From owner-freebsd-fs@FreeBSD.ORG Tue Jul 24 16:06:29 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 7CE02106564A for ; Tue, 24 Jul 2012 16:06:29 +0000 (UTC) (envelope-from sam@athyriogames.com) Received: from madonna.sslcatacombnetworking.com (madonna.sslcatacombnetworking.com [174.133.19.130]) by mx1.freebsd.org (Postfix) with ESMTP id 544DF8FC16 for ; Tue, 24 Jul 2012 16:06:29 +0000 (UTC) Received: from c-98-206-215-156.hsd1.in.comcast.net ([98.206.215.156] helo=laptopv) by madonna.sslcatacombnetworking.com with esmtpa (Exim 4.69) (envelope-from ) id 1SthUr-0004eT-Gh for freebsd-fs@freebsd.org; Tue, 24 Jul 2012 10:58:05 -0500 From: "Sam Zehr" To: References: <01bf01cd66d4$84756b40$8d6041c0$@com> In-Reply-To: Date: Tue, 24 Jul 2012 11:06:13 -0500 Message-ID: <02b201cd69b6$413ea000$c3bbe000$@com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: Ac1n79ThjOimdovbTMyGtPbKxV0izQBxNvHA Content-Language: en-us X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - madonna.sslcatacombnetworking.com X-AntiAbuse: Original Domain - freebsd.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - athyriogames.com Subject: Make disk completely read-only? 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: Tue, 24 Jul 2012 16:06:29 -0000 Hi, this is Sam again, working on making a USB flash drive in FreeBSD 9.0 _completely_ read-only. Disk is mounted read-only - fstab has ro,noatime Following some advice from the list, I've done some binary compares to see what is going on. It looks like only a few bytes are changing every time I reboot, they seem to correspond with the superblock locations - I would guess a timestamp of mount time? I executed the dumpfs command after a few boots, and checked for differences. The only thing that is changing is from the first line Pass 1: magic 19540119 (UFS2) time Mon Jul 23 11:12:06 2012 superblock location 65536 id [ 4fe363f7 e7fd3a99 ] Pass 2: magic 19540119 (UFS2) time Mon Jul 23 11:28:35 2012 superblock location 65536 id [ 4fe363f7 e7fd3a99 ] Does anyone know of a way to stop this timestamp from occurring? Sam