NEWFS_MSDOS

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NAME

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

SYNOPSIS

newfs_msdos [-N ] [-B boot ] [-F FAT-type ] [-I volid ] [-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 ] [-v volume-name ] special [disktype ]  

DESCRIPTION

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 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.
-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, 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.
-v volume-name
Volume name (filesystem name), up to 11 characters. The name should consist of only those characters permitted in regular DOS (8+3) filenames.

 

NOTES

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

        newfs_msdos /dev/disk0s1

Create a file system, using default parameters, on /dev/disk0s1.

        newfs_msdos -f 1440 -v foo fd0

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

SEE ALSO

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

DIAGNOSTICS

Exit status is 0 on success and 1 on error.  

HISTORY

The newfs_msdos command first appeared in Fx 3.0 .  

AUTHORS

An Robert Nordier Aq rnordier@FreeBSD.org .


 

Index

NAME
SYNOPSIS
DESCRIPTION
NOTES
EXAMPLES
SEE ALSO
DIAGNOSTICS
HISTORY
AUTHORS

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Time: 04:30:12 GMT, April 24, 2025