From owner-freebsd-hackers Fri May 5 09:15:28 1995 Return-Path: hackers-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id JAA01855 for hackers-outgoing; Fri, 5 May 1995 09:15:28 -0700 Received: from kitten.mcs.com (Kitten.mcs.com [192.160.127.90]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id JAA01849 ; Fri, 5 May 1995 09:15:27 -0700 Received: from mailbox.mcs.com (Mailbox.mcs.com [192.160.127.87]) by kitten.mcs.com (8.6.10/8.6.9) with SMTP id LAA26798; Fri, 5 May 1995 11:14:59 -0500 Received: by mailbox.mcs.com (/\==/\ Smail3.1.28.1 #28.5) id ; Fri, 5 May 95 11:14 CDT Received: by mercury.mcs.com (/\==/\ Smail3.1.28.1 #28.5) id ; Fri, 5 May 95 11:14 CDT Message-Id: Subject: Re: SLICES and bits in the device numbers To: dufault@hda.com (Peter Dufault) Date: Fri, 5 May 1995 11:14:46 -0500 (CDT) From: "Lars Fredriksen" Cc: bde@zeta.org.au, hackers@FreeBSD.org, julian@FreeBSD.org In-Reply-To: <199505011049.GAA20745@hda.com> from "Peter Dufault" at May 1, 95 06:49:44 am X-Mailer: ELM [version 2.4 PL24] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Content-Length: 950 Sender: hackers-owner@FreeBSD.org Precedence: bulk Peter Dufault writes: > [ stuff deleted ] > Even if I remove the fixed SCSI device (BUS-ID-LUN embedded in > major number) that can no longer work for disks, I still need a > control device for the disk that bypasses all normal processing > and only permits the ioctl (for formatting disks and fixing broken > tapes). It appears that for a disk drive, the only field that > belongs to the driver is the UNIT field. > Couldn't we use the "bus" device for all lowlevel stuff like formatting, tuning, tape fixing etc? What I mean is that we open /dev/scsi0 and blast the scsi request straight in that way. It does mean some code duplication between the different drivers and the "control" program, but if we are running out of bits, it might be worth it. Lars -- ------------------------------------------------------------------- Lars Fredriksen fredriks@mcs.com (home) lars@fredriks.pr.mcs.net (home-home) fredriks@asiago.cs.wisc.edu