Messages in this thread | | | Date | Tue, 10 Oct 2000 20:59:30 +0200 | From | Vojtech Pavlik <> | Subject | Re: Incorrect UDMA timing on VIA vt82c596b |
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On Tue, Oct 10, 2000 at 01:42:51PM -0400, Mark Hahn wrote: > > > > Btw, reading the ATA/ATAPI-6 specs I think UDMA66 should work on a > > > > setup where would be just one drive and a really short, 40-wire cable > > > > without problems as well. I've even seen systems shipped like that. > > > > > > uh, what part of the spec leads you to that conclusion? > > > I've haven't seen a draft more recent than ~1h2000, but > > > they've been unambiguous about absolutely requiring > > > 80-conductors for >= ata66, and that two-connector cables > > > must be 5<=l<=18, and three-connector cables 10<=l<=18. > > > > ATA/ATAPI-6 draft rev. 0a, page 14 (sheet 28 of 404), table 2, row 4, > > column 1, plus comment 4 in the same table. > > guess I should get a more up-to-date draft! > > > And from the engineering point of view, it seems reasonable, too. > > noise/crosstalk-wise, sure. does the new spec also permit > a min length less than 5" between host and dev1?
The spec talks about three types of connection - "40-wire assembly", "80-wire assembly", both being three-connector cables with the limitations you cite. Plus it talks about a "direct point-to-point connection" for a single device case. There isn't any minimum length specified for that case. This may be some relict in the spec, though.
-- Vojtech Pavlik SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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