Date: Tue, 16 Aug 2005 19:13:14 -0500 From: Mark Kane <mark@mkproductions.org> To: jason <jason@ec.rr.com> Cc: freebsd-questions@freebsd.org Subject: Re: How to Force UDMA100 Mode on Boot? Message-ID: <4302811A.3010601@mkproductions.org> In-Reply-To: <43026F5B.4010705@ec.rr.com> References: <430128F1.9@mkproductions.org> <43013444.8080808@ec.rr.com> <43014383.1040400@mkproductions.org> <43026F5B.4010705@ec.rr.com>
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jason wrote: > I checked the links and saw no dmesg or drive models for all drives. I > can tell you UDMA 133 was not an official spec, a least at first. It > was a maxtor only thing, and not all chipsets handled it. Basically > maxtor tightened the timings on the ide cable signals to squence extra > data. If you have new and old drives, plus different brands I would not > expect to run at 133 speeds. I don't care to look it up now, but you > may want to find out if any other drive manufactures support the 133 > spec today. Also there are load and signal degregation issues with to > think about with longer cables. If you have a full tower case with the > longest cables you can buy you won't get max speeds even at the 133 > setting. If you know someone whos works in a pc rpair shop you could > ask them what cable length does to drive speeds. I am told if you want > to copy drives for customers you want to get a good cable, but only with > 1 device per cable and get it as short as possible. A 2 inch cable will > dramatically shorten the time to copy whole drives compared to a 16 inch > cable. Well now I can't even get two drives on the same channel to mount together. If one is mounted and I try to mount the other one on the same channel, the other gets immediate DMA_READ problems and then failures. This is trying two brand new drives with brand new cables. If I eliminate one of the drives and run one on each channel, they all work fine together. I'm not sure if that rc.local trick that was suggested would work now. I don't know if drives get mounted before rc.local would get executed or not. Going to have to bring back my thread on the errors. -Mark
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