From owner-freebsd-hackers Sat Dec 13 18:14:43 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id SAA13035 for hackers-outgoing; Sat, 13 Dec 1997 18:14:43 -0800 (PST) (envelope-from owner-freebsd-hackers) Received: from word.smith.net.au (ppp5.portal.net.au [202.12.71.105]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id SAA13022 for ; Sat, 13 Dec 1997 18:14:28 -0800 (PST) (envelope-from mike@word.smith.net.au) Received: from word (localhost [127.0.0.1]) by word.smith.net.au (8.8.8/8.8.5) with ESMTP id MAA04740; Sun, 14 Dec 1997 12:38:57 +1030 (CST) Message-Id: <199712140208.MAA04740@word.smith.net.au> X-Mailer: exmh version 2.0zeta 7/24/97 To: Terry Lambert cc: hackers@freebsd.org Subject: Re: blocksize on devfs entries (and related) In-reply-to: Your message of "Sat, 13 Dec 1997 21:28:25 -0000." <199712132128.OAA02173@usr06.primenet.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sun, 14 Dec 1997 12:38:57 +1030 From: Mike Smith Sender: owner-freebsd-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk > > The problem is that on all new devices the layout is both hidden and > > not easily describable. Nor can we describe the layouts of media that have > > not yet been invented. Track/cyl/sector geometry descriptions can not be > > used to describe modern disks and the picture is muddied by track buffers > > and reverse block write order (for example). > > SCSI I geometries are not directly accessable. But SCSI II geometries > are. Er, in what fashion? I don't recall any mandatory pages for zone description tables, or provision for self-describing geometry pages for new geometry techniques. > I think track buffers and reverse block write order are attributes > that could be communicated (actually, the second implies the first. 8-)). There is no standard for this, however, nor for describing the control policies that are applied to them, all of which relate to the effect that they may have on a consumer. mike