From owner-freebsd-questions@freebsd.org  Mon Sep 26 03:41:51 2016
Return-Path: <owner-freebsd-questions@freebsd.org>
Delivered-To: freebsd-questions@mailman.ysv.freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by mailman.ysv.freebsd.org (Postfix) with ESMTP id 86821BEAEE9
 for <freebsd-questions@mailman.ysv.freebsd.org>;
 Mon, 26 Sep 2016 03:41:51 +0000 (UTC)
 (envelope-from dpchrist@holgerdanske.com)
Received: from holgerdanske.com (holgerdanske.com [184.105.128.27])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client CN "*.he.net", Issuer "GeoTrust SSL CA - G4" (not verified))
 by mx1.freebsd.org (Postfix) with ESMTPS id 795C2866
 for <freebsd-questions@freebsd.org>; Mon, 26 Sep 2016 03:41:51 +0000 (UTC)
 (envelope-from dpchrist@holgerdanske.com)
Received: from ::ffff:99.100.19.101 ([99.100.19.101]) by holgerdanske.com
 for <freebsd-questions@freebsd.org>; Sun, 25 Sep 2016 20:36:15 -0700
To: freebsd-questions@freebsd.org
From: David Christensen <dpchrist@holgerdanske.com>
Subject: FreeBSD-10.3-RELEASE-i386-memstick.img installer changes contents of
 USB flash drive?
X-Enigmail-Draft-Status: N1110
Message-ID: <56532342-f2d4-377d-605b-2e1b5bfb2160@holgerdanske.com>
Date: Sun, 25 Sep 2016 20:36:15 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Icedove/45.2.0
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.23
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions/>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Mon, 26 Sep 2016 03:41:51 -0000

freebsd-questions:

Using Debian GNU/Linux 7.11, I downloaded
FreeBSD-10.3-RELEASE-i386-memstick.img and burned it to a USB flash drive:

        # time dd if=FreeBSD-10.3-RELEASE-i386-memstick.img of=/dev/sdc
bs=1M conv=sync; sync
        659+1 records in
        660+0 records out
        692060160 bytes (692 MB) copied, 141.567 s, 4.9 MB/s

        real    2m21.571s
        user    0m0.004s
        sys     0m1.696s


If I compute the checksum immediately after burning, it matches the
published checksum:

        # time dd if=/dev/sdc count=1350917 | sha256sum -b
        ab104a30627754bb8d39eeff3c5c5a4a15537d32c749e2b9841b34cb08e17eb0 *-
        1350917+0 records in
        1350917+0 records out
        691669504 bytes (692 MB) copied, 43.252 s, 16.0 MB/s

        real    0m43.257s
        user    0m7.236s
        sys     0m3.496s

        # grep
ab104a30627754bb8d39eeff3c5c5a4a15537d32c749e2b9841b34cb08e17eb0
CHECKSUM.SHA256-FreeBSD-10.3-RELEASE-i386
        SHA256 (FreeBSD-10.3-RELEASE-i386-memstick.img) =
ab104a30627754bb8d39eeff3c5c5a4a15537d32c749e2b9841b34cb08e17eb0


But after using the USB flash drive to install FreeBSD, the checksum has
changed:

        # dd if=/dev/sdc count=1350917 | sha256sum -b
        1350917+0 records in
        1350917+0 records out
        bd159b85486322febe992226bbec9c86d96d70dd1e5a8b7c6f0bb9d29eb50df3 *-
        691669504 bytes (692 MB) copied, 42.989 s, 16.1 MB/s


Therefore, the FreeBSD-10.3-RELEASE-i386-memstick.img installer has
changed the contents of the USB flash drive.


Why?


David