/sys/doc/ Documentation archive

MKFS(VIII)                   11/1/73                   MKFS(VIII)

     mkfs - construct a file system

     /etc/mkfs special proto

     Mkfs constructs a file system by writing on the special file
     special according to the directions found in  the  prototype
     file proto.  The prototype file contains tokens separated by
     spaces or new lines.  The first token is the name of a  file
     to  be  copied onto block zero as the bootstrap program (see
     boot procedures(VIII)).  The second token is a number spec-
     ifying  the  size  of the created file system.  Typically it
     will be the number of blocks on the device,  perhaps  dimin-
     ished  by  space for swapping.  The next token is the i-list
     size in blocks (remember there are 16  i-nodes  per  block).
     The  next  set  of tokens comprise the specification for the
     root file.  File specifications consist of tokens giving the
     mode, the user-id, the group id, and the initial contents of
     the file.  The syntax of the contents field depends  on  the

     The  mode  token  for  a  file is a 6 character string.  The
     first character specifies the type of the file.  (The  char-
     acters  -bcd  specify regular, block special, character spe-
     cial and directory files respectively.)  The second  charac-
     ter of the type is either u or - to specify set-user-id mode
     or not.  The third is g or - for the set-group-id mode.  The
     rest  of  the  mode is a three digit octal number giving the
     owner, group, and other  read,  write,  execute  permissions
     (see chmod(I)).

     Two  decimal number tokens come after the mode; they specify
     the user and group ID's of the owner of the file.

     If the file is a regular file, the next token is a  pathname
     whence the contents and size are copied.

     If  the file is a block or character special file, two deci-
     mal number tokens follow which give the major and minor  de-
     vice numbers.

     If  the file is a directory, mkfs makes the entries . and ..
     and then reads a list of names and (recursively) file speci-
     fications  for  the  entries  in the directory.  The scan is
     terminated with the token $.

     If the prototype file cannot be opened and its name consists
     of a string of digits, mkfs builds a file system with a sin-
     gle empty directory on it.  The size of the file  system  is
     the  value of proto interpreted as a decimal number.  The i-
     list size is the file system size divided  by  43  plus  the
     size  divided by 1000.  (This corresponds to an average size
     of three blocks per file for a 4000 block  file  system  and

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MKFS(VIII)                   11/1/73                   MKFS(VIII)

     six  blocks  per  file at 40,000.)  The boot program is left

     A sample prototype specification follows:

          4872 55
          d--777 3 1
          usr  d--777 3 1
               sh   ---755 3 1 /bin/sh
               ken  d--755 6 1
               b0   b--644 3 1 0 0
               c0   c--644 3 1 0 0

     file system(V), directory(V), boot procedures(VIII)

     It is not possible to initialize  a  file  larger  than  64K
     The size of the file system is restricted to 64K blocks.
     There should be some way to specify links.

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