.\" Copyright (c) 1980 Regents of the University of California.
.\" All rights reserved.  The Berkeley software License Agreement
.\" specifies the terms and conditions for redistribution.
.\"
.\"	@(#)mkfs.8	6.3 (Berkeley) 5/21/86
.\"
.TH MKFS 8 "May 21, 1986"
.UC 4
.SH NAME
mkfs \- construct a file system
.SH SYNOPSIS
.B /etc/mkfs
[ \-N ]
special size
[ nsect
[ ntrack
[ blksize
[ fragsize
[ ncpg
[ minfree
[ rps
[ nbpi
[ opt ] ] ] ] ] ] ] ] ]
.SH DESCRIPTION
.B N.B.:
file system are normally created with the
.IR newfs (8)
command.
.PP
.I Mkfs
constructs a file system
by writing on the special file
.I special
unless the \-N flag has been specified.
The numeric size specifies the number of sectors in the file system.
.I Mkfs
builds a file system with a root directory and a
.I lost+found
directory.
(see 
.IR fsck (8))
The number of i-nodes is calculated as a function of the file system size.
No boot program is initialized by
.I mkfs
(see
.IR newfs (8).)
.PP
The optional arguments allow fine tune control over the
parameters of the file system.
.B Nsect
specify the number of sectors per track on the disk.
.B Ntrack 
specify the number of tracks per cylinder on the disk.
.B 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.
.B Fragsize
gives the fragment size for files on the file system.
The
.B 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.
.B Ncpg
specifies the number of disk cylinders per cylinder group.
This number must be in the range 1 to 32.
.B Minfree
specifies the minimum percentage of free disk space allowed.
Once the file system 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
.B rps
parameter may be specified.
If a file system will have more or less than the average number of
files the
.B nbpi
(number of bytes per inode) can be specified to increase or
decrease the number of inodes that are created.
Space or time optimization preference can be specified with
.B opt
values of ``s'' for space or ``t'' for time.
Users with special demands for their file systems are referred to
the paper cited below for a discussion of the tradeoffs in using
different configurations.
.SH "SEE ALSO"
fs(5),
dir(5),
fsck(8),
newfs(8),
tunefs(8)
.PP
M. McKusick, W. Joy, S. Leffler, R. Fabry,
``A Fast File System for UNIX'',
\fIACM Transactions on Computer Systems 2\fP, 3.
pp 181-197, August 1984.
(reprinted in the System Manager's Manual, SMM:14)
.SH BUGS
There should be some way to specify bad blocks.