MKFS(8) System Manager's Manual MKFS(8)
mkfs - construct a file system
/etc/mkfs special size [ nsect ] [ ntrack ] [ blksize ] [ fragsize ] [
ncpg ] [ minfree ] [ rps ]
N.B.: file system are normally created with the newfs(8) command.
Mkfs constructs a file system by writing on the special file special.
The numeric size specifies the number of sectors in the file system.
Mkfs builds a file system with a root directory and a lost+found direc-
tory. (see fsck(8)) The number of i-nodes is calculated as a function
of the file system size. No boot program is initialized by mkfs (see
The optional arguments allow fine tune control over the parameters of
the file system. Nsect specify the number of sectors per track on the
disk. Ntrack specify the number of tracks per cylinder on the disk.
Blksize gives the primary block size for files on the file system. It
must be a power of two, currently selected from 4096 or 8192. Fragsize
gives the fragment size for files on the file system. The fragsize
represents the smallest amount of disk space that will be allocated to
a file. It must be a power of two currently selected from the range
512 to 8192. Ncpg specifies the number of disk cylinders per cylinder
group. This number must be in the range 1 to 32. Minfree specifies
the minimum percentage of free disk space allowed. Once the file sys-
tem capacity reaches this threshold, only the super-user is allowed to
allocate disk blocks. The default value is 10%. If a disk does not
revolve at 60 revolutions per second, the rps parameter may be speci-
fied. Users with special demands for their file systems are referred
to the paper cited below for a discussion of the tradeoffs in using
fs(5), dir(5), fsck(8), newfs(8), tunefs(8)
McKusick, Joy, Leffler; "A Fast File System for Unix", Computer Systems
Research Group, Dept of EECS, Berkeley, CA 94720; TR #7, September
There should be some way to specify bad blocks.
4th Berkeley Distribution 10 May 1981 MKFS(8)