From owner-freebsd-questions@FreeBSD.ORG  Sun Jul 22 21:00:27 2012
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id 17BD510656FF
	for <freebsd-questions@freebsd.org>;
	Sun, 22 Jul 2012 21:00:09 +0000 (UTC)
	(envelope-from bonomi@mail.r-bonomi.com)
Received: from mail.r-bonomi.com (mx-out.r-bonomi.com [204.87.227.120])
	by mx1.freebsd.org (Postfix) with ESMTP id 5D6278FC16
	for <freebsd-questions@freebsd.org>;
	Sun, 22 Jul 2012 21:00:09 +0000 (UTC)
Received: (from bonomi@localhost)
	by mail.r-bonomi.com (8.14.4/rdb1) id q6ML1fqO026079
	for freebsd-questions@freebsd.org; Sun, 22 Jul 2012 16:01:41 -0500 (CDT)
Date: Sun, 22 Jul 2012 16:01:41 -0500 (CDT)
From: Robert Bonomi <bonomi@mail.r-bonomi.com>
Message-Id: <201207222101.q6ML1fqO026079@mail.r-bonomi.com>
To: freebsd-questions@freebsd.org
In-Reply-To: <op.whuxsezgg7njmm@michael-think>
Subject: Re: fsck on FAT32 filesystem?
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/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: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
	<mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sun, 22 Jul 2012 21:00:27 -0000


> From: "Michael Ross" <gmx@ross.cx>
> Date: Sun, 22 Jul 2012 19:06:04 +0200
>
> On Sun, 22 Jul 2012 17:08:56 +0200, Bruce Cran <bruce@cran.org.uk> wrote:
>
> Microsoft's format.exe can zero a volume, at least in the newer (>2008)  
> versions:
>
> /p:<passes> : Zeros every sector on the volume for the number of passes  
> specified.

Early versions of format (until the addition of the '/Q' switch) always over-
wrote the entire disk.  this was how it found the initial 'bad sectors' to
be so marked in the FAT.  As disk capacities increased, the bad block check
took increasingly longer amounts of time.  Hence, along with bad-block
handling (mapping and substitution) moving into the drive electronics,
the introduction of the '/Q' option -- whereby format just overwrote the
fat and root diretory, putting all the data blocks on the free list.

I haven't had occasion to dissect a copy of format in years, I don't know
if it still defaults to one write attemptto every sector on the disk.