MKFS(VIII) 11/1/73 MKFS(VIII)
NAME
mkfs - construct a file system
SYNOPSIS
/etc/mkfs special proto
DESCRIPTION
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
specifying the size of the created file system. Typically
it will be the number of blocks on the device, perhaps
diminished 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 mode.
The mode token for a file is a 6 character string. The
first character specifies the type of the file. (The
characters -bcd specify regular, block special, character
special and directory files respectively.) The second
character 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
decimal number tokens follow which give the major and minor
device numbers.
If the file is a directory, mkfs makes the entries . and ..
and then reads a list of names and (recursively) file
specifications 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
single 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
six blocks per file at 40,000.) The boot program is left
uninitialized.
A sample prototype specification follows:
/usr/mdec/uboot
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
$
$
SEE ALSO
file system (V), directory (V), boot procedures (VIII)
BUGS
It is not possible to initialize a file larger than 64K
bytes.
The size of the file system is restricted to 64K blocks.
There should be some way to specify links.