1.\" Copyright (c) 1998 Robert Nordier 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in 11.\" the documentation and/or other materials provided with the 12.\" distribution. 13.\" 14.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS 15.\" OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 16.\" WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY 18.\" DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 20.\" GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 21.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER 22.\" IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 23.\" OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN 24.\" IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" 26.\" $FreeBSD$ 27.\" 28.Dd April 9, 2015 29.Dt NEWFS_MSDOS 8 30.Os 31.Sh NAME 32.Nm newfs_msdos 33.Nd construct a new MS-DOS (FAT) file system 34.Sh SYNOPSIS 35.Nm 36.Op Fl N 37.Op Fl @ Ar offset 38.Op Fl B Ar boot 39.Op Fl C Ar create-size 40.Op Fl F Ar FAT-type 41.Op Fl I Ar VolumeId 42.Op Fl L Ar label 43.Op Fl O Ar OEM 44.Op Fl S Ar sector-size 45.Op Fl a Ar FAT-size 46.Op Fl b Ar block-size 47.Op Fl c Ar cluster-size 48.Op Fl e Ar DirEnts 49.Op Fl f Ar format 50.Op Fl h Ar heads 51.Op Fl i Ar info 52.Op Fl k Ar backup 53.Op Fl m Ar media 54.Op Fl n Ar FATs 55.Op Fl o Ar hidden 56.Op Fl r Ar reserved 57.Op Fl s Ar total 58.Op Fl u Ar track-size 59.Ar special 60.Op Ar disktype 61.Sh DESCRIPTION 62The 63.Nm 64utility creates a FAT12, FAT16, or FAT32 file system on device or file named 65.Ar special , 66using 67.Xr disktab 5 68entry 69.Ar disktype 70to determine geometry, if required. 71.Pp 72If 73.Ar special 74does not contain a 75.Ar / 76and 77.Fl C 78is not used, it is assumed to be a device name and 79.Ar /dev/ 80is prepended to the name to construct the actual device name. 81To work a file in the current directory use 82.Ar ./filename 83.Pp 84The options are as follow: 85.Bl -tag -width indent 86.It Fl N 87Do not create a file system: just print out parameters. 88.It Fl @ Ar offset 89Build the filesystem at the specified offset in bytes in the device or file. 90A suffix s, k, m, g (lower or upper case) 91appended to the offset specifies that the 92number is in sectors, kilobytes, megabytes or gigabytes, respectively. 93.It Fl B Ar boot 94Get bootstrap from file. 95.It Fl C Ar create-size 96Create the image file with the specified size. 97A suffix character appended to the size is interpreted as for the 98.Fl @ 99option. 100The file is created by truncating any existing file with the same name and 101resizing it to the requested size. 102If the file system supports sparse files, the space occupied on disk may be 103smaller than the size specified as parameter. 104.It Fl F Ar FAT-type 105FAT type (one of 12, 16, or 32). 106.It Fl I Ar VolumeID 107Volume ID, a 32 bit number in decimal or hexadecimal (0x...) format. 108.It Fl L Ar label 109Volume label (up to 11 characters). 110The label should consist of 111only those characters permitted in regular DOS (8+3) filenames. 112.It Fl O Ar OEM 113OEM string (up to 8 characters). 114The default is 115.Qq Li "BSD4.4 " . 116.It Fl S Ar sector-size 117Number of bytes per sector. 118Acceptable values are powers of 2 119in the range 512 through 32768, inclusive. 120.It Fl a Ar FAT-size 121Number of sectors per FAT. 122.It Fl b Ar block-size 123File system block size (bytes per cluster). 124This should resolve to an 125acceptable number of sectors per cluster (see below). 126.It Fl c Ar cluster-size 127Sectors per cluster. 128Acceptable values are powers of 2 in the range 1291 through 128. 130If the block or cluster size are not specified, the code 131uses a cluster between 512 bytes and 32K depending on 132the filesystem size. 133.It Fl e Ar DirEnts 134Number of root directory entries (FAT12 and FAT16 only). 135.It Fl f Ar format 136Specify a standard (floppy disk) format. 137The standard formats 138are (capacities in kilobytes): 160, 180, 320, 360, 640, 720, 1200, 1391232, 1440, 2880. 140.It Fl h Ar heads 141Number of drive heads. 142.It Fl i Ar info 143Location of the file system info sector (FAT32 only). 144A value of 0xffff signifies no info sector. 145.It Fl k Ar backup 146Location of the backup boot sector (FAT32 only). 147A value 148of 0xffff signifies no backup sector. 149.It Fl m Ar media 150Media descriptor (acceptable range 0xf0 to 0xff). 151.It Fl n Ar FATs 152Number of FATs. 153Acceptable values are 1 to 16 inclusive. 154The default 155is 2. 156.It Fl o Ar hidden 157Number of hidden sectors. 158.It Fl r Ar reserved 159Number of reserved sectors. 160.It Fl s Ar total 161File system size. 162.It Fl u Ar track-size 163Number of sectors per track. 164.El 165.Sh NOTES 166If some parameters (e.g. size, number of sectors, etc.) are not specified 167through options or disktype, the program tries to generate them automatically. 168In particular, the size is determined as the device or file size minus the 169offset specified with the 170.Fl @ 171option. 172When the geometry is not available, it is assumed to be 63 sectors, 255 heads. 173The size is then rounded to become a multiple of the track size and avoid 174complaints by some filesystem code. 175.Pp 176FAT file system parameters occupy a "Boot Sector BPB (BIOS Parameter 177Block)" in the first of the "reserved" sectors which precede the actual 178file system. 179For reference purposes, this structure is presented 180below. 181.Bd -literal 182struct bsbpb { 183 uint16_t bpbBytesPerSec; /* [-S] bytes per sector */ 184 uint8_t bpbSecPerClust; /* [-c] sectors per cluster */ 185 uint16_t bpbResSectors; /* [-r] reserved sectors */ 186 uint8_t bpbFATs; /* [-n] number of FATs */ 187 uint16_t bpbRootDirEnts; /* [-e] root directory entries */ 188 uint16_t bpbSectors; /* [-s] total sectors */ 189 uint8_t bpbMedia; /* [-m] media descriptor */ 190 uint16_t bpbFATsecs; /* [-a] sectors per FAT */ 191 uint16_t bpbSecPerTrack; /* [-u] sectors per track */ 192 uint16_t bpbHeads; /* [-h] drive heads */ 193 uint32_t bpbHiddenSecs; /* [-o] hidden sectors */ 194 uint32_t bpbHugeSectors; /* [-s] big total sectors */ 195}; 196/* FAT32 extensions */ 197struct bsxbpb { 198 uint32_t bpbBigFATsecs; /* [-a] big sectors per FAT */ 199 uint16_t bpbExtFlags; /* control flags */ 200 uint16_t bpbFSVers; /* file system version */ 201 uint32_t bpbRootClust; /* root directory start cluster */ 202 uint16_t bpbFSInfo; /* [-i] file system info sector */ 203 uint16_t bpbBackup; /* [-k] backup boot sector */ 204}; 205.Ed 206.Sh LIMITATION 207The maximum file size is 4GB, even if the file system itself is bigger. 208.Sh EXIT STATUS 209Exit status is 0 on success and 1 on error. 210.Sh EXAMPLES 211Create a file system, using default parameters, on 212.Pa /dev/ada0s1 : 213.Bd -literal -offset indent 214newfs_msdos /dev/ada0s1 215.Ed 216.Pp 217Create a standard 1.44M file system, with volume label 218.Ar foo , 219on 220.Pa /dev/fd0 : 221.Bd -literal -offset indent 222newfs_msdos -f 1440 -L foo fd0 223.Ed 224.Pp 225Create a 30MB image file, with the FAT partition starting 22663 sectors within the image file: 227.Bd -literal -offset indent 228newfs_msdos -C 30M -@63s ./somefile 229.Ed 230.Sh SEE ALSO 231.Xr gpart 8 , 232.Xr newfs 8 233.Sh HISTORY 234The 235.Nm 236utility first appeared in 237.Fx 3.0 . 238.Sh AUTHORS 239.An Robert Nordier Aq Mt rnordier@FreeBSD.org 240