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