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Date:      Thu, 25 Feb 1999 12:03:25 -0800
From:      Darryl Okahata <darrylo@sr.hp.com>
To:        Andrew Gallatin <gallatin@cs.duke.edu>
Cc:        scsi@FreeBSD.ORG
Subject:   Re: dual-channel U2W scsi performance 
Message-ID:  <199902252003.MAA06761@mina.sr.hp.com>
In-Reply-To: Your message of "Tue, 23 Feb 1999 16:27:52 EST." <14035.5458.71518.652907@grasshopper.cs.duke.edu> 

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Andrew Gallatin <gallatin@cs.duke.ed> wrote:

> Justin T. Gibbs writes:
>  > 
>  > There must be something wrong with your cables.  I've had several instance
> s
>  > where a loose connector pin caused intermittent parity-errors.  If both
>  > the driver and the end device are reporting errors, they can't be wrong.
>  > I've tested SE operation on the aic7896, so I know that it can work
>  > with the current driver.
> 
> Before I turned off parity in scsi-select, I tried all possible
> combinations of cabling (my setup is motherboard connecter -> internal
> cable -> external connector-> external cable -> box w/2 4G cheetahs ->
> active terminator), I switched out both cables, the external
> connector, the terminator & the box w/2 cheetahs.. No combination
> worked on the second channel.  All combinations worked on the first
> channel.  (by worked, I mean probed w/o parity errors)

     How long is the total cable length, starting at the motherboard?
At 20MHz, the max cable length is something like 1.5 meters, or a bit
less than 5 feet.  Also, you are using high-quality external cables,
right?

--
	Darryl Okahata
	darrylo@sr.hp.com

DISCLAIMER: this message is the author's personal opinion and does not
constitute the support, opinion, or policy of Hewlett-Packard, or of the
little green men that have been following him all day.



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