installation and it seems to have worked. I get the rtai kernel report when I do uname -r. It also doesn't load the broadcom wifi driver but does do ethernet. It displays at a fixed 1080X768 +/- (theres a fire somewhere in our building and i'm sitting in front waiting for the firemen to give us an all clear)

It looks like it will be fine for running linuxcnc which is all I'd use that instance for. and it does work with the nvidia card which I use for other things on the other 18.04 instance for cad and other things.

so now all i have to do is open the archives and compile linuxcnc. I'll use the russian instructions unless you can suggest something you like better.
and thanks,
john

There are precompiled LinuxCNC v2.8 .debs on that directory too. No need to compile.

yippee. now to unscrew my multi-boot grub installation - done it before-should be able to remember. Linux install packages ought to have a toggle which asks if you want to do new grub. but not to worry - I'll grok it.

Installation seems to be a success. I get latency numbers which look good, and the software appears to work. Need to do the same thing at the machine in the shop. And load up my machine specific configs.

My thanks to the folks who set up the debs so to make this so easy.

and to you Andy for pointing me to them.

Cheers.

john

I did the installation on the machine at the shop, had the problem with screen resolution and fixed that with a grub modification. I tried loading one of my config files, but got the error about changes in HAL and INI files and the routine did not fix the problem. Then I tried using stepconf to modify an existing config. I loaded one of my existing configs in stepconf, stepped through the pages and saved, and that now runs.
i can't remember if my configs were hand-edited so will compare the ini files to make sure that everything I thought i needed is still there.
I haven't tried cutting a new pcb, but the machine moves according to the code so it seems good.

One change I would like to make which is apparently an improvement with LinuCNC 2.8 is the display showing the work-piece and the tool paths is now covered with G-Code status. I had liked having only X,Y, Z and velocity. How can I fix this?

And lastly, this whole thing was so easy and the result so much better than trying to run 10.04, why isn't it the prime recommendation for folks wanting to run a newer flavor of Ubuntu?

I should add that I was unable to get the Nvidia driver to actually work. It says it's using it in the Software Update routine, but "nvidia settings" says it isn't. No big deal as resolution I'm getting 1078x768 is plenty good. Screen display is a bit jumpy though which I had thought might be cured if I COULD get nvidia driver to load.

jferguson wrote:
One change I would like to make which is apparently an improvement with LinuCNC 2.8 is the display showing the work-piece and the tool paths is now covered with G-Code status. I had liked having only X,Y, Z and velocity. How can I fix this?

On the View menu click on "show offsets"