Re: ATAPI CD-R lags system to hell burning in DAO mode; but not in TAO

[Andrew Morton]

Aaron Lehmann wrote:
> 
> I've got a Teac CD-W524E 24x CD-R writer, and ever since I got it
> several months ago I have had the somewhat annoying issue that burning
> a cd Disc-At-Once makes the system unusable during the burn. The X
> cursor jerks, repaints take forever, etc. This problem doesn't occur
> when burning Track-At-Once - I'm unable to notice any significant
> increase in system latency when using that mode.
> 

This is presumably because the machine is full of memory which
is dirty against a slooow device.

You can work around this by reducing the dirty memory thresholds:

akpm-1:/home/akpm> cat /proc/sys/vm/bdflush
30      64      64      256     30000   3000    60      0       0

Make the "30" and "60" smaller.  10 and 20 perhaps.

Better: change the application to fsync() the data every few
megabytes, or open O_SYNC.

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