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[[cha:getting-linuxcnc]]

= Getting LinuxCNC

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

NOTE: To operate machinery 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. However for code
testing and simulation it is possible to run the linuxcnc-uspace application on a stock kernel. 

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.

== Download the image

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

=== Normal Download

Software for LinuxCNC to download is presented on the project's
https://linuxcnc.org/downloads/[Downloads page].
Most users will aim for the disk image for Intel/AMD PCs, the URL
will resemble https://www.linuxcnc.org/iso/linuxcnc_2.9.4-amd64.hybrid.iso.

For the Raspberry Pi, multiple images are provided to address
differences between the RPi4 and RPi5.

NOTE: Do not use the regular Raspbian distribution for LinuxCNC that may have shipped with
your RPi starter kit - that will not have the real-time kernel and you cannot
migrate from Raspbian to Debian's kernel image.

=== 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,Normal Download>>
method.

.zsync in Linux

. Install zsync using Synaptic or, by running the following in a <<faq:terminal,terminal>>
+
----
sudo apt-get install zsync
----
. Then run this command to download the iso to your computer
+
----
zsync https://www.linuxcnc.org/iso/linuxcnc_2.9.4-amd64.hybrid.iso
----

.zsync in Windows

There is a Windows port of zsync.
It works as a console application and can be downloaded from
https://www.assembla.com/spaces/zsync-windows/documents .

=== Verify the image

(This step is unnecessary if you used zsync)

. After downloading, verify the checksum of the image to ensure integrity.

----
md5sum linuxcnc-2.9.4-amd64.iso
----

or

----
sha256sum linuxcnc-2.9.4-amd64.iso
----
. Then compare to these checksums

-----
amd64 (PC)
md5sum: 1815aceaac0e7861747aa34d61846e79
sha256sum: 08b3f59233e47c91cf1c9a85c41df48542c97b134efefa7446d3060c9a3e644b
arm64 (Pi)
md5sum: 4547e8a72433efb033f0a5cf166a5cd2
sha256sum: ff3ba9b8dfb93baf1e2232746655f8521a606bc0fab91bffc04ba74cc3be6bf0 
-----

.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:
https://help.ubuntu.com/community/HowToMD5SUM[How To MD5SUM]

== Write the image to a bootable device

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.

=== Raspberry Pi Image

The Raspbery Pi image is a completes SD card image and should be
written to an SD card with the [Raspberry Pi Imager App](https://www.raspberrypi.com/software/).

=== AMD-64 (x86-64, PC) Image using GUI tools

Download and install [Balena Etcher](https://etcher.balena.io/#download-etcher)
(Linux, Windows, Mac) and write the downloaded image to a USB drive.

If your image fails to boot then please also try https://rufus.ie/[Rufus].
It looks more complicated but seems to be more compatible with various BIOSes.

=== Command line - 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_2.9.4-amd64.hybrid.iso of=/dev/sde
-----

=== Command line - MacOS

. 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 substitued 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 begining
+
-----
sudo dd if=linuxcnc_2.9.4-amd64.hybrid.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)

== 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 may 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 <<sec:latency-test,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.

== Installing LinuxCNC

To install LinuxCNC from the Live CD select 'Install (Graphical)' at bootup.

== Updates to LinuxCNC (((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.

== 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.

== 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.
If you have files on the target PC that you want to keep, then use one of the methods described in this section.

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)

[options="header"]
|===
| Distribution    | Architecture  | Kernel     | Package name    | Typical use
| Debian Bookworm | amd64 & arm64 | preempt-rt | linuxcnc-uspace | machine control & simulation
| Debian Bookworm | amd64         | RTAI       | linuxcnc        | machine control
| Debian Bullseye | amd64         | preempt-rt | linuxcnc-uspace | machine control & simulation
| Debian Buster   | amd64 & arm64 | preempt-rt | linuxcnc-uspace | machine control & simulation
| Debian Buster   | amd64         | RTAI       | linuxcnc        | machine control
| Any             | Any           | Stock      | linuxcnc-uspace | simulation ONLY
|===

NOTE: LinuxCNC v2.9 is not supported on Debian 9 or older.

.Preempt-RT kernels

The Preempt-rt kernels are available for Debian from the regular debian.org archive.
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 Bookworm: `deb http://linuxcnc.org bookworm base`
* Debian Bullseye: `deb http://linuxcnc.org bullseye base`
* Debian Buster: `deb http://linuxcnc.org buster base`

LinuxCNC and the RTAI kernel are now only available for 64-bit OSes but
there are very few surviving systems that can not run a 64-bit OS.

=== Installing on Debian Bookworm (with Preempt-RT kernel)

. Install Debian Bookworm (Debian 12), amd64 version.
  You can download the installer here:
  https://www.debian.org/distrib/

. 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 <<faq:terminal,terminal>> to bring the machine up to
  date with the latest packages.
+
----
sudo apt-get update
sudo apt-get dist-upgrade
----

NOTE: It is possible to download a version of LinuxCNC directly from Debian
but this will install an old pre-release version, and is not recommended
at this time.

. Install the Preempt-RT kernel and modules
+
----
sudo apt-get install linux-image-rt-amd64

----

. Re-boot, and select the Linux 6.1.0-10-rt-amd64 kernel. The exact
kernel version might be different, look for the "-rt" suffix. This might be
hidden in the "Advanced options for Debian Bookworm" 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 downloading
  [the LinuxCNC installer script](https://www.linuxcnc.org/linuxcnc-install.sh)
  You will need to make the script executable to run it:
----
chmod +x linuxcnc-install.sh
----
  Then you can run the installer:
----
sudo ./linuxcnc-install.sh
----

[[cha:Installing-RTAI]]
=== Installing on Debian Bookworm (with experimental RTAI kernel)

. This kernel and LinuxCNC version can be installed on top of the Live DVD
  install, or alternatively on a fresh Install of Debian Bookworm 64-bit
  as described above.
. You can add the LinuxCNC Archive signing key and repository information
  by downloading and running the installer script as decribed above. If
  an RTAI kernel is detected it will stop before installing any packages. 

. 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 5.4.258-rtai
kernel.

=== Installing on Raspbian 12

Don't do that. The latencies are too bad with the default kernel and the PREEMPT_RT (the RT is important) kernel of Debian does not boot on the Pi (as of 1/2024).
Please refer to the images provided online.
You can create them yourself following the scripts provided https://github.com/rodw-au/rpi-img-builder-lcnc[online].

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