Getting LinuxCNC

This section describes the recommended way to download and make a fresh install of LinuxCNC. There are also Alternate Install Methods for the adventurous. If you have an existing install that you want to upgrade, go to the Updating LinuxCNC section instead.

Note	LinuxCNC requires a special kernel with real-time extensions. There are three possibilities here: preempt-rt, RTAI or Xenomai. In addition there are two versions of LinuxCNC which work with these kernels. See the table below for details.

Fresh installs of LinuxCNC are most easily created using the Live/Install Image. This is a hybrid ISO filesystem image that can be written to a USB storage device or a DVD and used to boot a computer. At boot time you will be given a choice of booting the "Live" system (to run LinuxCNC without making any permanent changes to your computer) or booting the Installer (to install LinuxCNC and its operating system onto your computer’s hard drive).

The outline of the process looks like this:

Download the Live/Install Image.
Write the image to a USB storage device or DVD.
Boot the Live system to test out LinuxCNC.
Boot the Installer to install LinuxCNC.

1. Download the image

This section describes some methods for downloading the Live/Install Image.

1.1. Normal Download

For x86 PCs Download the Live/Install CD by clicking here:

http://www.linuxcnc.org/iso/linuxcnc-2.8.2-buster.iso

For the Raspberry Pi a complete SD card image is available here:

http://www.linuxcnc.org/iso/linuxcnc-2.8.1-pi4.zip (this will auto-update to 2.8.2 )

This can be installed using the normal Pi install process including with the Raspberry Pi Imager app.

This SD image is reported not to work with the Raspberry Pi4 8GB model. Note also that this version of the SD image limits available memory to 3GB as this is necessary to persuade it to run with both WiFi and USB working on some versions of the Pi. You can experiment with removing this limit by editing the config-rt.txt file in the boot directory. If you can’t boot after the change then the file can be edited back by mounting the SD card in a a different computer (maybe even a Pi with a USB card reader)

1.2. Download using zsync

zsync is a download application that efficiently resumes interrupted downloads and efficiently transfers large files with small modifications (if you have an older local copy). Use zsync if you have trouble downloading the image using the Normal Download method.

zsync in Linux

Install zsync using Synaptic or, by running the following in a terminal
```
sudo apt-get install zsync
```

Then run this command to download the iso to your computer

http://www.linuxcnc.org/iso/linuxcnc-2.8.2-buster.iso

zsync http://www.linuxcnc.org/iso/linuxcnc-2.8.1-pi4.zip.zsync

zsync in Windows

There is a Windows port of zsync. It works as a console application. It can be downloaded from:

https://www.assembla.com/spaces/zsync-windows/documents

1.3. Verify the image

(This step is unnecessary if you used zsync)

After downloading, verify the checksum of the image to ensure integrity.
```
md5sum linuxcnc-2.8.2-buster.iso
```
or
```
sha256sum linuxcnc-2.8.2-buster.iso
```

Then compare to these checksums

md5sum: 4496eae88a1d66f457205d0d5b69c3c2
sha256sum: 94a6dc7ef12fbdc0bafd9259ce36797a8b3410ad22e73c4ab57b8e937a924e1a

Verify md5sum on Windows or Mac

Windows and Mac OS X do not come with an md5sum program, but there are alternatives. More information can be found at: How To MD5SUM

2. Write the image to a bootable device

The Raspbery Pi image is a completes SD card image and should be written to an SD card in the normal way

The LinuxCNC Live/Install ISO Image is a hybrid ISO image which can be written directly to a USB storage device (flash drive) or a DVD and used to boot a computer. The image is too large to fit on a CD.

Writing the image to a USB storage device in Linux

Connect a USB storage device (for example a flash drive or thumb drive type device).
Determine the device file corresponding to the USB flash drive. This information can be found in the output of dmesg after connecting the device. /proc/partitions may also be helpful.
Use the dd command to write the image to your USB storage device. For example, if your storage device showed up as /dev/sde, then use this command:
```
dd if=linuxcnc-2.8.2-buster.iso of=/dev/sde
```

Writing the image to a USB storage device in Mac OSX

Open a terminal and type
```
diskutil list
```
Insert the USB and note the name of the new disk that appears, eg /dev/disk5
unmount the USB. The number found above should be substituted in place of the N
```
diskutil unmountDisk /dev/diskN
```
Transfer the data with dd, as for Linux above. Note that the disk name has an added "r" at the beginning
```
sudo dd if=/path-to.iso of=/dev/rdiskN bs=1m
```
Note that this may take a long time to complete and there will be no feedback during the process.

Writing the image to a DVD in Linux

Insert a blank DVD into your burner. A CD/DVD Creator or Choose Disc Type window will pop up. Close this, as we will not be using it.
Browse to the downloaded image in the file browser.
Right click on the ISO image file and choose Write to Disc.
Select the write speed. It is recommended that you write at the lowest possible speed.
Start the burning process.
If a choose a file name for the disc image window pops up, just pick OK.

Writing the image to a DVD in Windows

Download and install Infra Recorder, a free and open source image burning program: http://infrarecorder.org/
Insert a blank CD in the drive and select Do nothing or Cancel if an auto-run dialog pops up.
Open Infra Recorder, and select the Actions menu, then Burn image.

Writing the image to a DVD in Mac OSX

Download the .iso file
Right-click on the file in the Finder window and select "Burn to disc" (The option to burn to disc will only appear if the machine has an optical drive fitted or connected)

3. Testing LinuxCNC

With the USB storage device plugged in or the DVD in the DVD drive, shut down the computer then turn the computer back on. This will boot the computer from the Live/Install Image and choose the Live boot option.

Note	If the system does not boot from the DVD or USB stick it might be necessary to change the boot order in the PC BIOS.

Once the computer has booted up you can try out LinuxCNC without installing it. You can not create custom configurations or modify most system settings in a Live session, but you can (and should) run the latency test.

To try out LinuxCNC: from the Applications/CNC menu pick LinuxCNC. A dialog box will open from which you can choose one of many sample configurations. At this point it only really makes sense to pick a "sim" configuration. Some of the sample configurations include onscreen 3D simulated machines, look for "Vismach" to see these.

To see if your computer is suitable for software step pulse generation run the Latency Test as shown here.

At the time of writing the Live-Image is only available with the preempt-rt kernel and a matching LinuxCNC. On some hardware this might not offer good enough latency. There is an experimental version available using the RTAI realtime kernel which will often give better latency.

4. Installing LinuxCNC

To install LinuxCNC from the LiveCD select Install (Graphical) at bootup.

5. Updates to LinuxCNC

With the normal install the Update Manager will notify you of updates to LinuxCNC when you go on line and allow you to easily upgrade with no Linux knowledge needed. It is OK to upgrade everything except the operating system when asked to.

Warning

Do not upgrade the operating system if prompted to do so. You should accept OS updates however, especially security updates.

6. Install Problems

In rare cases you might have to reset the BIOS to default settings if during the Live CD install it cannot recognize the hard drive during the boot up.

7. Alternate Install Methods

The easiest, preferred way to install LinuxCNC is to use the Live/Install Image as described above. That method is as simple and reliable as we can make it, and is suitable for novice users and experienced users alike. However, this will typically replace any existing operating system.

In addition, for experienced users who are familiar with Debian system administration (finding install images, manipulating apt sources, changing kernel flavors, etc), new installs are supported on following platforms: ("amd64" means "64-bit", and is not specific to AMD processors, it will run on any 64-bit x86 system)

Distribution	Architecture	kernel	package name	Typical use
Debian Buster	amd64 & i386	Stock	linuxcnc-uspace	simulation only
Debian Buster	amd64 & armhf	preemp-rt	linuxcnc-uspace	machine control & simulation
Debian Buster	amd64	RTAI	linuxcnc	machine control (known issues)
Debian Jessie	amd64 & i386	Stock	linuxcnc-uspace	simulation only
Debian Wheezy	i386	RTAI	linuxcnc	machine control & simulation
Debian Wheezy	amd64 & i386	Preempt-RT	linuxcnc-uspace	machine control & simulation
Debian Wheezy	amd64 & i386	Stock	linuxcnc-uspace	simulation only
Ubuntu Precise	i386	RTAI	linuxcnc	machine control & simulation
Ubuntu Precise	amd64 & i386	Stock	linuxcnc-uspace	simulation only

Note	LinuxCNC v2.8 is not supported on Ubuntu Lucid or older.

Preempt-RT kernels

The Preempt-rt kernels are available for Debian from the regular debian.org archive. The preempt-rt kernel for RaspBerry Pi is available from the LinuxCNC repository. The package is called linux-image-rt-* Simply install the package in the same way as any other package from the Synaptic Package manager or with apt-get at the command-line.

RTAI Kernels

The RTAI kernels are available for download from the linuxcnc.org debian archive. The apt source is:

Debian Buster: deb http://linuxcnc.org buster base
Debian Wheezy: deb http://linuxcnc.org wheezy base
Ubuntu Precise: deb http://linuxcnc.org precise base

Note	Debian Wheezy and Ubuntu Precise are both extremely old, and are out of their support period. It is strongly advised not to use either for a new install, and to seriously consider upgrading an existing installation.

The Buster / RTAI package is only available on amd64, but there are very few surviving systems that can not run a 64-bit OS.

Warning

There are known issues with the 64-bit RTAI 5.2 kernel with this version of LinuxCNC. The system will occasionally lock solid. However, this has, so far, been seen only during system exit. While running the system appears to be stable. But should nevertheless be considered experimental at this point.

Note	If you decide to use the RTAI 5.2 kernel and see a problem outside the circumstances described above then please report it immediately to the project developers.

7.1. Installing on Debian Buster (with Preempt-RT kernel)

Install Debian Buster (Debian 10), amd64 version. You can download the installer here: https://www.debian.org/releases/buster/
After burning the iso and booting up if you don’t want Gnome desktop select Advanced Options > Alternative desktop environments and pick the one you like. Then select Install or Graphical Install.

Warning
Do not enter a root password, if you do sudo is disabled and you won’t be able to complete the following steps.
Run the following in a terminal to bring the machine up to date with the latest packages.
```
sudo apt-get update
sudo apt-get dist-upgrade
```

Install the Preempt-RT kernel and modules

sudo apt-get install linux-image-rt-amd64

Re-boot, and select the Linux 4.19.0-9-rt-amd64 kernel. This might be hidden in the "Advanced options for Debian Buster" sub-menu in Grub. When you log in, verify that `PREEMPT RT`is reported by the following command.
```
uname -v
```
Open Applications Menu > System > Synaptic Package Manager search for linux-image and right click on the original non-rt and select Mark for Complete Removal. Reboot. This is to force the system to boot from the RT kernel. If you prefer to retain both kernels then the other kernels need not be deleted, but grub boot configuration changes will be needed beyond the scope of this document.

Add the LinuxCNC Archive Signing Key to your apt keyring by running

sudo apt-key adv --keyserver hkp://keys.openpgp.org --recv-key 3cb9fd148f374fef

Add the apt repository:

 echo deb http://linuxcnc.org/ buster base 2.8-rtpreempt | sudo tee /etc/apt/sources.list.d/linuxcnc.list
 echo deb-src http://linuxcnc.org/ buster base 2.8-rtpreempt | sudo tee -a /etc/apt/sources.list.d/linuxcnc.list

Update the package list from linuxcnc.org
```
sudo apt-get update
```
Install uspace (a reboot may be required prior to installing uspace)
```
sudo apt-get install linuxcnc-uspace
```
Optionally you can install mesaflash if you are using a Mesa card.
```
sudo apt install mesaflash
```

7.2. Installing on Debian Buster (with experimental RTAI kernel)

Warning

This kernel has known stability problems. It appears to run reliably once LinuxCNC is loaded. However kernel panics have been seen at system shut-down.

This kernel and LinuxCNC version can be installed on top of the LiveDVD install, or alternatively on a fresh Install of Debian Buster 64-bit as described above
Add the LinuxCNC Archive Signing Key to your apt keyring (Not necessary if switching the realtime mode of a LinuxCNC Live-CD image)
```
sudo apt-key adv --keyserver hkp://keys.openpgp.org --recv-key 3cb9fd148f374fef
```

Add the apt repository:

 echo deb http://linuxcnc.org/ buster base 2.8-rt | sudo tee /etc/apt/sources.list.d/linuxcnc.list
 echo deb-src http://linuxcnc.org/ buster base 2.8-rt | sudo tee -a /etc/apt/sources.list.d/linuxcnc.list

Update the package list from linuxcnc.org
```
sudo apt-get update
```
Install the new realtime kernel, RTAI and the rtai version of linuxcnc
```
sudo apt-get install linuxcnc
```

Reboot the machine, ensuring that the system boots from the new 4.19.195-rtai kernel.

7.3. Installing on Raspbian 10

Download a stock Raspbian image to an SD card and install in the usual way
Boot the Pi and open a terminal

Add the LinuxCNC Archive Signing Key to your apt keyring

sudo apt-key adv --keyserver hkp://keys.openpgp.org --recv-key 3cb9fd148f374fef

Add the apt repository:

 echo deb http://linuxcnc.org/ buster base 2.8-rtpreempt | sudo tee /etc/apt/sources.list.d/linuxcnc.list

Update the package list from linuxcnc.org
```
sudo apt-get update
```

install the realtime kernel

sudo apt-get install linux-image-4.19.71-rt24-v7l+

Install linuxcnc (a reboot may be required prior to installing)
```
sudo apt-get install linuxcnc-uspace
```

7.4. Installing on Ubuntu Precise

Install Ubuntu Precise 12.04 x86 (32-bit). Any flavor should work (regular Ubuntu, Xubuntu, Lubuntu, etc). 64-bit (AMD64) is currently not supported. You can download the installer here: http://releases.ubuntu.com/precise/ Note the warnings that this release is out of support. But it is a way to install LinuxCNC with a well-tested RTAI kernel.
Run the following to bring the machine up to date with the latest packages in Ubuntu Precise.
```
sudo apt-get update
sudo apt-get dist-upgrade
```

Add the LinuxCNC Archive Signing Key to your apt keyring by running

sudo apt-key adv --keyserver hkp://keys.openpgp.org --recv-key 3cb9fd148f374fef

Add a new apt source

sudo add-apt-repository "deb http://linuxcnc.org/ precise base 2.8-rt"

Fetch the package list from linuxcnc.org.
```
sudo apt-get update
```

Install the RTAI kernel and modules by running

sudo apt-get install linux-image-3.4-9-rtai-686-pae rtai-modules-3.4-9-rtai-686-pae

If you want to be able to build LinuxCNC from source using the git repo, also run
```
sudo apt-get install linux-headers-3.4-9-rtai-686-pae
```
Reboot, and make sure you boot into the rtai kernel. When you log in, verify that the kernel name is 3.4-9-rtai-686-pae.
```
uname -r
```
Run
```
sudo apt-get install linuxcnc
```