Xenomai realtime kernel (i386)

Choose and copy and paste the following into a shell to install your kernel:

sudo apt-get install linux-image-xenomai.x86-686-pae      # i386

Note	There are only Xenomai kernels for Wheezy and Jessie not Stretch or Buster

RT-PREEMPT realtime kernel (i386)

Debian Wheezy has an older RT-PREEMPT kernel

This is installable with

sudo apt-get install linux-image-3.2.0-4-rt-686-pae
or just
sudo apt-get install linux-image-rt-686-pae

Debian Jessie has now been backported to the Debian Stretch rt-preempt kernel

You need to add a line to your /etc/apt/sources.list file

sudo echo "deb http://ftp.uk.debian.org/debian/ jessie-backports main contrib non-free" \
 >> /etc/apt/sources.list

(You can change uk for whatever your geographic mirror location)

Then update apt and pull the kernel

sudo apt-get update
sudo apt-get install linux-image-rt-686-pae

Debian Stretch and Buster repos contain rt-preempt kernels

Update apt and pull the kernel

sudo apt-get update
sudo apt-get install linux-image-rt-686-pae

If you want to build your own kernel, see the Developing section for more details.