Users for Jack Audio Connection Kit

The normal use of jack, which is envisioned as a single user utility: When a user wishes to make a recording, or edit a file starts with the user logging in, and load the jack daemon either manually, automatically or by launching a jack compatible application. This will provide the audio and midi interconnections between hardware and the various software needed for the job.

Another user can open another named jack session, but that session will not be able to access the sound card used by the first session.

Additionally, if the user closes his or her session all the jack infrastructure collapses. This is very problematic when the Jack session is used for real time applications like radio automation, streaming, Radio Studio-Transmitter Links, remote listeners, etc.

If the computer running jack reboots, the jack user must login before jack loads.

The work-around I have used is to create a special user that is exclusively runs for real time and audio processes. This user should be a member of the audio group, and should autologin, but have only those permissions that are needed to access the audio systems. (no sudo permission, for example). When jack needs to be adjusted, any other users on the machine should switch to the audio user and make the adjustments and then switch back to the normal user. See the post Ubuntu for 24/7 Operation for more information.

A good way to start jack in this paradyme is to make it a service and start at boot. This can also restart jack in case of a crash, and assure that its required support modules are in place before starting.