Re: Linux as a SCSI _Target_ device?

Kurt Garloff (garloff@kg1.ping.de)
Thu, 12 Nov 1998 09:31:41 +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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