mkfs - make a file system
mkfs [-t type] [-i inodes] [-b bpi] [-p priority] [-TDL] device [size]
Mkfs make a Minix file system on a the block special device, or prepares
the device for use as a paging device.
This mkfs is really a forerunner to mkfs1 through mkfs2f, see mkfs1(1)
for a more details.
Before mkfs calls any of the other programs to do the real work, it first
checks if device is mounted, because touching a mounted file system will
confuse the system.
Unlike the other programs the size argument is optional. Mkfs will do a
binary search for the end of the device to determine its size if not
given. You can specify a size to mkfs if you want to make a small file
system, or if you are using an old 360k PC drive whose size can't be
sensed automatically. (Or if you want to use a proto file, which is
accepted if size is not a number.)
The maximum file system size is 64 Mb for the V1 types, and 1 Gb for V2.
Make a file system of type 1, 2, 1f, 2f, a swap device (swap), or
add swap to the second half of a device (+swap). If the type is not
given then the fstab is searched for a type, otherwise an error is
reported. The odd +swap type is used to initialize an area behind a
file system as swap space. First you make a file system on a device
that is smaller than the device allows. (By using a smaller size
argument.) Then you use +swap to mark the rest of the device as
Make a file system with exacly this many inodes. Use this option if
you need a certain number of inodes, like on the root file system
for all the device files. Minix file systems can't have more than
65535 inodes, so the number of inodes is truncated to this number.
Sets the average number of bytes per inode. The number of inodes is
computed by dividing the size of the device by this ratio. By
default -b 3072 is assumed for small file systems, increasing to 4
kb at 8 Mb, 5 kb at 16 Mb, 6 kb at 32 Mb, 7 kb at 64 Mb and 8 kb at
128 Mb and above. (It is assumed that larger file systems have
The priority of a swap device tells which device should be preferred
for swapping. Highest priority wins. Priority is a signed number,
by default 0.
-TDL These options are passed on to the real mkfs program in lowercase.
mkfs1(1), fstab(5), mount(1).
$ mkfs -t 2f /dev/fd0
/dev/fd0: V2 flex file system, 1440 kilobytes, 480 inodes, 3072
Four different programs with just minor differences is a bug in itself.
The V1 file systems lack accessed and inode changed times, and are too
small for serious use. New file systems should be V2.
A V3 file system with more inodes is badly needed.
Kees J. Bot (email@example.com)