[5105] in linux-scsi channel archive
Re: Linux as a SCSI _Target_ device?
daemon@ATHENA.MIT.EDU (Kurt Garloff)
Thu Nov 12 11:14:22 1998
Date: Thu, 12 Nov 1998 09:31:41 +0100
From: Kurt Garloff <garloff@kg1.ping.de>
To: MOLNAR Ingo <mingo@chiara.csoma.elte.hu>, Jeff Noxon <jeff@planetfall.com>
Cc: linux-kernel@vger.rutgers.edu, linux-scsi@vger.rutgers.edu,
linux-raid@vger.rutgers.edu
Mail-Followup-To: MOLNAR Ingo <mingo@chiara.csoma.elte.hu>,
Jeff Noxon <jeff@planetfall.com>, linux-kernel@vger.rutgers.edu,
linux-scsi@vger.rutgers.edu, linux-raid@vger.rutgers.edu
In-Reply-To: <Pine.LNX.3.96.981111234018.3802B-100000@chiara.csoma.elte.hu>; from MOLNAR Ingo on Wed, Nov 11, 1998 at 11:48:22PM +0100
On Wed, Nov 11, 1998 at 11:48:22PM +0100, MOLNAR Ingo wrote:
> of CPU time, but this isnt a problem for a dedicated box) I'd worry more
> about PCI bandwith, and about those custom 'generic SCSI device' cards.
> (with such a solution, IO bandwith goes through the PCI bus twice, so we
> have a max about ~100MB/sec)
AFAIK, PCI bandwidth is 133MB/s (33MHz, 32bit), so if you have to transfer
data twice over PCI, you will hardly get more than 60MB/s. (Or maybe 68MB/s
if your overclock your PCI to 37.5MHz, what almost any device will still
accept.)
The specification allows for 67MHz PCI devices, but I don't know such SCSI
controllers, only AGP graphics cards (which have a trick to double bandwidth
again, resulting in 533 MB/s).
--
Kurt Garloff <K.Garloff@ping.de> (Dortmund, FRG)
PGP key on http://student.physik.uni-dortmund.de/homepages/garloff
Unix IS user friendly - it's just selective about who its friends are!
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