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NEWFS_MSDOS(8)		  BSD System Manager's Manual		NEWFS_MSDOS(8)

     newfs_msdos -- construct a	new MS-DOS (FAT) file system

     newfs_msdos [-N] [-B boot]	[-F FAT-type] [-I volid] [-L label] [-O	OEM]
		 [-S sector-size] [-a FAT-size]	[-b block-size]
		 [-c cluster-size] [-e dirents]	[-f format] [-h	heads]
		 [-i info] [-k backup] [-m media] [-n FATs] [-o	hidden]
		 [-r reserved] [-s total] [-u track-size] special [disktype]

     The newfs_msdos utility creates a FAT12, FAT16, or	FAT32 file system on
     device special, using disktab(5) entry disktype to	determine geometry, if

     The options are as	follow:

     -N	     Don't create a file system: just print out	parameters.

     -B	boot
	     Get bootstrap from	file.

     -F	FAT-type
	     FAT type (one of 12, 16, or 32).

     -I	volid
	     Volume ID.

     -L	label
	     Volume label (up to 11 characters).  The label should consist of
	     only those	characters permitted in	regular	DOS (8+3) filenames.

     -O	OEM  OEM string	(up to 8 characters).  The default is "BSD  4.4".

     -S	sector-size
	     Number of bytes per sector.  Acceptable values are	powers of 2 in
	     the range 128 through 32768.

     -a	FAT-size
	     Number of sectors per FAT.

     -b	block-size
	     File system block size (bytes per cluster).  This should resolve
	     to	an acceptable number of	sectors	per cluster (see below).

     -c	cluster-size
	     Sectors per cluster.  Acceptable values are powers	of 2 in	the
	     range 1 through 128.

     -e	dirents
	     Number of root directory entries (FAT12 and FAT16 only).

     -f	format
	     Specify a standard	(floppy	disk) format.  The standard formats
	     are (capacities in	kilobytes): 160, 180, 320, 360,	640, 720,
	     1200, 1232, 1440, 2880.

     -h	heads
	     Number of drive heads.

     -i	info
	     Location of the file system info sector (FAT32 only).  A value of
	     0xffff signifies no info sector.

     -k	backup
	     Location of the backup boot sector	(FAT32 only).  A value of
	     0xffff signifies no backup	sector.

     -m	media
	     Media descriptor (acceptable range	0xf0 to	0xff).

     -n	FATs
	     Number of FATs.  Acceptable values	are 1 to 16 inclusive.	The
	     default is	2.

     -o	hidden
	     Number of hidden sectors.

     -r	reserved
	     Number of reserved	sectors.

     -s	total
	     File system size.

     -u	track-size
	     Number of sectors per track.

     FAT file system parameters	occupy a "Boot Sector BPB (BIOS	Parameter
     Block)" in	the first of the "reserved" sectors which precede the actual
     file system.  For reference purposes, this	structure is presented below.

     struct bsbpb {
	 u_int16_t   bps;	     /*	[-S] bytes per sector */
	 u_int8_t    spc;	     /*	[-c] sectors per cluster */
	 u_int16_t   res;	     /*	[-r] reserved sectors */
	 u_int8_t    nft;	     /*	[-n] number of FATs */
	 u_int16_t   rde;	     /*	[-e] root directory entries */
	 u_int16_t   sec;	     /*	[-s] total sectors */
	 u_int8_t    mid;	     /*	[-m] media descriptor */
	 u_int16_t   spf;	     /*	[-a] sectors per FAT */
	 u_int16_t   spt;	     /*	[-u] sectors per track */
	 u_int16_t   hds;	     /*	[-h] drive heads */
	 u_int32_t   hid;	     /*	[-o] hidden sectors */
	 u_int32_t   bsec;	     /*	[-s] big total sectors */
     /*	FAT32 extensions */
     struct bsxbpb {
	 u_int32_t   bspf;	     /*	[-a] big sectors per FAT */
	 u_int16_t   xflg;	     /*	control	flags */
	 u_int16_t   vers;	     /*	file system version */
	 u_int32_t   rdcl;	     /*	root directory start cluster */
	 u_int16_t   infs;	     /*	[-i] file system info sector */
	 u_int16_t   bkbs;	     /*	[-k] backup boot sector	*/

	   newfs_msdos /dev/ad0s1

     Create a file system, using default parameters, on	/dev/ad0s1.

	   newfs_msdos -f 1440 -L foo fd0

     Create a standard 1.44M file system, with volume label foo, on /dev/fd0.

     disktab(5), disklabel(8), fdisk(8), newfs(8)

     Exit status is 0 on success and 1 on error.

     The newfs_msdos utility first appeared in FreeBSD 3.0.

     Robert Nordier <>.

BSD				 July 6, 1998				   BSD


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