Date: Sat, 1 Aug 1998 05:43:43 -0400 (EDT) From: Peter Dufault <dufault@hda.com> To: gibbs@plutotech.com (Justin T. Gibbs) Cc: ckempf@enigami.com, ken@plutotech.com, freebsd-scsi@FreeBSD.ORG Subject: Re: dev links won't open. Why? Message-ID: <199808010943.FAA13542@hda.hda.com> In-Reply-To: <199807312221.QAA07881@pluto.plutotech.com> from "Justin T. Gibbs" at "Jul 31, 98 04:16:13 pm"
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> It is not a design flaw in the least. The old SCSI layer forced every > driver to know about some common ioctls so that they were all essentially > "pass-thru". This makes it really difficult to get locking semantics > correct for safe device access. That's the whole reason why the pass-thru > interface is in a separate device instance and that a mapping pass is > required. Minor nit not addressing locking issues - the old SCSI layer intercepted the control device at the top and passed unknown SCSI commands to common code at the bottom. Since one of my goals was to pull duplicated code to a single place I want to point that out. However, duplicated code kept sneaking back in to all the drivers. Hopefully the CAM authors with a team working on the system (now and in the future) will keep future releases to their design. Peter -- Peter Dufault (dufault@hda.com) Realtime development, Machine control, HD Associates, Inc. Safety critical systems, Agency approval To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-scsi" in the body of the message
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