[linux-audio-user] The trouble with disks

Mark Knecht mknecht at controlnet.com
Fri Dec 19 13:47:20 EST 2003

> Yeah, there was a pretty regular series of spikes in white. None of them
> were closer than, say 10-15% of the total distance.

On the surface of it that sound pretty safe.

> 0.91.3, I've been updating from CVS every few days since about 3 weeks
> ago. That was just before 0.90 IIRC.

I think the point that Jan made in another thread somewhere on this tmpfs
subject (and I may be wrong here so don't take this as gospel) is that since
Jack is now compiled to use a specific FIFO location, if you change the
location in fstab then you *must* recompile Jack to point it to the new
location. I'm just being extra careful in asking you if you actually did
that recompile.

Some command like 'jackd --version' will tell you where it's pointing, and
you can look at the directory and see if the files are there.

> > 4) What command are you generally using to start Jack?
> In a terminal. jackd -R -d alsa -d hw:0 -p 256 -n 3

Looks at least reasonable. Are you getting the same problems as both user
and root?

You could also add the verbose option to watch for xruns:

jackd -v -R alsa ...

> Same hard drive, same SCSI controller, same sound card. Only difference
> from that point of view is that the SCSI controller used to be in a
> 64bit PCI slot. But I can't see that making a huge difference because
> the throughput from one drive wouldn't even begin to get close to the
> throughput limits of a 32 bit slot. Well, I'm guessing here.

No, you are right, and others are getting many more tracks than you without
64-bit slots, so unless the SCSI controller itself has an issue being in a
32-bit slot I don't think this is it.

> Only at 48k - that's all I've got.
Because that's all the sound card will do? It won't run at 44.1K?

An idea? Have you tried running an 'all software' experiment, or 'almost all
software', to understand whether it's really the disk causing this? What
happens if you load up a CD with Alsaplayer and play it, and then patch in
some Jack clients like freqtreak, tapiir, etc., multiple times to create a
lot of Jack traffic, but little or no hard disk traffic? You can create an
arbitrarily complicated setup to maybe explore whether the problem is with
Jack, or possibly with your motherboard, it's memory usage, other
applications that are running. If these work right, but then a disk based
operation fails, you have more info....


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