From owner-freebsd-current Thu Dec 30 22:59: 6 1999 Delivered-To: freebsd-current@freebsd.org Received: from picnic.mat.net (picnic.mat.net [206.246.122.133]) by hub.freebsd.org (Postfix) with ESMTP id 6550F14DEB; Thu, 30 Dec 1999 22:59:01 -0800 (PST) (envelope-from chuckr@picnic.mat.net) Received: from localhost (chuckr@localhost [127.0.0.1]) by picnic.mat.net (8.9.3/8.9.3) with ESMTP id BAA02112; Fri, 31 Dec 1999 01:59:04 -0500 (EST) (envelope-from chuckr@picnic.mat.net) Date: Fri, 31 Dec 1999 01:59:04 -0500 (EST) From: Chuck Robey To: Brian Fundakowski Feldman Cc: FreeBSD-current@FreeBSD.org Subject: Re: multiple cd devices In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Fri, 31 Dec 1999, Brian Fundakowski Feldman wrote: > The way certain devices, like cd with its monotonically increasing counter > where devices are probed in order and assigned device based on precedence > and not hardwiring/controller connection, work is consistent between > the kernel and MAKEDEV. If you have 2 cd devices, you have cd0 and cd1, > so MAKEDEV accepts "cd2" for "two cd devices". All CD devices work > that way. Disks don't, because there is potential for hard-wiring > there, and will often be gaps. Why are "certain" devices wildly different than all other ones? I've never encountered that kind of syntax before, and I can't see that it's documented anywhere at all. Certainly, MAKEDEV itself (in it's comments) treats cd* just like all the others, specifying that the number following is a unit number, and *not* a quantity. I don't know when this happened, but it's surely not obvious. Not one word in the handbook, either. In fact, according to cd(4), you *can* specify the unit number: ... Prior to FreeBSD 2.1, the first device found will be attached as cd0 the next, cd1, etc. Beginning in FreeBSD 2.1 it is possible to specify what cd unit a device should come on line as; refer to scsi(4) for details on kernel configura- tion. That makes this odd setup even odder. Can't understand why this was done. > > ---------------------------------------------------------------------------- Chuck Robey | Interests include C & Java programming, New Year's Resolution: I | electronics, communications, and will not sphroxify gullible| signal processing. people into looking up | I run picnic.mat.net: FreeBSD-current(i386) and fictitious words in the | jaunt.mat.net : FreeBSD-current(Alpha)| dictionary. | ---------------------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message