Date: Sat, 7 Jun 1997 20:31:18 +0200 (MET DST) From: Wilko Bulte <wilko@yedi.iaf.nl> To: gibbs@plutotech.com (Justin T. Gibbs) Cc: asami@cs.berkeley.edu, scsi@FreeBSD.ORG Subject: Re: 3940uw with long cables Message-ID: <199706071831.UAA00806@yedi.iaf.nl> In-Reply-To: <199706070047.SAA07204@pluto.plutotech.com> from "Justin T. Gibbs" at Jun 6, 97 07:45:54 pm
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As Justin T. Gibbs wrote... > Perhaps. There are a few important things to keep in mind when > tuning the bus length. > > 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. > 6) Honor the 6m and 3m bus length limits. 6m is the longest for 10MHz > and 3m is the longest for 20MHz single ended SCSI. This assumes > proper stub/gap matching, so real life buses may need to be shorter. Hm. The company I work for (==DEC) uses the rule that a single ended F10 (10MHz) bus can be a max of 3 meters. Wilko _ ____________________________________________________________________ | / o / / _ Bulte email: wilko@yedi.iaf.nl - Arnhem, The Netherlands |/|/ / / /( (_) Do, or do not. There is no 'try' - Yoda --------------------------------------------------------------------------
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