Date: Fri, 25 Oct 2002 12:19:12 -0500 From: "Jack L. Stone" <jackstone@sage-one.net> To: Linh Pham <lplist@closedsrc.org>, Kevin Stevens <Kevin_Stevens@pursued-with.net> Cc: lewiz <purple@lewiz.info>, Steve Warwick <ukla@attbi.com>, <freebsd-questions@FreeBSD.ORG> Subject: Re: UDMA limited to 33 - resolution Message-ID: <3.0.5.32.20021025121912.01b1e400@mail.sage-one.net> In-Reply-To: <20021025094521.B58366-100000@q.closedsrc.org> References: <20021023161917.H11289-100000@babelfish.pursued-with.net>
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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...??? 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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