.\" Copyright (c) 1983, 1987, 1991, 1993, 1994 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)newfs.8 8.6 (Berkeley) 5/3/95 .\" .Dd May 3, 1995 .Dt NEWFS 8 .Os BSD 4.2 .Sh NAME .Nm newfs .Nd construct a new file system .Sh SYNOPSIS .Nm newfs .Op Fl NO .Op Fl S Ar sector-size .Op Fl T Ar disktype .Op Fl a Ar maxcontig .Op Fl b Ar block-size .Op Fl c Ar cylinders .Op Fl d Ar rotdelay .Op Fl e Ar maxbpg .Op Fl f Ar frag-size .Op Fl i Ar bytes .Op Fl k Ar skew .Op Fl l Ar interleave .Op Fl m Ar free space .Op Fl n Ar rotational positions .Op Fl o Ar optimization .Op Fl p Ar sectors .Op Fl r Ar revolutions .Op Fl s Ar size .Op Fl t Ar tracks .Op Fl u Ar sectors .Op Fl x Ar sectors .Ar special .Sh DESCRIPTION .Nm Newfs replaces the more obtuse .Xr mkfs 8 program. Before running .Nm newfs the disk must be labeled using .Xr disklabel 8 . .Nm Newfs builds a file system on the specified special device basing its defaults on the information in the disk label. Typically the defaults are reasonable, however .Nm newfs has numerous options to allow the defaults to be selectively overridden. .Pp The following options define the general layout policies. .Bl -tag -width Fl .It Fl N Causes the file system parameters to be printed out without really creating the file system. .It Fl O Creates a 4.3BSD format filesystem. This options is primarily used to build root filesystems that can be understood by older boot ROMs. .It Fl T Uses information for the specified disk from .Pa /etc/disktab instead of trying to get the information from a disklabel. .It Fl a Ar maxcontig This specifies the maximum number of contiguous blocks that will be laid out before forcing a rotational delay (see the .Fl d option). The default value is one. See .Xr tunefs 8 for more details on how to set this option. .It Fl b Ar block-size The block size of the file system, in bytes. .It Fl c Ar #cylinders/group The number of cylinders per cylinder group in a file system. The default value is 16. .It Fl d Ar rotdelay This specifies the expected time (in milliseconds) to service a transfer completion interrupt and initiate a new transfer on the same disk. The default is 4 milliseconds. See .Xr tunefs 8 for more details on how to set this option. .ne 1i .It Fl e Ar maxbpg This indicates the maximum number of blocks any single file can allocate out of a cylinder group before it is forced to begin allocating blocks from another cylinder group. The default is about one quarter of the total blocks in a cylinder group. See .Xr tunefs 8 for more details on how to set this option. .It Fl f Ar frag-size The fragment size of the file system in bytes. .It Fl i Ar number of bytes per inode This specifies the density of inodes in the file system. The default is to create an inode for each 2048 bytes of data space. If fewer inodes are desired, a larger number should be used; to create more inodes a smaller number should be given. .It Fl m Ar free space \&% The percentage of space reserved from normal users; the minimum free space threshold. The default value used is 10%. See .Xr tunefs 8 for more details on how to set this option. .It Fl n Ar rotational\ positions Determines how many rotational time slots there are in one revolution of the disk. .It Fl o Ar optimization\ preference .Pq ``space'' or ``time'' The file system can either be instructed to try to minimize the time spent allocating blocks, or to try to minimize the space fragmentation on the disk. If the value of minfree (see above) is less than 10%, the default is to optimize for space; if the value of minfree is greater than or equal to 10%, the default is to optimize for time. See .Xr tunefs 8 for more details on how to set this option. .It Fl s Ar size The size of the file system in sectors. .El .Pp The following options override the standard sizes for the disk geometry. Their default values are taken from the disk label. Changing these defaults is useful only when using .Nm newfs to build a file system whose raw image will eventually be used on a different type of disk than the one on which it is initially created (for example on a write-once disk). Note that changing any of these values from their defaults will make it impossible for .Xr fsck to find the alternate superblocks if the standard superblock is lost. .Bl -tag -width Fl .It Fl S Ar sector-size The size of a sector in bytes (almost never anything but 512). .It Fl k Ar sector \&0 skew , per track Used to describe perturbations in the media format to compensate for a slow controller. Track skew is the offset of sector 0 on track N relative to sector 0 on track N-1 on the same cylinder. .It Fl l Ar hardware sector interleave Used to describe perturbations in the media format to compensate for a slow controller. Interleave is physical sector interleave on each track, specified as the denominator of the ratio: .Dl sectors read/sectors passed over Thus an interleave of 1/1 implies contiguous layout, while 1/2 implies logical sector 0 is separated by one sector from logical sector 1. .It Fl p Ar spare sectors per track Spare sectors (bad sector replacements) are physical sectors that occupy space at the end of each track. They are not counted as part of the sectors/track .Pq Fl u since they are not available to the file system for data allocation. .It Fl r Ar revolutions/minute The speed of the disk in revolutions per minute. .ne 1i .It Fl t Ar #tracks/cylinder The number of tracks/cylinder available for data allocation by the file system. .It Fl u Ar sectors/track The number of sectors per track available for data allocation by the file system. This does not include sectors reserved at the end of each track for bad block replacement (see the .Fl p option.) .It Fl x Ar spare sectors per cylinder Spare sectors (bad sector replacements) are physical sectors that occupy space at the end of the last track in the cylinder. They are deducted from the sectors/track .Pq Fl u of the last track of each cylinder since they are not available to the file system for data allocation. .El .Pp .Sh SEE ALSO .Xr fs 5 , .Xr dumpfs 8 , .Xr fdisk 8 , .Xr fsck 8 , .Xr mount 8 , .Xr pdisk 8 , .Xr tunefs 8 .Rs .%A M. McKusick .%A W. Joy .%A S. Leffler .%A R. Fabry .%T A Fast File System for UNIX , .%J ACM Transactions on Computer Systems 2 .%V 3 .%P pp 181-197 .%D August 1984 .%O (reprinted in the BSD System Manager's Manual) .Re .Sh HISTORY The .Nm command appeared in .Bx 4.2 .