April 2008 – Update – I’ve modified the instructions so that EMC2 can now be run as a user.
April 2008 – Update – Fixed some mistakes.

The following instructions will describe how to install the latest version of EMC2/LinuxCNC in Ubuntu 7.10 Gutsy Gibbon.

Axis User Interface

Why would you want to do this? You would do this if you don’t want to wait for new .deb files from the EMC2 team or you want to install EMC2 in the latest version of Ubuntu to take advantage of all the new features. The alternative is to use the Ubuntu 6.06 LTS live CD, install and then either stick with the software versions supplied or upgrade to the latest versions (such as device drivers, Gnome, Xorg, etc.), which is a big task itself.

Why would you not want to do this? I don’t recommend following these steps if you are unfamiliar with Linux and the shell/command prompt. It will either be a great learning experience or a very frustrating waste of time.

I am sure these steps can be simplified and improved, however they were created from many hours of experimenting and following dead-ends. I wanted to try and give you exactly what I ended up using, rather than an optimization. For example I’m sure that not all the reboots are needed, but they only take 60 seconds on my PC anyway.

These steps should work on a stock installation of Ubuntu 7.10, however I don’t make any claims that they will work for anyone else. If the software didn’t install correctly and the motors go crazy and move something that destroys your house, don’t blame me – these instructions are provided “as is” and without any warranty. Use at your own risk. If you spot a mistake please let me know and I will update the instructions.

Where you see “andy” replace with your own username, unless it is also “andy”. :)

‘$’ represents the prompt, to show you where the start of lines are. Don’t enter this, just what follows.

The process looks like this:

Get a vanilla kernel and patch it with RTAI support.
Test kernel.
Build and test RTAI modules.
Build EMC2.

Enable universe repository in /etc/apt/sources.list. Open a terminal window and then:

$ sudo apt-get update
$ sudo apt-get install build-essential libncurses5-dev kernel-package
$ cd /usr/src
$ sudo wget -c http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.22.tar.gz
$ sudo tar xzvf linux-2.6.22.tar.gz
$ sudo mv linux-2.6.22 linux-vanilla-2.6.22
$ sudo ln -s linux-vanilla-2.6.22 linux
$ cd linux
$ sudo cp /boot/config-2.6.22-14-generic .config
$ sudo make menuconfig

At this point a menu will appear. Make the following choices:

Loadable module support > Module versioning support (N)
Loadable module support > Set version information on all module symbols (N)*
Processor type and features > Preemption model > Preemptible kernel (low latency desktop)
Processor type and features > Symmetric multi-processor support (N)**
Processor type and features > Local APIC support on uniprocessors (N)
Power management options (ACPI, APM) > ACPI support (N)
Power management options (ACPI, APM) > APM BIOS support (N)
Power management options (ACPI, APM) > CPU frequency scaling (N)
Kernel hacking > Compile the kernel with frame pointers (N)

* only if you have it in the menu
** only if your PC is not dual or quad core

Download rtai-3.6-test1.tar.bz2 from www.rtai.org (click on “RTAI Repository” link) to the desktop.

$ cd /home/andy/Desktop
$ bunzip2 rtai-3.6-test1.tar.bz2
$ tar xvf rtai-3.6-test1.tar

$ cd /usr/src/linux
$ sudo patch -p1 < /home/andy/Desktop/rtai-3.6-test1/base/arch/i386/patches/hal-linux-2.6.22-i386-1.10-09.patch

$ sudo make-kpkg --initrd --revision=1 --append-to-version=-realtime kernel_image kernel_headers

Some questions may appear which need to be answered (answer Y to any others that appear):

Interrupt pipeline – Y
Interrupt pipeline maintain backwards compatibility – Y
Interrupt pipeline debug – N

Now go and do something else for a while. On my P4 1.6GHz PC the kernel took 2 hours and 50 minutes to build.

$ cd ..
$ sudo dpkg -i linux-image-2.6.22-realtime_1_i386.deb
$ sudo nano -w /boot/grub/menu.lst

Find the line that looks like:


and change it to:


If your PC already dual-boots (for example Ubuntu and Windows) then the hiddemenu is probably already commented out (using the ‘#’).

Save and exit nano.

Reboot and choose the realtime kernel from Grub menu.


$ uname -a

and you should get something like:

Linux pepper 2.6.22-realtime #1 PREEMPT Sun Oct 28 10:54:43 MST 2007 i686 GNU/Linux

Make sure everything works ok (browsing, editing files, etc.)

Now we need to build the RTAI modules. This has to be done while running the realtime kernel we just built and booted into.

$ cd /home/andy/Desktop/rtai-3.6-test1
$ make menuconfig

Again a menu appears. Make the following selections:

Machine (x86) > Number of CPUs (enter the number you have here)

Exit and save configuration

$ make
$ sudo make install

Reboot back into the realtime kernel.

$ cd /usr/realtime/bin
$ sudo nano -w rtai-load

Change the first line from:




and save. Then:

$ sudo nano -w /etc/init.d/create-rtai-devices.sh


mknod -m 666 /dev/rtai_shm c 10 254
for n in `seq 0 9`
mknod -m 666 $f c 150 $n

Save. Then:

$ sudo chmod 755 /etc/init.d/create-rtai-devices.sh
$ sudo update-rc.d create-rtai-devices.sh defaults

Reboot back into the realtime kernel.

Then test the RTAI support with:

$ cd /usr/realtime/testsuite/user/latency
$ sudo ./run
$ cd /usr/realtime/testsuite/user/preempt
$ sudo ./run
$ cd /usr/realtime/testsuite/user/switches
$ sudo ./run
$ cd /usr/realtime/testsuite/kern/latency
$ sudo ./run
$ cd /usr/realtime/testsuite/kern/preempt
$ sudo ./run
$ cd /usr/realtime/testsuite/kern/switches
$ sudo ./run

These tests spit out lots of numbers. The thing we are looking for here are kernel panics, system crashes, etc. Also make sure there are no overruns in the tests that display an overruns column.

If you get something like:

insmod: error inserting '/usr/realtime/modules/rtai_hal.ko': -1
Operation not permitted

then try:

$ sudo nano -w /boot/grub/menu.lst

and find the kernel line for the realtime kernel. Add “lapic” to the end of it and reboot, then run the tests again. For example:

kernel /boot/vmlinuz-2.6.22-realtime root=UUID=45d21232-cf0d-cc3d-87ce-8453214d7a6f ro quiet splash vga=794 lapic

Once you have the real time tests working continue with:

$ sudo nano -w /etc/modprobe.d/emc2


install parport_pc /bin/true

Save then reboot back into the realtime kernel. Now to build and install EMC2.

$ sudo apt-get install python python-imaging python-imaging-tk python-numarray python-dev
$ sudo apt-get install tcl8.4-dev tk8.4-dev yapps2
$ sudo apt-get install libgtk2.0-dev libpth-dev libreadline5-dev libxmu-dev libxaw7-dev libglu1-mesa libglu1-mesa-dev libgl1-mesa-dev
$ sudo apt-get install pciutils-dev bwidget cvs latex2html preview-latex-style libaiksaurus-1.2-0c2a libgnomeprintui2.2-dev
$ sudo apt-get install imagemagick lyx

$ cd /usr/src
$ sudo dpkg -i linux-headers-2.6.22-realtime_1_i386.deb
$ cd ~
$ cvs -z5 -d:ext:anon@cvs.linuxcnc.org:/cvs co emc2
$ cd emc2/src
$ ./configure --with-realtime=/usr/realtime --with-kernel-headers=/usr/src/linux-headers-2.6.22-realtime
$ make
$ sudo make install

$ sudo nano -w /etc/security/limits.conf

Add the line:

* hard memlock 20480

Save and reboot into the realtime kernel.

To run EMC:

$ /usr/local/bin/emc

A window should appear with a choice of configurations. Choose Axis -> Sim and the Axis window should open. Congratulations EMC2 is now running!

Note that when running the realtime kernel the computer may not power itself off when the shutdown option is chosen. This is because the power management options have been disabled in the kernel. On my PC I wait a couple of minutes after the screen goes blank then press the power button on the front of the PC. This turns it off.

EMC2 Configuration Window