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Subject: Re: Intelligent Debugging Tools... 
In-reply-to: Your message of "Wed, 24 Apr 1996 01:32:35 PDT."
             <199604240832.BAA04088@GndRsh.aac.dev.com> 
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Date: Wed, 24 Apr 1996 01:45:47 -0700
From: "Amancio Hasty Jr." <hasty@rah.star-gate.com>
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I hope that all this useful information about scsi goes into the FreeBSD
Handbook 8)

	Cheers,
	Amancio


>>> "Rodney W. Grimes" said:
 > > >5. make sure that one of the drives is sending the termination power
 > > 
 > >    For external termination, this is normally done by the controller, not 
     any
 > > of the drives.
 > 
 > True.
 > 
 > > Most people terminate the last drive with the drive's termination
 > 
 > I would disagree with that, most people use an external terminator on
 > an external chain.  Turning terminators on inside of external scsi
 > enclosures is a no no in my book, it often leads to multiple termination
 > when someone not so informed adds something to a chain.  Or middle
 > termination with a floating end when a chain gets swapped around.
 > 
 > > and configure that drive to supply it's on termination power
 >                                           ^^ own
 > For external scsi chains of any length > 3 feet I would _strongly_ encourage
 > the use of drive supplied termination power (preferably from the last
 > drive on the chain) to the scsi bus.  
 > 
 > > (which is usually the factory default).
 > 
 > With the advent of the SCSI PnP spec this and other defaults are rapidly
 > changing, the SCSI PnP spec requires that drives ship with no termination
 > enabled, the use of on drive termination is verboten, you are suppose to
 > use cable end terminators both internally and externally.  I don't seem
 > to recally anything about term power though :-(.
 > 
 > -- 
 > Rod Grimes                                      rgrimes@gndrsh.aac.dev.com
 > Accurate Automation Company                 Reliable computers for FreeBSD