1.\" Copyright (c) 1983, 1987, 1991, 1993, 1994 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)newfs.8 8.3 (Berkeley) 3/27/94 33.\" 34.Dd March 27, 1994 35.Dt NEWFS 8 36.Os BSD 4.2 37.Sh NAME 38.Nm newfs , 39.Nm mfs 40.Nd construct a new file system 41.Sh SYNOPSIS 42.Nm newfs 43.Op Fl NO 44.Op Fl S Ar sector-size 45.Op Fl a maxcontig 46.Op Fl b Ar block-size 47.Op Fl c Ar cylinders 48.Op Fl d Ar rotdelay 49.Op Fl e Ar maxbpg 50.Op Fl f Ar frag-size 51.Op Fl i Ar bytes 52.Op Fl k Ar skew 53.Op Fl l Ar interleave 54.Op Fl m Ar free space 55.Op Fl o Ar optimization 56.Op Fl p Ar sectors 57.Op Fl r Ar revolutions 58.Op Fl s Ar size 59.Op Fl t Ar tracks 60.Op Fl u Ar sectors 61.Op Fl x Ar sectors 62.Ar special 63.Nm mount_mfs 64.Op Fl N 65.Op Fl a maxcontig 66.Op Fl b Ar block-size 67.Op Fl c Ar cylinders 68.Op Fl d Ar rotdelay 69.Op Fl e Ar maxbpg 70.Op Fl f Ar frag-size 71.Op Fl i Ar bytes 72.Op Fl m Ar free space 73.Op Fl o Ar options 74.Op Fl s Ar size 75.Ar special node 76.Sh DESCRIPTION 77.Nm Newfs 78replaces the more obtuse 79.Xr mkfs 8 80program. 81Before running 82.Nm newfs 83or 84.Nm mount_mfs , 85the disk must be labeled using 86.Xr disklabel 8 . 87.Nm Newfs 88builds a file system on the specified special device 89basing its defaults on the information in the disk label. 90Typically the defaults are reasonable, however 91.Nm newfs 92has numerous options to allow the defaults to be selectively overridden. 93.Pp 94.Nm Mount_mfs 95is used to build a file system in virtual memory and then mount it 96on a specified node. 97.Nm Mount_mfs 98exits and the contents of the file system are lost 99when the file system is unmounted. 100If 101.Nm mount_mfs 102is sent a signal while running, 103for example during system shutdown, 104it will attempt to unmount its 105corresponding file system. 106The parameters to 107.Nm mount_mfs 108are the same as those to 109.Nm newfs . 110The special file is only used to read the disk label which provides 111a set of configuration parameters for the memory based file system. 112The special file is typically that of the primary swap area, 113since that is where the file system will be backed up when 114free memory gets low and the memory supporting 115the file system has to be paged. 116.Pp 117The following options define the general layout policies. 118.Bl -tag -width Fl 119.It Fl N 120Causes the file system parameters to be printed out 121without really creating the file system. 122.It Fl O 123Creates a 4.3BSD format filesystem. 124This options is primarily used to build root filesystems 125that can be understood by older boot ROMs. 126.It Fl a Ar maxcontig 127This specifies the maximum number of contiguous blocks that will be 128laid out before forcing a rotational delay (see the 129.Fl d 130option). 131The default value is one. 132See 133.Xr tunefs 8 134for more details on how to set this option. 135.It Fl b Ar block-size 136The block size of the file system, in bytes. 137.It Fl c Ar #cylinders/group 138The number of cylinders per cylinder group in a file system. 139The default value is 16. 140.It Fl d Ar rotdelay 141This specifies the expected time (in milliseconds) to service a transfer 142completion interrupt and initiate a new transfer on the same disk. 143The default is 4 milliseconds. 144See 145.Xr tunefs 8 146for more details on how to set this option. 147.It Fl e Ar maxbpg 148This indicates the maximum number of blocks any single file can 149allocate out of a cylinder group before it is forced to begin 150allocating blocks from another cylinder group. 151The default is about one quarter of the total blocks in a cylinder group. 152See 153.Xr tunefs 8 154for more details on how to set this option. 155.It Fl f Ar frag-size 156The fragment size of the file system in bytes. 157.It Fl i Ar number of bytes per inode 158This specifies the density of inodes in the file system. 159The default is to create an inode for each 2048 bytes of data space. 160If fewer inodes are desired, a larger number should be used; 161to create more inodes a smaller number should be given. 162.It Fl m Ar free space \&% 163The percentage of space reserved from normal users; the minimum free 164space threshold. 165The default value used is 10%. 166See 167.Xr tunefs 8 168for more details on how to set this option. 169.It Fl o Ar optimization\ preference 170.Pq ``space'' or ``time'' 171The file system can either be instructed to try to minimize the time spent 172allocating blocks, or to try to minimize the space fragmentation on the disk. 173If the value of minfree (see above) is less than 10%, 174the default is to optimize for space; 175if the value of minfree is greater than or equal to 10%, 176the default is to optimize for time. 177See 178.Xr tunefs 8 179for more details on how to set this option. 180.It Fl s Ar size 181The size of the file system in sectors. 182.El 183.Pp 184The following options override the standard sizes for the disk geometry. 185Their default values are taken from the disk label. 186Changing these defaults is useful only when using 187.Nm newfs 188to build a file system whose raw image will eventually be used on a 189different type of disk than the one on which it is initially created 190(for example on a write-once disk). 191Note that changing any of these values from their defaults will make 192it impossible for 193.Xr fsck 194to find the alternate superblocks if the standard superblock is lost. 195.Bl -tag -width Fl 196.It Fl S Ar sector-size 197The size of a sector in bytes (almost never anything but 512). 198.It Fl k Ar sector \&0 skew , per track 199Used to describe perturbations in the media format to compensate for 200a slow controller. 201Track skew is the offset of sector 0 on track N relative to sector 0 202on track N-1 on the same cylinder. 203.It Fl l Ar hardware sector interleave 204Used to describe perturbations in the media format to compensate for 205a slow controller. 206Interleave is physical sector interleave on each track, 207specified as the denominator of the ratio: 208.Dl sectors read/sectors passed over 209Thus an interleave of 1/1 implies contiguous layout, while 1/2 implies 210logical sector 0 is separated by one sector from logical sector 1. 211.It Fl p Ar spare sectors per track 212Spare sectors (bad sector replacements) are physical sectors that occupy 213space at the end of each track. 214They are not counted as part of the sectors/track 215.Pq Fl u 216since they are not available to the file system for data allocation. 217.It Fl r Ar revolutions/minute 218The speed of the disk in revolutions per minute. 219.It Fl t Ar #tracks/cylinder 220The number of tracks/cylinder available for data allocation by the file 221system. 222.It Fl u Ar sectors/track 223The number of sectors per track available for data allocation by the file 224system. 225This does not include sectors reserved at the end of each track for bad 226block replacement (see the 227.Fl p 228option.) 229.It Fl x Ar spare sectors per cylinder 230Spare sectors (bad sector replacements) are physical sectors that occupy 231space at the end of the last track in the cylinder. 232They are deducted from the sectors/track 233.Pq Fl u 234of the last track of each cylinder since they are not available to the file 235system for data allocation. 236.El 237.Pp 238The options to the 239.Nm mount_mfs 240command are as described for the 241.Nm newfs 242command, except for the 243.Fl o 244option. 245.Pp 246That option is as follows: 247.Bl -tag -width indent 248.It Fl o 249Options are specified with a 250.Fl o 251flag followed by a comma separated string of options. 252See the 253.Xr mount 8 254man page for possible options and their meanings. 255.El 256.Sh SEE ALSO 257.Xr disktab 5 , 258.Xr fs 5 , 259.Xr dumpfs 8 , 260.Xr disklabel 8 , 261.Xr diskpart 8 , 262.Xr fsck 8 , 263.Xr format 8 , 264.Xr mount 8 , 265.Xr tunefs 8 266.Rs 267.%A M. McKusick 268.%A W. Joy 269.%A S. Leffler 270.%A R. Fabry 271.%T A Fast File System for UNIX , 272.%J ACM Transactions on Computer Systems 2 273.%V 3 274.%P pp 181-197 275.%D August 1984 276.%O (reprinted in the BSD System Manager's Manual) 277.Re 278.Sh HISTORY 279The 280.Nm 281command appeared in 282.Bx 4.2 . 283