Date: Thu, 11 Jul 1996 05:25:32 -0500 From: "Daniel M. Eischen" <deischen@iworks.InterWorks.org> To: freebsd-questions@freebsd.org, mark@ucsalf.ac.uk Subject: Re: Does Adaptec 7880 Ultra support simultaneous wide and narrow transfers? Message-ID: <9607111025.AA10945@iworks.InterWorks.org>
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> I have a motherboard with a built in 7880 Ultra with a narrow and a wide connector > surface mounted. I have a Conner CFP4207S on the narrow channel with TERM/PWR enabled > and a Conner CFP4207W on the wide channel with TERM/PWR enabled. I wanted to move my > FreeBSD-2.1-stable filesystem from the narrow disk to the wide. I assumed that I could > simply copy all the data over with (narrow on sd0, wide on sd1; with 512k on board > data buffer): > > $ dd if=/dev/sd0c of=/dev/sd1c bs=512k > > However, this only yields data transfer rates in the 200K/s range. I've tried both > larger and smaller buffer sizes with no apparent increase. I'm beginning to wonder > if the 7870 chipset is performing these transfers simultaneously. I would expect > such a command to push both drives at full speed with the drive access lights on > solidly. However, the drive lights are alternating off/no for around 1 sec. periods. > Am I expecting the wrong thing here? > If I turn on WIDE negotiation for the W drive, the kernel enables 16bit transfers: When did you get your -stable system? There were some bug fixes that were incorporated into the aic7xxx driver in late June. Make sure you're running a -stable after that date. If you want to increase performance, add option "AHC_TAGENABLE" to your kernel configuration. If all your devices handle tagged queueing properly, then you can try adding "AHC_SCBPAGING_ENABLE" to your kernel configuration also. For devices on both internal narrow and wide channels, you should have termination set to Low Off / High On. Dan Eischen deischen@iworks.InterWorks.org
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