Installing LinuxCNC 2.8.4 on Ubuntu 22.04 LTS with Real Time Kernel

Hi! Ubuntu has made their real time kernel for 22.04 generally available. Are there any plans to make Linux CNC 2.8 (or newer) compatible with it?

Here's my kernel info:

$ uname -rvmpio
5.15.0-1032-realtime #35-Ubuntu SMP PREEMPT_RT Tue Jan 24 11:45:03 UTC 2023 x86_64 x86_64 x86_64 GNU/Linux

I downloaded the debian package for linuxcnc-uspace and tried to install it, but it doesn't work. Here's the output:

$ sudo apt install ./linuxcnc-uspace_2.8.4_amd64.deb
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
You might want to run 'apt --fix-broken install' to correct these.
The following packages have unmet dependencies:
 linuxcnc-uspace : Depends: libboost-python1.67.0 but it is not installable
                   Depends: libpython2.7 (>= 2.7) but it is not installed
                   Depends: libreadline5 (>= 5.2) but it is not installable
                   Depends: python2.7-tk
                   Depends: python2.7-numpy but it is not installable or
                            python-numpy but it is not installable
                   Depends: python2.7-imaging but it is not installable or
                            python-imaging but it is not installable or
                            python-pil but it is not installable
                   Depends: python2.7-imaging-tk but it is not installable or
                            python-imaging-tk but it is not installable or
                            python-pil.imagetk but it is not installable
                   Depends: python-gtksourceview2 but it is not installable
                   Depends: python-gst-1.0 but it is not installable
                   Depends: python-xlib but it is not installable
                   Depends: python-gtkglext1 but it is not installable
                   Depends: python-configobj but it is not installable

I tried 'sudo apt --fix-broken install', but all it does is remove linuxcnc-uspace from the dpkg database.

Just looking at the first dependency, 22.04 only has libboost-python1.74.0 available, but 2.8.4 requires 1.67.0

So, will a later version of LinuxCNC support Ubuntu 22.04 RT or should I look at switching to Debian? Thanks

Linuxcnc 2.8 uses Python 2.7 which has since been dropped from the Linux distros as its obsolete. Later versions of Linuxcnc (2.9 and above) use Python 3.x Its not surprising you had problems.

If you must use Ubuntu, use their Kinetic release as linuxcnc-uspace is included in their repositories.

The PC is a desktop from Sherline and came with Ubuntu 20.04 with the realtime patches. I finally got a WiFi adapter so I can apply updates. I had seen where Ubuntu Pro would let you apply the Canonical real time patch to 22.04 LTS and so I thought I try it out. I haven’t programmed in Python in several years so I didn’t realize 2.x had been dropped.

I’ll give 22.10 (Kinetic) a shot and if I can’t get that to work, I’ll wipe and reload 20.04 from Sherline and be more careful with updates.

Thanks for the help!

If you are converting from a version of linuxcnc before 2.8, there have been some changes. It should get updated when you first run it, but if it doesn't you might need to make some changes.

Just so everybody is aware, linuxcnc-uspace does not install on Ubuntu 24.04 LTS due to dependency errors caused by irrelevant Python version issues. Python 3.13 can run Python 3.10 code just fine!

Wi-Fi adapters may increase latency.

Be careful!

In general, it is best to physically remove as much unnecessary hardware as possible, then Install Ubuntu.

You may also install LinuxCNC using the official Debian ISO. It works great.

However, I personally hate Debian.

I believe that Debian is the least user friendly, most confusing, most non-intuitive OS ever made.

But that takes work.

Ubuntu is just great out of the box (okay, Ubuntu has its issues too).

Also, disabling hardware is a great way to reduce latency, but stupid Debian makes it almaost impossible to blacklist kernel modules.

Down with XFCE!

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