From owner-freebsd-scsi Tue Oct 12 21: 3:17 1999 Delivered-To: freebsd-scsi@freebsd.org Received: from dfw-ix13.ix.netcom.com (dfw-ix13.ix.netcom.com [206.214.98.13]) by hub.freebsd.org (Postfix) with ESMTP id B12F314C18 for ; Tue, 12 Oct 1999 21:03:15 -0700 (PDT) (envelope-from igiveup@ix.netcom.com) Received: (from smap@localhost) by dfw-ix13.ix.netcom.com (8.8.4/8.8.4) id XAA05908 for ; Tue, 12 Oct 1999 23:03:07 -0500 (CDT) Received: from stl-wa42-08.ix.netcom.com(207.220.45.136) by dfw-ix13.ix.netcom.com via smap (V1.3) id rma005587; Tue Oct 12 23:02:20 1999 Message-ID: <38040444.1CE0B1DC@ix.netcom.com> Date: Tue, 12 Oct 1999 21:02:12 -0700 From: Ben Speirs X-Mailer: Mozilla 4.7 [en] (X11; U; FreeBSD 3.3-STABLE i386) X-Accept-Language: en MIME-Version: 1.0 To: freebsd-scsi@FreeBSD.ORG Subject: Reading on Wide and Narrow channels = wide channel slows down? Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-scsi@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org I have been debugging some hardware problems after I got a "unexpected busfree" message. I think I have narrowed it down to my 24X Toshiba CD-ROM. During my debug I noticed that when I do a dd if=/dev/rda0 of=/dev/null bs=40k systat shows a 9MB/s throughput from my 4GB Fujitsu drive (da0). If I add a dd if=/dev/rcd0c of=/dev/null bs=8k to read from my 3X NEC CD-ROM, systat reports that the throughput drops to below 1 MB/s on da0. The CD-ROM has a higher throughput than the fast hard drive. What gives? Is this normal? Thanks for sharing your wisdom. Oh, FYI, I'm using an adaptec 2940UW PCI controller. -- -Ben Speirs To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message