From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <1163465375.4559129f881cc@webmail.in-berlin.de>
Date: Tue, 14 Nov 2006 01:49:35 +0100
From: Michael =?iso-8859-1?b?VGVpY2hncuRiZXI=?= <mt@wmipf.in-berlin.de>
To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
Subject: Re: [9fans] using opendisk on a sd partition
References: <1163446457.4558c8b9db16b@webmail.in-berlin.de>
	<ee9e417a0611131505m5a664839vb20c37859c20167f@mail.gmail.com>
In-Reply-To: <ee9e417a0611131505m5a664839vb20c37859c20167f@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
User-Agent: Internet Messaging Program (IMP) 3.2.6
Content-Transfer-Encoding: quoted-printable
Topicbox-Message-UUID: dde910bc-ead1-11e9-9d60-3106f5b1d025

It seems that disk/format is using the c/h/s values under
a certain condition. If type is `hard' and you provide the -f
option (which I did following some examples), disk->c/h/s will
have an influence on the size of the created fat system:

	if(t->sectors =3D=3D 0 && strcmp(type, "hard") =3D=3D 0) {
		t->sectors =3D disk->s;
		t->heads =3D disk->h;
		t->tracks =3D disk->c;
	}

	...

	if(fflag){
		disk->size =3D t->bytes*t->sectors*t->heads*t->tracks;
		disk->secsize =3D t->bytes;
		disk->secs =3D disk->size / disk->secsize;
	}

I'm wondering whether `fflag' somehow is used with different
meanings in format.c. The first is explained for `-f' in the
man-page: don't low-level format a floppy, for other devices
it's a no-op. Moreover, in the context above it seems to
be used as `is-a-file' flag: The code makes sure that the
size-related members of `disk' are set to proper values, in case it
is perhaps a file that is too small to contain an image of the
selected fd type. Some lines later the file would be expanded
to meet disk->size. Perhaps the condition above should read

	if(disk->type =3D=3D Tfile){

then -f resp. fflag would really be a no-op for non-floppy
devices (and disk->c would be ignored, while h and s still
are stored into the fat parameter block).

Michael