Complete HOW-TO Linux Mint 18.1 32/64 RTAI or PREEMPT with RIP install or deb

4.8.2-rt2 is the name you chose for your preempt-rt kernel?

If so, then "Posix non-realtime" doesn't really add up.

Thanks Andy!

4.9.4-rt2 is the version printed. I think he just did not click on the fully preemptive option in the makexmenu .conf step.

I have not made that particular mistake ... yet

I guess we will have to see.. IF Linuxcnc was configured as a sim... then would it still print using non realtime?

CAUTION: You MUST at the minimum select "Fully Preemptable Kernel" in the "Processor Types and Features" section. You can use the search function to find this easy.

Having run command "make xconfig", after awhile Linux/x86 4.9.4 Kernel Configuration windows popped up and I wasn't able to fine quoted instruction. Any hints, before I move on?

Sorry, found!!!

I can suggest two options to install/remove the kernel you have already installed.

Boot into your default -generic kernel and remove the 4.9.4-rt2 kernel prior to installing the .deb for your [new] 4.9.4-rt2 kernel.

or

Install the new 4.9.4-rt2 .deb kernel then remove the other 4.9.4-rt2 [old] kernel.

I would suggest the first one.

probamo,

How did it go? Are you up and running yet?

Copying an already compiled kernel and Linuxcnc to another computer and installing it works on Mint and Lubuntu.
Tested it yesterday on Lubuntu, did that on Mint several times before. Took about 50 minutes from start to finish.
Nice ! Saves a lot of time when working with a lot of computers. Have over 20 in the work shop.
Thank you very much, CncNoob.

I went well. Just to avoid any confusion, let me in short explain the approach.

Previously I tried to get linuxcnc in LM18.1 with RTAI kernel without success. LM18.1 was installed on my Thinkpad X60 laptop. Therefore, I tried compiling kernel 4.9.4 RT on my desktop computer running with Ubuntu 16.04 (the same base for LM18.1).

Compiling went well, therefore I did installation on it. In addition compiling of linuxcnc 2.8 passed well, hence I installed it accordingly. Since I did not check "Full Preemptable Kernel" I had a huge figures in Latency Test. Then I started again compiling kernel, this time corrected. In the mean time, on my laptop, I did compiling of linuxcnc 2.7.8.

As soon as files for kernel and linuxcnc 2.7 were made I restarted comps. By pressing down left Shift, entering GRUB loader, I was selecting the latest generic kernels. Once operating system were up, I removed previously installed RT and RTAI kernels. Then installed new made. In Ubuntu no problems found, and in LM18.1 no problems found even kernel files were created in Ubuntu platform. Great! Again comps restarted.

Entering GRUB loader I was not able to select RT kernel neither on desktop, nor laptop, simply they are no in listed kernels. Decided to start comps with the up most kernels, in Terminal, by typing "uname -r" and "uname -a" I found both comps are in 4.9.4 rt2 kernel. Then in laptop I installed linuxcnc 2.7.8 and was able to run sim and real machine (files created by stepconfig) without any issue. Knowing laptop is not good candidate for CNC operation, it would be used only as simulator to the "real world". Contrary, my desktop computer with linuxcnc 2.8 installed run without any issue in simulation. Reported message before I got, regarding parallel port missing is true, I have not any parallel port on motherboard, not even any place where I could plugin an external parallel port card. Therefore, desktop would be used as simulator only for linuxcnc 2.8.

Coming back to the listed kernels. Running "grub-customizer" in Terminal, still I cannot see RT kernels installed at any of comps. Why? I don't know.

The important is, kernel made in one platform, could be installed in the other. Linuxcnc compiled in one platform, could be installed in the other.

cncnoob, tommy, andy Once again thanks for nice instruction and support.
Dejan (probamo)

Great Glad you have it working!

To update the listings - The kernel install should have updaed the initramfs listings. To do this manually please try this:


This invokes the update script to "update" all available kernels on the system.

you could also try to update grub


Let me know how it goes please.

EDIT: How is your latency now?

None of them brings any benefit to me. Still not listed kernel. Regrading latency:
- desktop starts at 25, easy going to 38, unstable goes to 110
- laptop start at 52, goes to 68, unstable goes to 305