Date: Fri, 29 Jan 1999 15:20:59 -0800 From: ONE-MO <onemo@jps.net> To: Wes Santee <wes@bogon.net> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: 2nd SCSI drive not detected. Why? Message-ID: <36B2425B.4416F26D@jps.net> References: <199901292318.PAA02399@bogon.net>
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Wes Santee wrote: > And ONE-MO proclaimed... > > Do you have proper termination of the 68pin channel. Wide-SCSI is > > extremely sensitive to this and I find many people using > > Fast-SCSI without a terminator don't notice problems until they > > introduce a Wide drive into the mix. > > > > FWIW I have a 2940UW with two Ultra-Wide SCA drives using SCA to 68pin > > converter. I couldn't access the second drive unless I enabled > > termination on the second drives SCA converter. > > > > Thanks for the tips. I made sure that termination is active on both > drives since they are at either end of the SCSI bus. However, I noted > that the Wide drive has 4 termination settings (5 if you include no > termination). I'll do some research to make sure I've got the right > *kind* of termination set, just to make sure. > > Still, even with improper termination, if the SCSI bus can see the drive, > shouldn't the OS be able to? Improper termination would seem to lead to > instability, but I would still expect the OS to see it's there since > the SCSI adapter can see it. I'm just speculating here, however. > > Cheers, > -Wes No necessarily. It's the OS and application level software that is going to be sensitive to transmission timings and such. The BIOS simply polls the channel and waits fotr a response from each ID/LUN. Although termination problems *can* interfere with the card's detection, it usually shows much more prominently with the OS. MO! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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