Date: Fri, 25 Oct 2002 09:47:51 -0700 (PDT) From: Linh Pham <lplist@closedsrc.org> To: Kevin Stevens <Kevin_Stevens@pursued-with.net> Cc: "Jack L. Stone" <jackstone@sage-one.net>, lewiz <purple@lewiz.info>, Steve Warwick <ukla@attbi.com>, <freebsd-questions@FreeBSD.ORG> Subject: Re: UDMA limited to 33 - resolution Message-ID: <20021025094521.B58366-100000@q.closedsrc.org> In-Reply-To: <20021023161917.H11289-100000@babelfish.pursued-with.net>
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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 Webmaster and FreeBSD Geek http://closedsrc.org closedsrc.org Every solution breeds new problems To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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