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Date:      Tue, 21 Apr 1998 16:37:08 -0500
From:      Dan Nelson <dnelson@emsphone.com>
To:        Doug White <dwhite@resnet.uoregon.edu>, Vallo Kallaste <vallo@matti.ee>
Cc:        freebsd-questions@FreeBSD.ORG
Subject:   Re: ncrcontrol and dmesg differences
Message-ID:  <19980421163708.A5161@emsphone.com>
In-Reply-To: <Pine.BSF.3.96.980421124722.4074X-100000@gdi.uoregon.edu>; from "Doug White" on Tue Apr 21 12:48:08 GMT 1998
References:  <Pine.GSO.3.96.980421201832.9864A-100000@solaris> <Pine.BSF.3.96.980421124722.4074X-100000@gdi.uoregon.edu>

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In the last episode (Apr 21), Doug White said:
> On Tue, 21 Apr 1998, Vallo Kallaste wrote:
> 
> > T:L  Vendor   Device           Rev  Speed   Max Wide Tags
> > 0:0  TOSHIBA  CD-ROM XM-6201TA 1030  10.0  20.0   8    -
> > 5:0  QUANTUM  VIKING 4.5 WSE   880R  20.0  20.0  16    8
> > 6:0  QUANTUM  VIKING 4.5 WSE   880R  20.0  20.0  16    8
> > 
> > but dmesg are different:
> > 
> > cd0 at scbus0 target 0 lun 0
> > cd0: 10.0 MB/s (100 ns, offset 16)
> > sd0 at scbus0 target 5 lun 0
> > sd0: WIDE SCSI (16 bit)
> > sd0: 40.0 MB/s (50 ns, offset 16)
> > 
> > Why dmesg shows me 40 MB/s and ncrcontrol 20 MB/s ? SCSI BIOS boot message
> > shows me 40 MB/s for hard drives, too. Are there something incorrect ? Of
> > course I need the full capabilities of my new drives and adapter :)

dmesg's output shows max throughput; 40.0MB/s.  Note that the cycle
timing is listed at 50 ns, which would mean a bus frequency of 20Mhz.

NCRcontrol's "max" column is the bus frequency; 20Mhz.  Multiply that
by 16 bits per operation, and you get 40MB/sec.

At least that's what it looks like from here.

	-Dan Nelson
	dnelson@emsphone.com

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