From owner-aic7xxx  Fri May 26 15:28:55 2000
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Date: Fri, 26 May 2000 18:28:41 -0400
From: Doug Ledford <dledford@redhat.com>
Organization: Red Hat, Inc.
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To: crawford@goingware.com
Cc: aic7xxx@FreeBSD.ORG
Subject: Re: 64-bit PCI with SCSI?
References: <959095688_PM_BeOS.crawford@goingware.com>
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"Michael D. Crawford" wrote:
> 
> Hi,
> 
> I see from the README in the latest development kernel sources (linux)
> that the aic7xxx driver supports the Adaptec 39160 card.
> 
> This is a 64-bit PCI Ultra-160 SCSI .
> 
> I'm about to build a server and want it to go real zippy and stuff.  If
> I get one of these cards and put it in a 64 bit slot, will Linux use the
> 64-bit PCI bus?  Is this something that's perhaps handled transparently
> by the PCI bridge or does it require a kernel version with 64 bit PCI
> enabled?
> 
> Or perhaps will the 64 bit card work at the same speed as a 32 bit card
> even though it is in a 64 bit slot?
> 
> They have cheaper Ultra-160 cards that go into 32 bit slots.
> 
> BTW - I'm new to the list and sorry to be bugging you with such
> questions.  I have a little knowledge of SCSI programming (mostly
> writing scanner drivers) and hope I can contribute something more
> substantive later.
> 
> Regards,
> 
> Mike Crawford
> crawford@goingware.com
> 
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The driver uses the 64 bit transfer path (it's not entirely transparent to the
driver, in that the driver can turn off the 64 bit transfers, but why would
it?)

-- 

 Doug Ledford <dledford@redhat.com>  http://people.redhat.com/dledford
      Please check my web site for aic7xxx updates/answers before
                      e-mailing me about problems


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