Date: Tue, 13 Mar 2001 00:24:01 -0600 From: "Jeffrey J. Mountin" <jeff-ml@mountin.net> To: Jean-Marc Zucconi <jmz@FreeBSD.ORG>, freebsd-stable@FreeBSD.ORG Subject: Re: UDMA 33/UDMA 100 perfs Message-ID: <4.3.2.20010313002151.02d94c70@207.227.119.2> In-Reply-To: <200103130329.f2D3TXN73556@freefall.freebsd.org>
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At 07:29 PM 3/12/01 -0800, Jean-Marc Zucconi wrote: >Is this the normal behavior expected? > >1) >ata0-master: DMA limited to UDMA33, non-ATA66 compliant cable >ad0: 19092MB <WDC WD200EB-00BHF0> [38792/16/63] at ata0-master using UDMA33 ># dd if=/dev/ad0e of=/dev/null bs=1m count=1000 >1048576000 bytes transferred in 49.445390 secs (21206750 bytes/sec) > >2) >ad0: 19092MB <WDC WD200EB-00BHF0> [38792/16/63] at ata0-master UDMA100 ># dd if=/dev/ad0e of=/dev/null bs=1m count=1000 >1048576000 bytes transferred in 49.337278 secs (21253220 bytes/sec) > >I get the same performance in both cases. This is with a 4.3-BETA >kernel. I have only one drive on the IDE bus. Just because the speed limit goes up doesn't mean your car will go faster. To wit there are few drives that can exceed what UDMA33 can handle and only then would the higher "speed limit" help. Jeff Mountin - jeff@mountin.net Systems/Network Administrator FreeBSD - the power to serve To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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