[nas] re: Sound dropouts using ALSA and NAS on Linux

[David Morano]

> The problem is intermittent dropouts in the playing of a wav file.
> They seem to occur at the same points in the sound, i.e., if you
> play the sound again you are likely to hear the same pattern of
> dropouts.

I also get sound dropouts on Solaris 2.6 on SPARC hardware.  I am using
NAS 1.4.  The dropouts appear to be the worst when the client is on the
same machine as the server but the dropouts can be observed with a
remote client also to a lessor extent.  They seem to show up the most
when playing straight 44100 sps stereo PCM files (at least that makes
sense being as its about the most data the server will see compared to
lower sample rates).

Further, it appears that the problem is the worst for servers on
Sun Ultra SPARC boxes as compared with an older SPARC-20.

Here is the Ultra SPARC server information :

> Version Number:         2.2
> Vendor:                 NAS Release 1.4 - Sun unified dda 
>                         (running on SUNW,CS4231)
> Vendor Release:         1

Here is a SPARC-20 server information :

> Version Number:         2.2
> Vendor:                 NAS Release 1.4 - Sun unified dda 
>                         (running on SUNW,dbri)
> Vendor Release:         1

The Sparc-20 box is an old dual CPU 150 Hz Hyper SPARC while the Ultra
SPARC (which causes a much worse dropout problem) is a dual CPU 200 MHz
Ultra SPARC-1.

Here is another funny thing to consider (maybe it is not related)
but why does :

$ audial 123456789

cause what seems to be dropouts and runs the sound of the digits
together ?  This problem only occurs on the Ultra-SPARC box.  It might
be unrelated to the general dropout problem but it is curious that NAS
on Ultra SPARC seems to perform the worst in every way even though it
has more CPU available than older Sparcs !

Thanks for any information or help,
Dave Morano
morano at computer.org