NAME    [Toc]    [Back]

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

SYNOPSIS    [Toc]    [Back]

     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]

DESCRIPTION    [Toc]    [Back]

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

     The options are as follows:

     -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 eight
standard formats
 are (capacities in kilobytes): 160,  180,  320,
360, 720,
             1200, 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.

NOTES    [Toc]    [Back]

     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 */
     };

EXAMPLES    [Toc]    [Back]

     Create  a  file  system,  using   default   parameters,   on
/dev/rwd0i.
           newfs_msdos /dev/rwd0i

     Create  a  standard  1.44M  file  system,  with volume label
"foo", on
     /dev/rfd0c.
           newfs_msdos -f 1440 -L foo fd0c

DIAGNOSTICS    [Toc]    [Back]

     Exit status is 0 on success and 1 on error.

SEE ALSO    [Toc]    [Back]

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

HISTORY    [Toc]    [Back]

     The newfs_msdos command first appeared in OpenBSD 2.1.

AUTHORS    [Toc]    [Back]

     Robert Nordier <[email protected]>.

OpenBSD      3.6                           July      6,      1998