Date: Fri, 25 Oct 2002 12:43:45 -0500 From: "Jack L. Stone" <jackstone@sage-one.net> To: freebsd-questions@freebsd.org Subject: Re: UDMA limited to 33 - resolution Message-ID: <3.0.5.32.20021025124345.01b1e400@mail.sage-one.net> In-Reply-To: <3.0.5.32.20021025121912.01b1e400@mail.sage-one.net> References: <20021025094521.B58366-100000@q.closedsrc.org> <20021023161917.H11289-100000@babelfish.pursued-with.net>
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At 12:19 PM 10.25.2002 -0500, you wrote: >At 09:47 AM 10.25.2002 -0700, Linh Pham wrote: >>On 2002-10-23, Kevin Stevens scribbled: >> >># However, it *is* correct that all devices on a UDMA channel must support >># UDMA, so yes, the above is a problem. I don't recall if all devices must >># also be the same UDMA speed (66/100/133) or not, bbelieve that is true >># too. This is not a BSD issue, it is part of the UDMA spec. >> >>IIRC- >> >>The channel will run at the speed of the slowest device, meaning that if >>you have a drive that is capable of ATA/66 and a drive capable of ATA/33 >>on the same channel, then the channel will run at ATA/33. >> >>If you have a drive at ATA/100 and a drive that is only capable of PIO4, >>then the speed of the channel will be knocked down to either PIO4 or >>ATA/33 (the latter will only occur if the PIO4 drive is also capable to >>running at ATA/33, just without DMA). >> >>-- >> >>Linh Pham lplist@closedsrc.org > >Well, then what does the jumper settings on modern drives for "Master with >non-ATA compatible sleave" mean in regard to the above speed limits...??? > Ooops! That should be "...slave .... NOT sleave..."" Best regards, Jack L. Stone, Administrator SageOne Net http://www.sage-one.net jackstone@sage-one.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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