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MKFS(8)                     System Manager's Manual                    MKFS(8)



NAME
       mkfs - construct a file system

SYNOPSIS
       /etc/mkfs  special size [ nsect ] [ ntrack ] [ blksize ] [ fragsize ] [
       ncpg ] [ minfree ] [ rps ]

DESCRIPTION
       N.B.: file system are normally created with the newfs(8) command.

       Mkfs constructs a file system by writing on the special  file  special.
       The  numeric  size  specifies the number of sectors in the file system.
       Mkfs builds a file system with a root directory and a lost+found direc-
       tory.   (see fsck(8)) The number of i-nodes is calculated as a function
       of the file system size.  No boot program is initialized by  mkfs  (see
       newfs(8).)

       The  optional  arguments allow fine tune control over the parameters of
       the file system.  Nsect specify the number of sectors per track on  the
       disk.   Ntrack  specify  the number of tracks per cylinder on the disk.
       Blksize gives the primary block size for files on the file system.   It
       must be a power of two, currently selected from 4096 or 8192.  Fragsize
       gives the fragment size for files on the  file  system.   The  fragsize
       represents  the smallest amount of disk space that will be allocated to
       a file.  It must be a power of two currently selected  from  the  range
       512  to 8192.  Ncpg specifies the number of disk cylinders per cylinder
       group.  This number must be in the range 1 to  32.   Minfree  specifies
       the  minimum percentage of free disk space allowed.  Once the file sys-
       tem capacity reaches this threshold, only the super-user is allowed  to
       allocate  disk  blocks.   The default value is 10%.  If a disk does not
       revolve at 60 revolutions per second, the rps parameter may  be  speci-
       fied.   Users  with special demands for their file systems are referred
       to the paper cited below for a discussion of  the  tradeoffs  in  using
       different configurations.

SEE ALSO
       fs(5), dir(5), fsck(8), newfs(8), tunefs(8)

       McKusick, Joy, Leffler; "A Fast File System for Unix", Computer Systems
       Research Group, Dept of EECS, Berkeley,  CA  94720;  TR  #7,  September
       1982.

BUGS
       There should be some way to specify bad blocks.



4th Berkeley Distribution         10 May 1981                          MKFS(8)