[pulseaudio-discuss] some-alpha-numerics:default-source

[Lennart Poettering]

On Tue, 09.06.09 20:52, mike _ (arizonagroovejet at gmail.com) wrote:

> So what, if anything, is that alphanumeric string based upon? Is there
> a way to determine the value of that string for the current session,
> thus enabling deletion of the files that have names begining with it?

It's the (D-Bus) machine id (/var/lib/dbus/machine-id) . We use it to
make sure that we store device-specific information only
per-machine. The D-Bus machine id is always available, unique to the
machine and much more useful than hostnames in times where hostnames
can change dynamically during runtime.

If this ID changes across reboots on your machine then your OS
very broken, since it appears to regenerate the DBus machine id each
time. It's not supposed to do that.

And yes, if you log in from a different machine then you'll get a new
set of config files, that's the whole idea. It's a bit hard for PA
however to figure out when you sold a machine or lost access to a
machine, so cleaning this up automatically is practially impossible.

Also, note that all released versions of PA used gdbm as the
device/stream/card database format. However gdbm creates perversly
large files on NFS because it uses the device's native block size,
which can be quite large. [1]

PA in git now uses Samba's tdb format, which doesn't suffer by this
braindeadness, so the files should be much smaller. 

Lennart

[1] This could actually be fixed in the old code I guess. One could
    patch PA so that gdbm_open()'s second parameter is fixed to 1024
    or so.

-- 
Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4