Date: Sat, 21 Jul 2001 16:45:09 -0400 From: User & Ian Patrick Thomas <ipthomas_77@yahoo.com> To: Bill Moran <wmoran@iowna.com> Cc: freebsd-questions@freebsd.org Subject: Re: How to change UDMA mode on ata drives Message-ID: <20010721164509.A6316@localhost> In-Reply-To: <3B59BAD9.76F2C4C5@iowna.com>; from wmoran@iowna.com on Sat, Jul 21, 2001 at 01:24:41PM -0400 References: <3B5987B1.C5310BB0@iowna.com> <20010721114445.C5115@localhost> <3B59A707.F4D60AD0@iowna.com> <20010721121247.E5115@localhost> <3B59BAD9.76F2C4C5@iowna.com>
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As it was put forth by Bill Moran on Sat, Jul 21, 2001 at 01:24:41PM -0400... > 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 > I'm not sure which one to believe, the FreeBSD man page, or the drive's specs. The man ata says 66 and above for the 80 conductor cable. I'm using a 40 conductor now and dmesg has my drive at 33 UDMA.(It's a Maxtor). As far as how it works, I guess searching online is the best route. Ian > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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