When calculating the number of disks, take into account that every

floppy needs an 8KB tar volume header, not just the first.
Fixes size calculation bug reported by Frank van der Linden.

distrib/common/buildfloppies.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 #
-# $NetBSD: buildfloppies.sh,v 1.6 2003/03/07 09:33:53 lukem Exp $
+# $NetBSD: buildfloppies.sh,v 1.7 2003/11/09 23:44:48 lukem Exp $
 #
 # Copyright (c) 2002-2003 The NetBSD Foundation, Inc.
 # All rights reserved.
@@ -63,6 +63,11 @@ plural()
 	[ $1 -ne 1 ] && echo "s"
 }
 
+roundup()
+{
+	echo $(( ( $1 + $2 - 1 ) / ( $2 ) ))
+}
+
 
 #	parse and check arguments
 #
@@ -96,7 +101,6 @@ floppy=floppy.$$.tar
 trap "rm -f ${floppy}" 0 1 2 3			# EXIT HUP INT QUIT
 rm -f ${floppybase}?${suffix}
 
-
 #	create tar file
 #
 dd if=/dev/zero of=${floppy} bs=8k count=1 2>/dev/null
@@ -111,14 +115,17 @@ fi
 #	check size against available number of disks
 #
 bytes=$( ls -l "${floppy}" | awk '{print $5}' )
-blocks=$(( ${bytes} / 512 ))
-numdisks=$(( ( ${blocks} + ${floppysize} - 1 ) / ${floppysize} ))
+blocks=$(roundup ${bytes} 512)
+	# when calculating numdisks, take into account:
+	#	a) the image already has an 8K tar header prepended
+	#	b) each floppy needs an 8K tar volume header
+numdisks=$(roundup ${blocks}-16 ${floppysize}-16)
 if [ -z "${maxdisks}" ]; then
 	maxdisks=${numdisks}
 fi
 
 if [ ${numdisks} -gt ${maxdisks} ]; then
-	excess=$(( ( ${blocks} - ${floppysize} * ${maxdisks} ) * 512 ))
+	excess=$(( ( ${blocks} - (${floppysize} - 16) * ${maxdisks} ) * 512 ))
 	echo 1>&2 \
 	    "$prog: Image is ${excess} bytes ($(( ${excess} / 1024 )) KB)"\
 	    "too big to fit on ${maxdisks} disk"$(plural ${maxdisks})
@@ -165,13 +172,6 @@ while [ ${curdisk} -le ${numdisks} ]; do
 	curdisk=$(( ${curdisk} + 1 ))
 done
 
-#
-# XXX:	the old bootfloppy generation code used to zero the last 0.5k of the
-#	end of the image in single disk configs; that possibly trashed real
-#	data???
-#	is that functionality still required?
-#
-
 #	pad last disk if necessary
 #
 if [ -n "${pad}" ]; then