From owner-freebsd-hackers Tue Jan 9 23:33:48 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id XAA17565 for hackers-outgoing; Tue, 9 Jan 1996 23:33:48 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id XAA17547 for ; Tue, 9 Jan 1996 23:33:31 -0800 (PST) Received: from msmith@localhost by genesis.atrad.adelaide.edu.au (8.6.12/8.6.9) id SAA08632; Wed, 10 Jan 1996 18:03:00 +1030 From: Michael Smith Message-Id: <199601100733.SAA08632@genesis.atrad.adelaide.edu.au> Subject: Re: Add new slice to running system, comments? To: bde@zeta.org.au (Bruce Evans) Date: Wed, 10 Jan 1996 18:02:59 +1030 (CST) Cc: bde@zeta.org.au, msmith@atrad.adelaide.edu.au, hackers@FreeBSD.ORG, phk@critter.tfs.com In-Reply-To: <199601100615.RAA29846@godzilla.zeta.org.au> from "Bruce Evans" at Jan 10, 96 05:15:46 pm MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.ORG Precedence: bulk Bruce Evans stands accused of saying: > > >Hmm. Now I'm a little confused 8) Are you saying that the vn device maps > >the on-disk location of the file (its block map, I presume) and keeps > >this internally to avoid using the fs-specific read/write functions? If > >this is the case, then I take everything back and will concentrate solely > >on using it 8) > > The file system keeps the block map. Read the code. The vn driver could > keep an optimized form of the block map (one extent for contiguous files, > a few extents for slightly discontigous files...). Write the code. One thing at a time 8) I'm still fuzzy on the merits of having to mount the filesystem before vnconfig'ing the node to get at the extent(s). Yes, I'll go read the code before bothering you anymore, but without the background understanding of What Everything Does, you spend most of your time chasing your tail 8( > Bruce -- ]] Mike Smith, Software Engineer msmith@atrad.adelaide.edu.au [[ ]] Genesis Software genesis@atrad.adelaide.edu.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control (ph/fax) +61-8-267-3039 [[ ]] "Who does BSD?" "We do Chucky, we do." [[