Date: Tue, 12 Oct 1999 21:02:12 -0700 From: Ben Speirs <igiveup@ix.netcom.com> To: freebsd-scsi@FreeBSD.ORG Subject: Reading on Wide and Narrow channels = wide channel slows down? Message-ID: <38040444.1CE0B1DC@ix.netcom.com>
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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
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