Date: Fri, 28 Nov 1997 14:55:14 -0500 (EST) From: jack <jack@diamond.xtalwind.net> To: David Greenman <dg@root.com> Cc: freebsd-isp@freebsd.org Subject: Re: Adaptec 2940 and FreeBSD 2.2.2-RELEASE Message-ID: <Pine.BSF.3.96.971128144614.1044B-100000@germanium.xtalwind.net> In-Reply-To: <199711281853.KAA18707@implode.root.com>
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On Fri, 28 Nov 1997, David Greenman wrote: > >On Fri, 28 Nov 1997, Jeff Lynch wrote: > > > >> The only problems I've had with 2940UWs on fbsd2.1.5-2.2.1 have occurred > >> when we mix wide/narrow devices on the host adapter or attach a narrow > >> (of course) external tape drive. Leaving the bus all wide or all narrow > >> and all internal has never given us problems. > > > >The servers we have that keep blowing up have only a single internal DAT > >on the narrow bus and a single internal UW HDD on the wide bus. It most > >common for a tape error to lock up the machine, but they also lock up > >with the same symptoms when no backups are being done. > > Hmmm...Do you have a narrow->wide converter than has termination for the > upper (wide) data bits? I had a lot of problems here with using a narrow > drive on a wide controller until Justin pointed out that the upper bits have > to be terminated. I fixed the problem by putting a wide device at the end > of the same cable that the narrow device was on (thus providing full wide > termination). The trick, I think, is to have the last wide and the last narrow devices terminated. On the controller do not terminate the narrow but do terminate the wide. Works out something like this: W---------------C I O D N E---------------T N---------------r-------N A o A R l R R---------------r-------R Not quite up to Terry's ansi art but you get the idea. :} Note that you can only use two of internal narrow, internal wide, and external. Using all three results in a 'Y' effect on the narrow side of the scsi chain. -------------------------------------------------------------------------- Jack O'Neill Finger jacko@diamond.xtalwind.net or jack@xtalwind.net http://www.xtalwind.net/~jacko/pubpgp.html #include <std_disclaimers.h> for my PGP key. PGP Key fingerprint = F6 C4 E6 D4 2F 15 A7 67 FD 09 E9 3C 5F CC EB CD --------------------------------------------------------------------------
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