Date: Tue, 18 Feb 1997 18:21:12 -0500 (EST) From: John Fieber <jfieber@indiana.edu> To: Michael Smith <msmith@atrad.adelaide.edu.au> Cc: hardware@freebsd.org Subject: Re: Motherboard doesn't like tape drive Message-ID: <Pine.BSF.3.95q.970218181301.291D-100000@fallout.campusview.indiana.edu> In-Reply-To: <199702182310.JAA07385@genesis.atrad.adelaide.edu.au>
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On Wed, 19 Feb 1997, Michael Smith wrote:
> > The one tunable parameter on the archive viper is the buffer
> > disconnect size. It is currently at 16K (factory default), but
> > can be adjusted between 2K and 32K. Could that be a factor here?
>
> Indeed. Is that the high-water or low-water mark for disconnect?
>From the manual:
"The buffer disconnect size sets the maximum number of bytes that
can be sent over the SCSI bus during a single data transfer
phase. During lengthy data transfers, this feature periodically
frees the bus for other operations; thus, the disocnnect size can
affect overall system performance where more than two SCSI
devices must arbitrate for bus time. Optimum disconnect size is
a function of both the number of devices and the speed at which
they independently process data burts."
On the jumper chart, there is a footnote saying that
"Disconnect size setting 16K is minimum for using the Copy command."
> Try fiddling it and see 8)
My computer hold up one end of some boards I call a bookshelf.
Hardware fiddling is always a hassle. :(
-john
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