Date: Mon, 1 Nov 1999 21:44:57 -0700 (MST) From: "Kenneth D. Merry" <ken@kdm.org> To: jdetar@EIComm.net (Jason Detar) Cc: freebsd-stable@FreeBSD.ORG Subject: Re: scsi negotiation problem... Message-ID: <199911020444.VAA41906@panzer.kdm.org> In-Reply-To: <GLEHIBJPEIDECCMMOMOJCEGNCAAA.jdetar@EIComm.net> from Jason Detar at "Nov 1, 1999 07:54:45 pm"
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[ It is generally best to send SCSI questions to the freebsd-scsi list ] Jason Detar wrote... > For some odd reason on one of my boxes the SCSI devices are coming up as > scsi-3 40MB/sec instead of 80MB/sec Ultra 2/LVD. > > box2 it comes up ok... > da0 at ahc0 bus 0 target 0 lun 0 > da0: <IBM DNES-309170W SA30> Fixed Direct Access SCSI-3 device > da0: 80.000MB/s transfers (40.000MHz, offset 31, 16bit), Tagged Queueing > Enabled > da0: 8748MB (17916240 512 byte sectors: 255H 63S/T 1115C) > > but box3 has 2 hd's and comes up like this... > da1 at ahc0 bus 0 target 1 lun 0 > da1: <IBM DNES-309170W SA30> Fixed Direct Access SCSI-3 device > da1: 40.000MB/s transfers (20.000MHz, offset 31, 16bit), Tagged Queueing > Enabled > da1: 8748MB (17916240 512 byte sectors: 255H 63S/T 1115C) > da0 at ahc0 bus 0 target 0 lun 0 > da0: <IBM DNES-309170W SA30> Fixed Direct Access SCSI-3 device > da0: 40.000MB/s transfers (20.000MHz, offset 31, 16bit), Tagged Queueing > Enabled > da0: 8748MB (17916240 512 byte sectors: 255H 63S/T 1115C) > > The HD's are identical, so is the SCSI card and setup for it all.. would the > fact of it being 2 drive's causing this problem or what could it be? There are a number of factors that can cause this problem: - many (most?) LVD drives have a jumper that forces single-ended negotiation. - controllers like the Adaptec 2940U2W, and many motherboards that have onboard 7890's have a wide LVD connector and a wide SE connector. If your drives are plugged into the wrong connector, your drives will negotiate at the lower single-ended rate. - the BIOS settings on the card could be wrong. Make sure that the card BIOS is setup to negotiate at LVD speeds. - you might have other single-ended devices on an LVD SCSI bus segment. If there are any single-ended devices on an LVD-capable bus, the entire bus will be single ended. Also, I'm not sure what would happen if your cable were incorrectly terminated. Make sure you've got a "twisty" LVD cable with a terminator block on the end. (LVD disks don't have on-board terminators.) Ken -- Kenneth Merry ken@kdm.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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