Subject: Re: [linux-audio-user] Laptop + Multiface = Easy?
From: Mark Knecht (markknecht_AT_comcast.net)
Date: Mon Sep 13 2004 - 04:20:21 EEST
On Sun, 2004-09-12 at 17:00, Dan Harper wrote:
<SNIP>
> Last Saturday I recorded a band in the studio. In total we did 8 analog
> in, 5 analog out, 2 SPDIF out.
>
> In a live recording sense, it worked sort of OK. The only thing I had
> trouble with were random xruns that started to appear half way through
> the day.
>
<SNIP>
> - xruns are $%*^& (really annoying). I still get them every now and
> again, but I may have tracked it down to using a reiserfs filesystem.
> I've now switched to ext2 and there are less xruns now.
<SNIP>
Dan,
I wonder how what you were using for an audio drive and how full it
was?
I did a two night session using Pro Tools back in late April. The
equivalent of an xrun in that environment is an 'Interrupts held off too
long' message. I didn't receive a single one in 5 hours of recording. A
couple of months later, using the same laptop, the same 002 Rack, and
the same disk drive we blew 3 takes early in the evening due to
interrupts being held off.
Looking at my drive I saw it was about 90% full. As this is a FAT32
drive that implied more fragmentation. I then deleted about 20% of the
drive that was backed up elsewhere, did a quick drive optimization, and
15 minutes later we started recording again. We recorded for 2 1/2 hours
without a problem.
While none of this directly applicable to what you are experiencing,
when I read your note it seemed similar enough to go ahead and write
back. It might not only be the type of files system, but also where on
the drive you are writing. It's not always that well known, but most
drives are 30-50% slower at the far end of the drive. Most drives are
speed rated when they are empty.
Good luck fixing your problems. Sounds like you're going down a good
path.
BTW - On guy recently built a 7200RPM 200GB 1394b S800 drive and
tested it under Linux. He got 55MB/s. On the same machine I thin he was
getting about 45MB/s from his 10K RPM SCSI drive. There are options...
Cheers,
Mark
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