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33 .Nd construct a new MS-DOS (FAT) file system
39 .Op Fl C Ar create-size
44 .Op Fl S Ar sector-size
47 .Op Fl b Ar block-size
48 .Op Fl c Ar cluster-size
59 .Op Fl u Ar track-size
65 utility creates a FAT12, FAT16, or FAT32 file system on device or file named
71 to determine geometry, if required.
79 is not used, it is assumed to be a device name and
81 is prepended to the name to construct the actual device name.
82 To work a file in the current directory use
85 The options are as follow:
86 .Bl -tag -width indent
88 Do not create a file system: just print out parameters.
90 Build the filesystem at the specified offset in bytes in the device or file.
91 A suffix s, k, m, g (lower or upper case)
92 appended to the offset specifies that the
93 number is in sectors, kilobytes, megabytes or gigabytes, respectively.
95 Get bootstrap from file.
96 .It Fl C Ar create-size
97 Create the image file with the specified size.
98 A suffix character appended to the size is interpreted as for the
101 The file is created by truncating any existing file with the same name and
102 resizing it to the requested size.
103 If the file system supports sparse files, the space occupied on disk may be
104 smaller than the size specified as parameter.
106 FAT type (one of 12, 16, or 32).
108 Volume ID, a 32 bit number in decimal or hexadecimal (0x...) format.
110 Volume label (up to 11 characters).
111 The label should consist of
112 only those characters permitted in regular DOS (8+3) filenames.
114 OEM string (up to 8 characters).
117 .It Fl S Ar sector-size
118 Number of bytes per sector.
119 Acceptable values are powers of 2
120 in the range 512 through 32768, inclusive.
121 .It Fl T Ar timestamp
122 Create the filesystem as though the current time is
124 The default filesystem volume ID is derived from the time.
126 can be a pathname (where the timestamp is derived from
127 that file) or an integer value interpreted
128 as the number of seconds since the Epoch.
130 Number of sectors per FAT.
131 .It Fl b Ar block-size
132 File system block size (bytes per cluster).
133 This should resolve to an
134 acceptable number of sectors per cluster (see below).
135 .It Fl c Ar cluster-size
137 Acceptable values are powers of 2 in the range
139 If the block or cluster size are not specified, the code
140 uses a cluster between 512 bytes and 32K depending on
143 Number of root directory entries (FAT12 and FAT16 only).
145 Specify a standard (floppy disk) format.
147 are (capacities in kilobytes): 160, 180, 320, 360, 640, 720, 1200,
150 Number of drive heads.
152 Location of the file system info sector (FAT32 only).
153 A value of 0xffff signifies no info sector.
155 Location of the backup boot sector (FAT32 only).
157 of 0xffff signifies no backup sector.
159 Media descriptor (acceptable range 0xf0 to 0xff).
162 Acceptable values are 1 to 16 inclusive.
166 Number of hidden sectors.
168 Number of reserved sectors.
171 .It Fl u Ar track-size
172 Number of sectors per track.
175 If some parameters (e.g., size, number of sectors, etc.) are not specified
176 through options or disktype, the program tries to generate them automatically.
177 In particular, the size is determined as the device or file size minus the
178 offset specified with the
181 When the geometry is not available, it is assumed to be 63 sectors, 255 heads.
182 The size is then rounded to become a multiple of the track size and avoid
183 complaints by some filesystem code.
185 FAT file system parameters occupy a "Boot Sector BPB (BIOS Parameter
186 Block)" in the first of the "reserved" sectors which precede the actual
188 For reference purposes, this structure is presented
192 uint16_t bpbBytesPerSec; /* [-S] bytes per sector */
193 uint8_t bpbSecPerClust; /* [-c] sectors per cluster */
194 uint16_t bpbResSectors; /* [-r] reserved sectors */
195 uint8_t bpbFATs; /* [-n] number of FATs */
196 uint16_t bpbRootDirEnts; /* [-e] root directory entries */
197 uint16_t bpbSectors; /* [-s] total sectors */
198 uint8_t bpbMedia; /* [-m] media descriptor */
199 uint16_t bpbFATsecs; /* [-a] sectors per FAT */
200 uint16_t bpbSecPerTrack; /* [-u] sectors per track */
201 uint16_t bpbHeads; /* [-h] drive heads */
202 uint32_t bpbHiddenSecs; /* [-o] hidden sectors */
203 uint32_t bpbHugeSectors; /* [-s] big total sectors */
205 /* FAT32 extensions */
207 uint32_t bpbBigFATsecs; /* [-a] big sectors per FAT */
208 uint16_t bpbExtFlags; /* control flags */
209 uint16_t bpbFSVers; /* file system version */
210 uint32_t bpbRootClust; /* root directory start cluster */
211 uint16_t bpbFSInfo; /* [-i] file system info sector */
212 uint16_t bpbBackup; /* [-k] backup boot sector */
216 The maximum file size is 4GB, even if the file system itself is bigger.
218 Exit status is 0 on success and 1 on error.
220 Create a file system, using default parameters, on
222 .Bd -literal -offset indent
223 newfs_msdos /dev/ada0s1
226 Create a standard 1.44M file system, with volume label
230 .Bd -literal -offset indent
231 newfs_msdos -f 1440 -L foo fd0
234 Create a 30MB image file, with the FAT partition starting
235 63 sectors within the image file:
236 .Bd -literal -offset indent
237 newfs_msdos -C 30M -@63s ./somefile
245 utility first appeared in
248 .An Robert Nordier Aq Mt rnordier@FreeBSD.org