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Re: cdda2wav not copying right? (long)



Hey,

> When I said it was moving too fast, I meant the CD-ROM was reading the
> data faster then the system could keep up with, which is basically
> what you are saying. :-)

Ah... Sorry about that... :)

> Some of the time the system was idle (other then ripping) and a couple
> of times I was switching between workspaces, but not doing much. The
> only activity is disk I/O. The SCSI LED is lit solid! I've moved large
> amounts of data between disks and not seen the bus this saturated. The
> CPU is idle other then seti@home, I've tried doing it without
> seti@home running and was able to produce a skip.

Hmmm. If you're getting skips without any other system activity,
then it might be a problem with SCSI throughput...here's a section
from the cdda2wav README:

Recommendations for higher throughput on Linux SCSI systems
===========================================================

Higher throughput will give better chances for non-interrupted
sampling. This should avoid typical interruption errors (cracklings
at buffer boundaries).

1. Increase SG_BIG_BUFF to (128*1024) in /usr/src/linux/include/scsi/sg.h
   (and recompile your kernel and boot it :-).
NOTE: Some kernel configurations will lead to 'out of kernel memory' errors.
   If you encounter this message regularly, better leave SG_BIG_BUFF at
   32768.

1a.There is a patch for multiple sg device access under Linux. It uses
   up to 128 K buffer for each device. See here:
ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/alpha/sg*

2. Ensure your harddisk has write cache enabled (For SCSI hard disks I
   switched it on with the scsiinfo program from tsx-11.mit.edu), but
   enable this only if it is correctly working ;-)

This has boosted the throughput of cdda2wav considerably.

Good luck!

Zonker
--
Joe 'Zonker' Brockmeier
jbrockmeier@earthlink.net
ICQ: 43599611
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