1NEWFS(8) 386BSD System Manager's Manual NEWFS(8) 2 3NNAAMMEE 4 nneewwffss - construct a new file system 5 6SSYYNNOOPPSSIISS 7 nneewwffss [--NN] [_n_e_w_f_s-_o_p_t_i_o_n_s] _s_p_e_c_i_a_l 8 9DDEESSCCRRIIPPTTIIOONN 10 NNeewwffss replaces the more obtuse mkfs(8) program. Before running nneewwffss the 11 disk must be labeled using disklabel(8). NNeewwffss builds a file system on 12 the specified special device basing its defaults on the information in 13 the disk label. Typically the defaults are reasonable, however nneewwffss has 14 numerous options to allow the defaults to be selectively overridden. 15 16 In addition, this program is used internally by the system. MMoouunntt__mmffss is 17 used to build a file system in virtual memory and then mount it on a 18 specified node. MMoouunntt__mmffss exits and the contents of the file system are 19 lost when the file system is unmounted. If mmoouunntt__mmffss is sent a signal 20 while running, for example during system shutdown, it will attempt to 21 unmount its corresponding file system. The parameters to mmoouunntt__mmffss are 22 the same as those to nneewwffss. The special file is only used to read the 23 disk label which provides a set of configuration parameters for the 24 memory based file system. The special file is typically that of the 25 primary swap area, since that is where the file system will be backed up 26 when free memory gets low and the memory supporting the file system has 27 to be paged. 28 29 The following options define the general layout policies. 30 31 --NN Causes the file system parameters to be printed out without 32 really creating the file system. 33 34 --bb _b_l_o_c_k-_s_i_z_e 35 The block size of the file system in bytes. 36 37 --ff _f_r_a_g-_s_i_z_e 38 The fragment size of the file system in bytes. 39 40 --mm _f_r_e_e _s_p_a_c_e % 41 The percentage of space reserved from normal users; the 42 minimum free space threshold. The default value used is 10%. 43 See tunefs(8) for more details on how to set this option. 44 45 --oo _o_p_t_i_m_i_z_a_t_i_o_n _p_r_e_f_e_r_e_n_c_e 46 (``space'' or ``time'') The file system can either be 47 instructed to try to minimize the time spent allocating 48 blocks, or to try to minimize the space fragmentation on the 49 disk. If the value of minfree (see above) is less than 10%, 50 the default is to optimize for space; if the value of minfree 51 greater than or equal to 10%, the default is to optimize for 52 time. See tunefs(8) for more details on how to set this 53 option. 54 55 --aa _m_a_x_c_o_n_t_i_g 56 This specifies the maximum number of contiguous blocks that 57 will be laid out before forcing a rotational delay (see --dd 58 below). The default value is one. See tunefs(8) for more 59 details on how to set this option. 60 61 --dd _r_o_t_d_e_l_a_y 62 This specifies the expected time (in milliseconds) to service 63 a transfer completion interrupt and initiate a new transfer 64 on the same disk. The default is 4 milliseconds. See 65 66 tunefs(8) for more details on how to set this option. 67 68 --ee _m_a_x_b_p_g This indicates the maximum number of blocks any single file 69 can allocate out of a cylinder group before it is forced to 70 begin allocating blocks from another cylinder group. The 71 default is about one quarter of the total blocks in a 72 cylinder group. See tunefs(8) for more details on how to set 73 this option. 74 75 --ii _n_u_m_b_e_r _o_f _b_y_t_e_s _p_e_r _i_n_o_d_e 76 This specifies the density of inodes in the file system. The 77 default is to create an inode for each 2048 bytes of data 78 space. If fewer inodes are desired, a larger number should 79 be used; to create more inodes a smaller number should be 80 given. 81 82 --cc #_c_y_l_i_n_d_e_r_s/_g_r_o_u_p 83 The number of cylinders per cylinder group in a file system. 84 The default value used is 16. 85 86 --ss _s_i_z_e The size of the file system in sectors. 87 88 The following options override the standard sizes for the 89 disk geometry. Their default values are taken from the disk 90 label. Changing these defaults is useful only when using 91 nneewwffss to build a file system whose raw image will eventually 92 be used on a different type of disk than the one on which it 93 is initially created (for example on a write-once disk). 94 Note that changing any of these values from their defaults 95 will make it impossible for fsck to find the alternate 96 superblocks if the standard super block is lost. 97 98 --rr _r_e_v_o_l_u_t_i_o_n_s/_m_i_n_u_t_e 99 The speed of the disk in revolutions per minute. 100 101 --SS _s_e_c_t_o_r-_s_i_z_e 102 The size of a sector in bytes (almost never anything but 103 512). 104 105 --uu _s_e_c_t_o_r_s/_t_r_a_c_k 106 The number of sectors per track available for data allocation 107 by the file system. This does not include sectors reserved 108 at the end of each track for bad block replacement (see --pp 109 below). 110 111 --tt #_t_r_a_c_k_s/_c_y_l_i_n_d_e_r 112 The number of tracks/cylinder available for data allocation 113 by the file system. 114 115 --pp _s_p_a_r_e _s_e_c_t_o_r_s _p_e_r _t_r_a_c_k 116 Spare sectors (bad sector replacements) are physical sectors 117 that occupy space at the end of each track. They are not 118 counted as part of the sectors/track (--uu) since they are not 119 available to the file system for data allocation. 120 121 --xx _s_p_a_r_e _s_e_c_t_o_r_s _p_e_r _c_y_l_i_n_d_e_r 122 Spare sectors (bad sector replacements) are physical sectors 123 that occupy space at the end of the last track in the 124 cylinder. They are deducted from the sectors/track (--uu) of 125 the last track of each cylinder since they are not available 126 to the file system for data allocation. 127 128 --ll _h_a_r_d_w_a_r_e _s_e_c_t_o_r _i_n_t_e_r_l_e_a_v_e 129 Used to describe perturbations in the media format to 130 compensate for a slow controller. Interleave is physical 131 sector interleave on each track, specified as the denominator 132 of the ratio: 133 sectors read/sectors passed over 134 Thus an interleave of 1/1 implies contiguous layout, while 135 1/2 implies logical sector 0 is separated by one sector from 136 logical sector 1. 137 138 --kk _s_e_c_t_o_r _0 _s_k_e_w, _p_e_r _t_r_a_c_k 139 Used to describe perturbations in the media format to 140 compensate for a slow controller. Track skew is the offset 141 of sector 0 on track N relative to sector 0 on track N-1 on 142 the same cylinder. 143 144 The following option applies only to mmoouunntt__mmffss. 145 146 --FF _m_o_u_n_t _f_l_a_g_s 147 Used to pass in a decimal numeric value to be passed as mount 148 flags when running as a memory based file system. This 149 option is primarily intended for use when mmoouunntt__mmffss is 150 started by the mount(8) command. 151 152SSEEEE AALLSSOO 153 disktab(5), fs(5), disklabel(8), diskpart(8), fsck(8), format(8), 154 tunefs(8) 155 156 M. McKusick, W. Joy, S. Leffler, and R. Fabry, "A Fast File System for 157 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 158 1984, (reprinted in the BSD System Manager's Manual). 159 160HHIISSTTOORRYY 161 The nneewwffss command appeared in 4.2BSD. 162 1634.2 Berkeley Distribution March 16, 1991 3 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199