On Wed, Apr 2, 2008 at 6:24 PM, Sam Clemens
Greg Freemyer wrote:
<snip>
3) Strangely, most drives do tie 300 MB/sec to the Sata-2 functions set, so if you use the 150 MB/sec throttle jumper to slow down the drive, you loose the NCQ function.
Why deliberately throttle down a drive? They're slow enough already. And the SAS/SATA negotiation standard specifies that the controller and the disk are supposed to negotiate their speed.
One of the standard troubleshooting techniques on lkml-ide is to throttle down the drive. A surprising number of times it fixes the problem. And the 300 MB/sec Seagates I've been buying all come with the jumper installed. (ie. they are throttled when shipped.) FYI: We buy about 20 to 50 drives a month for our lab depending on what is going on. First thing we do is wipe them. (dd if=/dev/zero of=/dev/sdb). We occasionally try wiping with and without the jumper installed. So far no difference, but we tend to use PCI based controllers, so the PCI bus could be our real throttle. Greg -- Greg Freemyer Litigation Triage Solutions Specialist http://www.linkedin.com/in/gregfreemyer First 99 Days Litigation White Paper - http://www.norcrossgroup.com/forms/whitepapers/99%20Days%20whitepaper.pdf The Norcross Group The Intersection of Evidence & Technology http://www.norcrossgroup.com -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org