[4165] in linux-scsi channel archive
Re: Ultra Wide (aic-7880) only 20Mbyte/sec?
daemon@ATHENA.MIT.EDU (Eric Hegstrom)
Thu Jun 18 12:29:45 1998
Date: Thu, 18 Jun 1998 09:18:52 -0700
From: ehegstrom@agavesys.com (Eric Hegstrom)
Reply-To: ehegstrom@agavesys.com
To: linux-scsi@vger.rutgers.edu
> > (scsi0:-1:-1:-1) Allocating initial 30 SCB structures.
> > (scsi0:0:0:0) Using wide (16 bit) transfers.
> > (scsi0:0:0:0) Synchronous at 20.0MHz, offset 8.
> > Vendor: IBM Model: DCAS-34330W Rev: S65A
> > Type: Direct-Access ANSI SCSI revision: 02
> >
> > As far as i know, drives with ultra/wide SCSI interface should do 40
> > MByte/sec. So why is this disk running at 20Mbyte/sec? The Controller
> > BIOS is set up to do 40 MByte/sec on SCSI id 0. The disk shoudl do
> > ultra SCSI according to IBM's web pages.
The way I read the data you are getting 40MB/sec. Since you are doing 16bit (2
byte) transfers at a rate of 20MHz that is 20x2 (=40) MB/sec.
--
Eric Hegstrom tele: 520-792-9776
Agave Systems fax: 520-388-9031
http://www.agavesys.com email: ehegstrom@agavesys.com
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