Date: Mon, 9 Jun 1997 20:26:22 +0200 (MET DST) From: Wilko Bulte <wilko@yedi.iaf.nl> To: gibbs@plutotech.com (Justin T. Gibbs) Cc: gibbs@plutotech.com, asami@cs.berkeley.edu, scsi@FreeBSD.ORG Subject: Re: 3940uw with long cables Message-ID: <199706091826.UAA00957@yedi.iaf.nl> In-Reply-To: <199706082134.PAA16830@pluto.plutotech.com> from "Justin T. Gibbs" at Jun 8, 97 04:33:46 pm
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As Justin T. Gibbs wrote... > >> 1) Having equal distances between all devices is sometimes more > >> important than total bus length since the varying RC constants > >> can cause strange signal skew conditions if the lengths aren't > >> matched. > >In addition to this: don't use both the internal and the external > >connector of a SCSI adapter (assuming the internal & external > >connector are on the same bus). The differences in external versus > >internal (flat)cable are also no-good. > If you get quality external cables, along with high quatlity > connectors, this need not be an issue. When dealing with cabling, And high quality terminators. > it is the impedance of the cable and its length that are important, > not its "external" or "internal" nature. I would only recommend Exactly, but matching internal and external cable impedance might be a problem. It is hard to determine impedances, and at least well beyond the scope of the average SCSI user. I think the following is valid: - if it works: fine - if it does not: try external and internal buses on seperate hostadapters. Wilko _ ____________________________________________________________________ | / o / / _ Bulte email: wilko@yedi.iaf.nl - Arnhem, The Netherlands |/|/ / / /( (_) Do, or do not. There is no 'try' - Yoda --------------------------------------------------------------------------
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