1) Install now creates a DOS partition for the first (and only the

first) Primary (un-Extended) DOS partition, providing /dev/xx0h
is available.  It is mounted on /dos by default.  The /etc/fstab
entry omits the dump and fsck fields, i.e.:
/dev/xx0h	/dos	pcfs rw

The Secondary DOS partition is not used (System ID 0xF2), because I don't
know what that is.

2) Fixed default sizes so that if someone attempts to install BSD on a 24 Mb
partition by accepting defaults, they don't end up with a 1 Mb /usr
partition (up to USRMIN Mb's).  In this case, all space is split between
swap and root.

TODO:
1) Extend load_fd() to support loading distribution files directly from
the DOS partition of the hard disk.

2) Provide translated parameters to the install program (maybe
add an option to fdisk).  Currently, the true geometry is used as
default, which is inappropriate for coexistence with DOS.

3) Support installing on multiple or secondary disks.

etc/etc.i386/inst1.install

@@ -11,6 +11,7 @@ OPSYSTEM=FreeBSD
 OPSYSID=165
 ROOTMIN=7
 SWAPMIN=8
+USRMIN=7
 DISKMIN=`expr $ROOTMIN + $SWAPMIN + 1`
 DEFBLOCKING=2
 DEFSECT=17
@@ -18,6 +19,10 @@ DEFHEAD=12
 DEFCYLN=1024
 RUN_FDISK=""
 
+DOS1_ID=1
+DOS2_ID=4
+DOS3_ID=6
+
 set_arbitrary_defaults() {
 cyls_per_disk=$DEFCYLN
 tracks_per_cyl=$DEFHEAD
@@ -34,6 +39,7 @@ got_sysid=
 part_cnt=0
 sysid_cnt=0
 have_opsys_part=
+have_dos_part=
 unused_last_part=
 extent_max=0
 extent_max_part=
@@ -78,7 +84,12 @@ while read data; do
 			part_id=
 			continue
 		fi
-		[ "$sysid" = "$OPSYSID" ] && have_opsys_part=$part_id
+		if [ "$sysid" = "$OPSYSID" ]; then
+			have_opsys_part=$part_id
+		elif [ ! "$have_dos_part" -a \( "$sysid" = "$DOS1_ID" -o \
+		    "$sysid" = "$DOS2_ID" -o "$sysid" = "$DOS3_ID" \) ]; then
+			have_dos_part=$part_id
+		fi
 		eval sysid${part_id}=$sysid
 		eval sysname${part_id}=\"$sysname\"
 		got_sysid=1
@@ -591,7 +602,10 @@ echo "as small as $ROOTMIN Mb ($root_cyls_min cylinders)."
 if [ ! "$cyls_per_root" ]; then
 	# set default root partition to 15MB
 	cyls_per_root=`expr \( 15 \* $mb_sect \) /  $cylindersize`
-	[ $cyls_per_root -gt $root_cyls_max ] && cyls_per_root=$root_cyls_max
+	usr_cyls_max=`expr ${root_cyls_max} - ${cyls_per_root}`
+	mb_usr=`expr ${usr_cyls_max} \* $cylindersize / $mb_sect`
+	[ $cyls_per_root -gt $root_cyls_max  -o $mb_usr -lt $USRMIN ] &&
+	cyls_per_root=$root_cyls_max
 fi
 while :; do
 	echo -n "Root partition size (in cylinders)? [${cyls_per_root}] "
@@ -735,7 +749,24 @@ while [ $part_used -lt $partition ]; do
 		part_used=partition
 	fi
 done
-
+if [ "$have_dos_part" -a ! "$hname" ]; then
+	part_name=""
+	echo	"There appears to be a MS-DOS filesystem on disk."
+	while [ "$part_name" = "" ]; do
+		echo -n "On which directory should this filesystem be mounted? [dos] "
+		read resp junk
+		part_name=${resp:-dos}
+		part_name=`expr "$part_name" : '/*\(.*\)'`
+	done
+	hname=$part_name
+	eval offset=\$start${have_dos_part}
+	eval part_size=\$size${have_dos_part}
+	echo -n "	:ph#${part_size}:oh#${offset}" >>/etc/disktab
+	echo ":th=MSDOS:\\" >>/etc/disktab
+	part_used=partition
+else
+	have_dos_part=""
+fi
 echo	"	:pd#${disksize}:od#0:" >>/etc/disktab
 sync
 
@@ -850,9 +881,14 @@ if [ "$gname" != "" ]; then
 fi
 if [ "$hname" != "" ]; then
 	echo
-	echo	"Initializing $hname filesystem, and mounting..."
-	newfs ${rotdelay} /dev/r${drivename}h $name
+	if [ ! "$have_dos_part" ]; then
+		echo	"Initializing $hname filesystem, and mounting..."
+		newfs ${rotdelay} /dev/r${drivename}h $name
+	else
+		echo	"Initializing $hname filesystem..."
+	fi
 	mkdir -p /mnt/$hname
+	[ ! "$have_dos_part" ] &&
 	mount -v /dev/${drivename}h /mnt/$hname
 fi
 
@@ -880,7 +916,11 @@ if [ "$gname" != "" ]; then
 	echo "/dev/${drivename}g	/$gname	ufs	rw 1 4" >>etc/fstab
 fi
 if [ "$hname" != "" ]; then
-	echo "/dev/${drivename}h	/$hname	ufs	rw 1 5" >>etc/fstab
+	if [ ! "$have_dos_part" ]; then
+		echo "/dev/${drivename}h	/$hname	ufs	rw 1 5" >>etc/fstab
+	else
+		echo "/dev/${drivename}h	/$hname	pcfs	rw" >>etc/fstab
+	fi
 fi
 
 # cat /etc/disktab >etc/disktab.install