From owner-cvs-all Fri Oct 25 10:45:15 2002 Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 182B537B404; Fri, 25 Oct 2002 10:45:14 -0700 (PDT) Received: from tonnant.cnchost.com (tonnant.concentric.net [207.155.248.72]) by mx1.FreeBSD.org (Postfix) with ESMTP id 46D8E43E3B; Fri, 25 Oct 2002 10:45:13 -0700 (PDT) (envelope-from bakul@bitblocks.com) Received: from bitblocks.com (adsl-209-204-185-216.sonic.net [209.204.185.216]) by tonnant.cnchost.com id NAA24610; Fri, 25 Oct 2002 13:44:16 -0400 (EDT) [ConcentricHost SMTP Relay 1.14] Message-ID: <200210251744.NAA24610@tonnant.cnchost.com> To: Mark Valentine Cc: Poul-Henning Kamp , Takahashi Yoshihiro , bde@zeta.org.au, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/lib/libdisk Makefile chunk.c write_alpha_disk.c write_i386_disk.c write_pc98_disk.c In-reply-to: Your message of "Fri, 25 Oct 2002 13:16:19 BST." <200210251216.g9PCGJtO068434@dotar.thuvia.org> Date: Fri, 25 Oct 2002 10:44:16 -0700 From: Bakul Shah Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG > > >/dev/motherboard/pcibus/0/pcib/0/pci/0/7/0/ahc/0/0/0/0/da/0/4/a/kernel, > > >anyone? :-) There is always one wiseguy....:-) > Seriously, though, there are merits to something like the Solaris /devices > and /dev distinction between physical and logical device names (though they > still kept the SysV brain damaged /dev names). IMHO devfs could've automagically built /devices, not /dev. What with USB and all, the actual controller/device tree can be pretty dynamic and best discovered automatically. [Aside: is anyone looking at iSCSI, serial ATA etc.?] /dev is still needed and can be built somewhat more intelligently. If each disk had its own unique id (like what each CD has), moving disks around would change /devices but /dev can still look the same. Something like /dev/da0a -> -> /devices/ahc0/bus0/target0/lun0/... Something in the system will have to keep track of the /dev/ to unique id mapping. In general any device that can be uniquely identified can be handled this way. This scheme is not perfect either -- how do you ensure unique ids? What do you do when an exact copy disk is attached? etc. My point is this: if you are going to fix the system, don't make many mickey-mouse changes that may break compatibility and encourage endless debates. Instead think things through, learn from what previous systems have done, look at usage patterns, changes in them, look at future directions and then come up with a coherent design (may be even a total revamp!) and *provide backward compatibility (if at all possible) and tools for upgrading*. Not exactly a JKH task. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message