[linux-audio-user] jackd fails to start: cannot create shm segment /jack-shm-registry (No such file or directory)

[Jack O'Quin]

This is beyond me.  Are you running devfs by any chance?

I'm copying this message to the jackit-devel list.  Maybe someone
there knows what this problem is.

"Ivica Bukvic" <ico at fuse.net> writes:

> /dev/shm exists right after install, but there is no entry in the
> /etc/fstab.
> 
> The funny thing about the /dev/shm dir is that you cannot remove or
> modify even as root. It's default creation date is Dec.31 1969 until it
> gets mounted, at which point it converts itself to the appropriate date.
> 
> I had to manually add the below included line to fstab:
> 
> none /dev/shm tmpfs defaults 0 0
> 
> and had to mount it manually in order for the jack's ./configure to
> report that it has successfully found POSIX memory sharing. Yet, the
> error persists when the newly compiled jackd is started:
> 
> key for /tmp/jack/shm/jack-shm-registry is 0x6a0bdb99
> cannot create shm segment /jack-shm-registry (No such file or directory)
> cannot create engine
> 
> Should I simply revert to the older version of Jack until this stuff is
> sorted out?
> 
> BTW, configure does revert to the other style of shared memory stuff
> (System V shm) if it does not find POSIX one, but even if I compile that
> one, I still end up with the same error/results.
> 
> Thanks for your help!
> 
> Ico
> 
> 
> > -----Original Message-----
> > From: linux-audio-user-admin at music.columbia.edu
> [mailto:linux-audio-user-
> > admin at music.columbia.edu] On Behalf Of Jack O'Quin
> > Sent: Friday, April 18, 2003 3:42 PM
> > To: linux-audio-user at music.columbia.edu
> > Subject: Re: [linux-audio-user] jackd fails to start: cannot create
> shm
> > segment /jack-shm-registry (No such file or directory)
> > 
> > "Ivica Bukvic" <ico at fuse.net> writes:
> > 
> > > Hmm., I guess I was rejoicing prematurely...
> > >
> > > I added /dev/shm into fstab:
> > >
> > > none /dev/shm tmpfs defaults 0 0
> > >
> > > recompiled CVS jack (configure finds shm stuff ok)
> > >
> > > started jack and the same thingy happens:
> > >
> > > jackd -d alsa -d hw:0
> > > jackd 0.68.0
> > > Copyright 2001-2003 Paul Davis and others.
> > > jackd comes with ABSOLUTELY NO WARRANTY
> > > This is free software, and you are welcome to redistribute it
> > > under certain conditions; see the file COPYING for details
> > >
> > > key for /tmp/jack/shm/jack-shm-registry is 0x6a0bdb99
> > > cannot create shm segment /jack-shm-registry (No such file or
> directory)
> > > cannot create engine
> > >
> > > I guess I am back to square one.
> > >
> > > In addition, I forgot to mention one important issue with my other
> > > machine (where Jack works), and that is that it was updated from
> mdk9.0,
> > > while this one was a clean install. After two clean installs on two
> > > different machines, I noticed that neither had the shm entry in
> fstab,
> > > which obviously nullifies the possibility that it was a faulty
> install
> > > in the first place.
> > 
> > Apparently, the POSIX shared memory implementation is not a standard
> > part of most Linux distributions.  That's a shame.
> > 
> > > Again, any help is greatly appreciated! Sincerely,
> > 
> > Does the directory /dev/shm exist?  If not, "mkdir /dev/shm" (as
> root).
> > Then mount /dev/shm, and try starting jackd again.
> > 
> > What does "grep shm /etc/fstab" say?
> > 
> > Sorry this is such a hassle.

-- 
  Jack O'Quin
  Austin, Texas, USA