Cant start jack now

Hey again,

I had an issue with a parallel install of my self compiled version of jack along side my distro’s (Kubuntu Junty) version. I un-installed both the self compiled and distro installed versions, and then re-installed through my package manager (un-installed the way this page describes: ). Jack still wont start at all now. Any idea as to how I can fix this without formatting and starting over? This is what happens when I try to start jack via command line:

peter@PETER-PC:~$ /usr/bin/jackd -dalsa hw:0 -r48000 -p1024 -n3
no message buffer overruns
jackd 0.116.1
Copyright 2001-2005 Paul Davis and others.
This is free software, and you are welcome to redistribute it
under certain conditions; see the file COPYING for details

JACK compiled with System V SHM support.
cannot stat() /mnt/ramfs–prefix=/usr (No such file or directory)

cannot create server sockets
cannot create engine

I would very much appreciate help on this one…

     Thanks again!


maybe this error line is part of the solution :
cannot stat() /mnt/ramfs–prefix=/usr (No such file or directory)

how did you compiled jack ?

Thanks for the response!
I think I might have figured out the issue… When I compiled jack, I configured it with this command:
./configure --with-default-tmpdir=/mnt/ramfs–prefix=/usr

this made jack think that the default temp directory was /mnt/ramfs–prefix=/usr, instead of /mnt/ramfs which is what I wanted. For now, until I’m sure I configured jack correctly before install, I’m using my distro’s packages… But I guess I’ll try compiling JACK on a test guest OS before I install it in my main OS. Though I’m pretty sure this was the issue. I was just having problems removing all parts of the incorrectly configured jack! Now, jack runs well when starting through ardour. But when I try starting through qjackctl, I get about 40 xruns a second. Any ideas as to what that could be?

I’m guessing it’s still the default-tmpdir that bites you. Change that to /dev/shm like everyone else.

Then of course it depends on the jack settings; If you haven’t checked your limits.conf values and are running non-realtime you can’t run jack at a low latency level (though if you are running with -p1024 -n3 that shouldn’t be an issue).

OK, I finally fixed the xruns. I forgot I wasnt running my firepod as the audio device, and the latency was set set WAY too low for my on-board sound card… But, Its working well now, and I finally reconfigured and compiled jack to use /dev/shm as the temp directory. I found on my test machine I could get jack to run with /mnt/ramfs as the temp, but I had to run jack as root. Though, I don’t think that’s a very smart idea. Well, its fixed now. Now, off to compile a custom realtime kernel… Anywhere I can get tips on that? :confused:

If you use current JACK releases, there is NO reason to reset the tmpdir.

Ok Paul. Because I read a JACK install guide that said to set the temp to /mnt/ramfs instead of the default… It must have been an older guide. Thanks for the clarification.

Hi Guise…

Thank your for sharing this wonderful story. I find your post very informative.