Date: Mon, 20 Apr 1998 18:24:02 -0700 (PDT) From: dan@math.berkeley.edu (Dan Strick) To: dkelly@hiwaay.net Cc: dan@math.berkeley.edu, hardware@FreeBSD.ORG, shocking@prth.pgs.com Subject: Re: Narrow SCSI controllers, and using WIDE drives with them Message-ID: <199804210124.SAA07969@math.berkeley.edu>
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> > It ought to work by default. If not, you may be able to tell the > > host adapter via its BIOS interface to only do narrow transfers > > with specific SCSI devices. > > That's sorta hard to do with a narrow controller as all I've seen are > not capable of wide negotiations therefore its not an option. In that case (narrow host adapter), narrow transfers are automatic. You shouldn't have to set any options because the narrow host adapter has not got the concept of wide and should not generate the SCSI message that negotiates wide SCSI transfers. If the drive sends the message, the host adapter should reject it as an unknown message. Either way, the transfers should default to narrow. > My 2940 (narrow with the 7860 chipset and BIOS 1.21) didn't like a wide > drive that was attached. I dunno. It looks like somebody is not adhering to the standard. If you care enough to figure out who to blame, buy a SCSI bus analyzer, a copy of the SCSI-2 standard, and set aside a lot of time for playing with your new toys. It used to be that a lot of the SCSI draft standards could be found at <http://www.symbios.com/x3t10/>. You can get copies of the final "published" standards only from ANSI (or in some cases from Global Engineering Documents). The SCSI-2 standard consists of one main document and several special purpose afterthoughts. The SCSI-3 standard is fragmented into a couple of dozen separate standards, most of them not yet published. I am not sure exactly which standards you will need. Wide transfers are defined in the main SCSI-2 standard, but the single 68 conductor interface is not. I know I have seen the pinout somewhere... Try the "EPI" technical report. It might tell you that I am completely wrong about this configuration working. Dan Strick dan@math.berkeley.edu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hardware" in the body of the message
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