NAME | SYNOPSIS | DESCRIPTION | FILES | ATTRIBUTES | SEE ALSO
newfs is a target utility.
The newfs command replaces the now obsolete mkfs(1M) program. Before running newfs the disk must be labeled using disklabel (1M) .
The newfs command builds a file system on the special device specified, taking the defaults from the information on the disk label. Typically, the defaults are reasonable, however newfs has numerous options to allow the defaults to be selectively overridden.
The following options define the general layout policies:
Causes the file system parameters to be printed out (without creating the file system)
This specifies the maximum number of contiguous blocks that will be laid out before forcing a rotational delay (see the -d option). The default value is one
The block size of the file system, in bytes
The number of cylinders per cylinder group in a file system. The default value is 16
This specifies the expected time (in milliseconds) needed to service a transfer completion interrupt and initiate a new transfer on the same disk. The default is 4 milliseconds
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 approximately one quarter of the total blocks in a cylinder group
The fragment size of the file system in bytes. The default is 1024 bytes.
Specify the density of inodes in the file system. The default is to create an inode for every (4 * frag-size) 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.
The percentage of space reserved from normal users; the minimum free space threshold. The default value used is defined by MINFREE from <ufs/ffs/fs.h>, currently 8%.
Optimization preference ``space'' or ``time''. The file system can be instructed either 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
The size of the file system, in sectors
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 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 fsck to find the alternate superblocks if the standard superblock is lost.
The size of a sector in bytes (rarely anything other than 512)
sector 0 skew , per track Used to describe fluctuations 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
Used to describe fluctuations in the media format to compensate for a slow controller. Interleave is the physical sector interleave on each track, specified as the denominator of the ratio: sectors read/sectors passed over. Thus an interleave of 1/1 means contiguous layout, while 1/2 means logical sector 0 is separated by one sector from logical sector 1
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 as they are not available to the file system for data allocation
The speed of the disk in revolutions per minute
The number of tracks/cylinder available for data allocation by the file system
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 -p option)
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 of the last track of each cylinder as they are not available to the file system for data allocation
disktab(4CC), disklabel(1M)
See attributes(5) for descriptions of the following attributes:
ATTRIBUTE TYPE | ATTRIBUTE VALUE |
---|---|
Interface Stability | Evolving |
NAME | SYNOPSIS | DESCRIPTION | FILES | ATTRIBUTES | SEE ALSO