From owner-freebsd-fs@FreeBSD.ORG Sat May 19 16:50:18 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 50C1810656D1 for ; Sat, 19 May 2012 16:50:18 +0000 (UTC) (envelope-from ef@math.uni-bonn.de) Received: from ems.math.uni-bonn.de (ems.math.uni-bonn.de [131.220.132.179]) by mx1.freebsd.org (Postfix) with ESMTP id 161338FC15 for ; Sat, 19 May 2012 16:50:18 +0000 (UTC) Received: from mz4.intra.net (pD9E80152.dip0.t-ipconnect.de [217.232.1.82]) by ems.math.uni-bonn.de (Postfix) with ESMTPSA id 209E8BC9A5 for ; Sat, 19 May 2012 18:50:17 +0200 (CEST) From: =?iso-8859-1?Q?Edgar_Fu=DF?= Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Date: Sat, 19 May 2012 18:50:16 +0200 Message-Id: To: freebsd-fs@freebsd.org Mime-Version: 1.0 (Apple Message framework v1084) X-Mailer: Apple Mail (2.1084) Subject: Book on FFS X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 May 2012 16:50:18 -0000 Is there a book (or other documentation) about FFS giving more details = than the 4.4BSD bible? I'm writing a Perl script that takes a subset of newfs's arguments, = reads a find -ls output and computes the fragmentation/bookkeeping = overhead for that particular data set. (The intent is to find out how = much the newfs parameters actually matter in terms of overhead for that = given data set.) In the course of researching what the exact overhead for the free list, = inodes and CG heads is, I learned (from discussions on NetBSD's = tech-kern list and from reading ufs/ffs/fs.h and mkfs.c) various = "interesting" things like files that need indirect blocks not being = allocated fragments, "number of blocks" and "number of data blocks" = (i.e. fs_size and fs_dsize) being in units of fragments, not blocks. I = suspect there is way more for me to learn in this field.=