Installing Planet CCRMA on Fedora 7

The Planet CCRMA package collection for Fedora 7 (i386 or x86_64 architectures) resides in a Yum (Yellowdog Updater Modified) repository that can be accessed through the Internet.

You will need to have a reasonably fast network connection to the world to install Planet CCRMA by connecting directly to its repository or one of its mirrors.

Installing Planet CCRMA is easy. You will be guided through the install process in the following pages.

Installing Fedora

The first step is to install Fedora 7 itself. You can download cdrom or dvd images from the main Fedora site at RedHat or one of its mirrors. Or you can use the re-spins from the Fedora Unity project which include more up to date packages and will save you a lot of downloads later.

Regardless of which dvd or cdrom you use, make sure you upgrade to the latest security and functionality upgrades before proceeding. Run this (as root) from a terminal:

yum upgrade

It could take a long time to download and install all the upgrades...

Installing the Planet CCRMA package signature

All packages in the Fedora 7 Planet CCRMA repositories are signed (that is, rpm will know if the package has been altered if you have the proper signature installed).

First install the GPG signature key for Planet CCRMA, if you are connected to the Internet just do:

rpm --import http://ccrma.stanford.edu/planetccrma/RPM-GPG-KEY.planetccrma.txt

Adding the Planet CCRMA repositories

You now need to add the proper urls to your Yum configuration files so that it can access the Planet CCRMA repositories.

rpm -Uvh http://ccrma.stanford.edu/planetccrma/mirror/fedora/linux/planetccrma/7/i386/planetccrma-repo-1.0-3.fc7.ccrma.noarch.rpm

This will install configuration files for Yum that will enable it to access the Planet CCRMA repositories.

Installing the low latency kernel

Planet CCRMA provides a version of the Linux kernel that includes the realtime preemption patches by Ingo Molnar. While the stock Fedora kernels will also work for non-critical audio work the realtime preemption patches are pretty much a requirement for reliable behavior at low latencies.

Before installing the Planet CCRMA kernel you should edit this yum plugin configuration file and disable it:

/etc/yum/pluginconf.d/installonlyn.conf

(by default this yum plugin will force yum to keep only the latest two kernels you install and will erase any older kernels. That's not usually what you want if you are trying out kernels - you always want to have the original kernel around in case something goes wrong).

In the latest updates of yum the functionality of this plugin has moved to the core yum implementation, if that is the case you will need to edit /etc/yum.conf and add this line to its end:

installonly_limit=0

NOTE: we are not installing the kernels directly. There's a reason. The planetccrma-core package is empty but it requires all the actual packages needed, and with the proper versions. The core packages include the patched kernel itself, a patched version of PAM that has access to realtime scheduling and memory locking for all users (that is, anyone can hang the machine - but you need this for good low latency performance) and a startup script that reorders the priority of the interrupt handling to favor the sound cards.

So, go ahead and install the Planet realtime kernel:

yum install planetccrma-core

If this is an update, that is, you have previously installed the jack-audio-connection-kit that is part of the Fedora repository, you will need to edit /etc/security/limits.conf to modify the permissions for realtime scheduling and memory locking (which are set by the Fedora Jack package to much more conservative values than what Planet CCRMA needs).

So, edit /etc/security/limits.conf and see what you have for the values of ``rtprio'', ``nice'' and ``memlock'' parameters, if the lines where those parameters appear start with anything other than ``*'' then you need to change the file. Change those lines to be:

* - rtprio 99
* - nice -10
* - memlock 4000000

(this will give any user access to realtime scheduling and memory locking - not just a group - and the maximum usable priority will be 99 instead of - last time I checked - 20).

Testing the new kernel

At this point you can cross your fingers and reboot the machine. At the grub prompt press any key to access the boot menu and then select the kernel you want to try (the Planet CCRMA kernel, if it was the last kernel installed, should be the default).

If at any time you want or need to change the default boot kernel you can edit the /boot/grub/grub.conf file and changing the ``default='' line to point to the kernel you want to boot by default. Kernels are zero base indexed, ``0'' being the first in the list of kernels that follows the default line. Depending on how many kernels you just installed, and which one you want to boot by default, the ``default='' line should read ``0'' or ``1''.

Installing applications

You are done with the hard stuff. At this point you have a machine that has a low latency kernel and it is booting happily (hopefully).

Now you have to install the actual applications and start having fun!

One way to do this is to just go ahead and browse through the web pages of the Planet CCRMA repoview (or here for the Planet CCRMA Core components).

I'm providing a meta package (an empty package that requieres other packages) so that you can install all major apps in one yum incantation. If you want to do that then type this in a terminal (as root):

yum install planetccrma-apps

Good luck in your explorations of the musical world hosted on Linux! Be patient, if you are coming from other operating systems there is a new world to learn and discover. Getting to know it is rewarding but it will take time.