newfs_msdos(8) - NetBSD Manual Pages

Command: Section: Arch: Collection:  
NEWFS_MSDOS(8)          NetBSD System Manager's Manual          NEWFS_MSDOS(8)

newfs_msdos -- construct a new MS-DOS (FAT) file system
newfs_msdos [-N] [-@ offset] [-B boot] [-C create-size] [-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] [-T timestamp] [-u track-size] special [disktype]
The newfs_msdos utility creates a FAT12, FAT16, or FAT32 file system on device or file named special, using disktab(5) entry disktype to deter- mine geometry, if required. The options are as follow: -N Do not create a file system: just print out parameters. -@ offset Build the file system at the specified offset in bytes in the device or file. A suffix s, k, m, g (lower or upper case) appended to the offset specifies that the number is in sectors, kilobytes, megabytes or gigabytes, respectively. -B boot Get bootstrap from file. -C create-size Create the image file with the specified size. A suffix charac- ter appended to the size is interpreted as for the -@ option. The file is created by truncating any existing file with the same name, seeking just before the required size and writing a single 0 byte. As a consequence, the space occupied on disk may be smaller than the size specified as a parameter. -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. The default is "NO NAME". -O OEM OEM string (up to 8 characters). The default is "NetBSD". -S sector-size Number of bytes per sector. Acceptable values are powers of 2 in the range 512 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. If the block or cluster size are not speci- fied, the code uses a cluster between 512 bytes and 32K depending on the file system size. -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. -T AT&T UNIX timestamp Specify a timestamp to be used for file system creation so that it can be consistent for reproducible builds. The timestamp can be a pathname, where the timestamps are derived from that file, a parseable date for parsedate(3) (this option is not yet available in the tools build), or an integer value interpreted as the num- ber of seconds from the Epoch. -u track-size Number of sectors per track. If newfs_msdos receives a SIGINFO signal (see the status argument for stty(1)), a line will be written to the standard error output indicating the name of the device currently being formatted, the sector number being written, and the total number of sectors to be written.
If some parameters (e.g. size, number of sectors, etc.) are not specified through options or disktype, the program tries to generate them automati- cally. In particular, the size is determined as the device or file size minus the offset specified with the -@ option. When the geometry is not available, it is assumed to be 63 sectors, 255 heads. The size is then rounded to become a multiple of the track size and avoid complaints by some file system code. 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/rwd1a Create a file system, using default parameters, on /dev/rwd1a. newfs_msdos -f 1440 -L foo /dev/rfd0a Create a standard 1.44M file system, with volume label foo, on /dev/rfd0a. Create a 30MB image file, with the FAT partition starting 63 sectors within the image file: newfs_msdos -C 30M -@63s ./somefile
Exit status is 0 on success and 1 on error.
disktab(5), disklabel(8), fdisk(8), newfs(8)
A newfs_msdos utility appeared in FreeBSD 3.0. The newfs_msdos command first appeared in NetBSD 1.3.
Robert Nordier <>. NetBSD 9.3 February 16, 2017 NetBSD 9.3
Powered by man-cgi (2024-03-20). Maintained for NetBSD by Kimmo Suominen. Based on man-cgi by Panagiotis Christias.