DD not working--SUCCESS!

Alan Cox alan at lxorguk.ukuu.org.uk
Fri Aug 31 21:14:39 UTC 2007


On Fri, 31 Aug 2007 12:50:42 -0500
Les Mikesell <lesmikesell at gmail.com> wrote:

> Mikkel L. Ellertson wrote:
> 
> > dd should not use lots of CPU time. The bottleneck is disk access
> > speed. Depending on the drivers used, and some tweaking, the system
> > may be spending a lot of time in the disk driver routines doing
> > basically nothing.
> 
> CPU use will depend on your disk controller.  IDE controllers have a lot 
> of CPU overhead for seeks/positioning even if DMA is used for the data 
> transfer - that's why people still use SCSI for busy servers.

Thankfully no longer true as of SATA providing your controller does AHCI
or similar and the drives support NCQ

Alan




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