Date: Sat, 21 Jul 2001 13:24:41 -0400 From: Bill Moran <wmoran@iowna.com> To: User & Ian Patrick Thomas <ipthomas_77@yahoo.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: How to change UDMA mode on ata drives Message-ID: <3B59BAD9.76F2C4C5@iowna.com> References: <3B5987B1.C5310BB0@iowna.com> <20010721114445.C5115@localhost> <3B59A707.F4D60AD0@iowna.com> <20010721121247.E5115@localhost>
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User & Ian Patrick Thomas wrote: > > As it was put forth by Bill Moran on Sat, Jul 21, 2001 at 12:00:07PM -0400... > > The only options I have through sysctl are hw.atamodes, and hw.ata.ata_dma > > both of which only allow turning DMA on and off. I would like to leave it > > on, but force the controller to use UDMA4 (ata66) instead of UDMA5 (ata100) > > > > Is there a method for this, or is it an on/off proposition? > > I havn't found one that allows you to specify 66 instead of 100. If > you wanted to throttle down to 33 then you could use the 40 cable, but both > 66 and 100 use the 80 cable, correct? The driver uses the maximum > achievable speed. Could it be that the source to the driver needs to be > tweaked? Actually, according to the spec sheets for this drive, you need an 80 pin for anything ata33 or faster. Thus plugging in a 40pin will slow the thing down to 16MB/sec. Not what I want, but if it proves reliable, it will be one step closer to having this problem solved! On a side note ... I'm a little lost with this 80 pin thing. How does an 80 conductor cable with a 40 pin connector on each end do anything more than a 40 conductor cable? Seems a little odd to me. -Bill -- It may be that true happiness is nothing more than the ability to *always* know the right thing to say at the right time, whereas true misery is the state of perpetually saying to oneself, "What I *should* have said was..." To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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