4.3BSD-Reno/share/man/cat8/newfs.0
NEWFS(8) 1990 NEWFS(8)
NNAAMMEE
newfs, mfs - construct a new file system
SSYYNNOOPPSSIISS
nneewwffss [ --NN ] [ nneewwffss--ooppttiioonnss ] ssppeecciiaall
mmffss [ --FF mount_flags ] [ nneewwffss--ooppttiioonnss ] ssppeecciiaall nnooddee
DDEESSCCRRIIPPTTIIOONN
_N_e_w_f_s replaces the more obtuse _m_k_f_s(8) program. Before run-
ning _n_e_w_f_s or _m_f_s, the disk must be labeled using _d_i_s_k_l_a_-
_b_e_l(8). _N_e_w_f_s 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 _n_e_w_f_s
has numerous options to allow the defaults to be selectively
overridden. The --NN option causes the file system parameters
to be printed out without really creating the file system.
_M_f_s is used to build a file system in virtual memory and
then mount it on a specified node. _M_f_s exits and the con-
tents of the file system are lost when the file system is
unmounted. If _m_f_s is sent a signal while running, for exam-
ple during system shutdown, it will attempt to unmount its
corresponding file system. The parameters to _m_f_s are the
same as those to _n_e_w_f_s. The special file is only used to
read the disk label which provides a set of configuration
parameters for the memory based file system. The special
file is typically that of the primary swap area, since that
is where the file system will be backed up when free memory
gets low and the memory supporting the file system has to be
paged.
The following options define the general layout policies.
--bb bblloocckk--ssiizzee
The block size of the file system in bytes.
--ff ffrraagg--ssiizzee
The fragment size of the file system in bytes.
--mm ffrreeee ssppaaccee %%
The percentage of space reserved from normal
users; the minimum free space threshold. The
default value used is 10%. See _t_u_n_e_f_s(8) for more
details on how to set this option.
--oo ooppttiimmiizzaattiioonn pprreeffeerreennccee ((````ssppaaccee'''' oorr ````ttiimmee''''))
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 greater than or equal to 10%,
Printed 7/27/90 June 1
NEWFS(8) 1990 NEWFS(8)
the default is to optimize for time. See
_t_u_n_e_f_s(8) for more details on how to set this
option.
--aa mmaaxxccoonnttiigg
This specifies the maximum number of contiguous
blocks that will be laid out before forcing a
rotational delay (see -d below). The default
value is one. See _t_u_n_e_f_s(8) for more details on
how to set this option.
--dd rroottddeellaayy
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 _t_u_n_e_f_s(8) for more
details on how to set this option.
--ee mmaaxxbbppgg 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 _t_u_n_e_f_s(8) for more details on how to
set this option.
--ii nnuummbbeerr ooff bbyytteess ppeerr iinnooddee
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.
--cc ##ccyylliinnddeerrss//ggrroouupp
The number of cylinders per cylinder group in a
file system. The default value used is 16.
--ss ssiizzee 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
_n_e_w_f_s 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 _f_s_c_k to find the alternate
superblocks if the standard super block is lost.
--rr rreevvoolluuttiioonnss//mmiinnuuttee
The speed of the disk in revolutions per minute.
Printed 7/27/90 June 2
NEWFS(8) 1990 NEWFS(8)
--SS sseeccttoorr--ssiizzee
The size of a sector in bytes (almost never any-
thing but 512).
--uu sseeccttoorrss//ttrraacckk
The number of sectors/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 --pp below).
--tt ##ttrraacckkss//ccyylliinnddeerr
The number of tracks/cylinder available for data
allocation by the file system.
--pp ssppaarree sseeccttoorrss ppeerr ttrraacckk
Spare sectors (bad sector replacements) are physi-
cal sectors that occupy space at the end of each
track. They are not counted as part of the
sectors/track (--uu) since they are not available to
the file system for data allocation.
--xx ssppaarree sseeccttoorrss ppeerr ccyylliinnddeerr
Spare sectors (bad sector replacements) are physi-
cal sectors that occupy space at the end of the
last track in the cylinder. They are deducted
from the sectors/track (--uu) of the last track of
each cylinder since they are not available to the
file system for data allocation.
--ll hhaarrddwwaarree sseeccttoorr iinntteerrlleeaavvee
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:
sectors read / sectors passed over
Thus an interleave of 1/1 implies contiguous lay-
out, while 1/2 implies logical sector 0 is
separated by one sector from logical sector 1.
--kk sseeccttoorr 00 sskkeeww,, ppeerr ttrraacckk
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.
The following option applies only to _m_f_s.
--FF mmoouunntt ffllaaggss
Used to pass in a decimal numeric value to be
passed as mount flags when running as a memory
based file system. This option is primarily
intended for use when _m_f_s is started by the
Printed 7/27/90 June 3
NEWFS(8) 1990 NEWFS(8)
_m_o_u_n_t(8) command.
SSEEEE AALLSSOO
disktab(5), fs(5), disklabel(8), diskpart(8), fsck(8), for-
mat(8), tunefs(8)
M. McKusick, W. Joy, S. Leffler, R. Fabry, ``A Fast File
System for UNIX'', _A_C_M _T_r_a_n_s_a_c_t_i_o_n_s _o_n _C_o_m_p_u_t_e_r _S_y_s_t_e_m_s _2,
3. pp 181-197, August 1984. (reprinted in the System
Manager's Manual, SMM:14)
Printed 7/27/90 June 4