Date: Wed, 28 Aug 1996 21:33:05 -0700 (PDT) From: "Rodney W. Grimes" <rgrimes@GndRsh.aac.dev.com> To: richard@pegasus.com (Richard Foulk) Cc: freebsd-hardware@FreeBSD.org Subject: Re: DAT or removable device? Message-ID: <199608290433.VAA00814@GndRsh.aac.dev.com> In-Reply-To: <199608290314.RAA08700@pegasus.com> from Richard Foulk at "Aug 28, 96 05:14:14 pm"
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> } * Supposedly, the NCR/Symbios-based cards don't perform well under heavy > } loads, such as when you have three or more disks being accessed > } *simultaneously*. This isn't an issue for most people. > > This appears to be hearsay. No numbers have been presented. This is not hearsay. I can't give you numbers that mean a whole lot, they are from running a PCI bus analyzer. The busier a NCR 53Cxxx gets the more PCI bandwidth, and host memory bandwidth gets eaten up. And I am not talking about the data transfer bandwidth (though that is the majority of the PCI traffic), but the microcode fetch bandwidth. I do not recommend running lots of drives or lots of 53C8xx's in a machine for that very reason, UNLESS lower cost is an objective and performance can suffer by reducing the cost. -- Rod Grimes rgrimes@gndrsh.aac.dev.com Accurate Automation Company Reliable computers for FreeBSD
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