There are two methods for installing RTXI on your computer:
- Booting off an Ubuntu-based RTXI Live CD, and
- Compiling a real-time Linux operating system and RTXI from scratch.
We suggest that users new to Linux start out with the Live CD. We have chosen Ubuntu since it is one of the more user-friendly distributions available and has an extensive online support community. If you choose to compile the OS yourself, you can choose any Linux distribution you like though there will be some minor differences in the installation steps. All Linux distributions are based on the same Linux “kernel,” which is the heart of the OS. The distributions differ in the utilities and libraries that are included by default, which leads to different desktop environments and applications. In general, you can expect to find an application for just about everything you need to do. For some users, the manual compilation will result in better real-time performance. The Live CD includes several benchmark tests that you can use to check your real-time performance and help you decide which installation method to use. Note that your performance results will likely be better with an actual hard drive installation of RTXI. If you choose to manually compile a real-time Linux kernel, you will probably want to install the default kernel using a Live CD anyways and we suggest that you read both sets of instructions.
Important: The current Live CDs are configured to handle processors with either one or two cores. If your system has more cores (eg. AMD Phenom X3/4, Intel Xeon Quadcore, Intel i5/i7), RTXI will not start off the Live CD. You will know if this is the issue by checking your kernel log:
$ dmesg
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[ 390.069252] RTAI[hal]: RTAI CONFIGURED WITH LESS THAN NUM ONLINE CPUS.
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You can fix this by reconfiguring RTAI with the correct number of cores or by starting Ubuntu with fewer cores. To reconfigure RTAI, see the notes for manual installation. To start Ubuntu with fewer cores, press “E” when you see the bootloader menu to edit the boot command. At the end of the line beginning with “boot” and probably also containing the flags “quiet splash”, add the flag maxcpus=”2″ or whatever number of cores you want to use. To boot with this modification, hit CTRL-X. This modification is not permanent so you would have to do this every time you restart the computer or manually edit your GRUB menu to add this flag.