MKFS(1M) (Essential Utilities) MKFS(1M)
NAME
mkfs - construct a file system
SYNOPSIS
/etc/mkfs special blocks[:i-nodes] [gap blocks/cyl]
/etc/mkfs special proto [gap blocks/cyl]
DESCRIPTION
mkfs constructs a file system by writing on the special file
using the values found in the remaining arguments of the
command line. The command waits 10 seconds before starting
to construct the file system. During this 10-second pause
the command can be aborted by entering a delete (DEL) or
whatever key the user has the interrupt key set to.
If the second argument is a string of digits, the size of
the file system is the value of blocks interpreted as a
decimal number. This is the number of physical (512 byte)
disk blocks the file system will occupy. If the number of
i-nodes is not given, the default is the number of logical
(1024 byte) blocks divided by 4. mkfs builds a file system
with a single empty directory on it. The boot program block
(block zero) is left uninitialized.
If the second argument is the name of a file that can be
opened, mkfs assumes it to be a prototype file proto, and
will take its directions from that file. The prototype file
contains tokens separated by spaces or new-lines. A sample
prototype specification follows (line numbers have been
added to aid in the explanation):
1. /stand/diskboot
2. 4872 110
3. d--777 3 1
4. usr d--777 3 1
5. sh ---755 3 1 /bin/sh
6. ken d--755 6 1
7. $
8. b0 b--644 3 1 0 0
9. c0 c--644 3 1 0 0
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MKFS(1M) (Essential Utilities) MKFS(1M)
10. $
11. $
Line 1 in the example is the name of a file to be copied
onto block zero as the bootstrap program.
Line 2 specifies the number of physical (512 byte) blocks
the file system is to occupy and the number of i-nodes in
the file system.
Lines 3-9 tell mkfs about files and directories to be
included in this file system.
Line 3 specifies the root directory.
lines 4-6 and 8-9 specifies other directories and files.
The $ on line 7 tells mkfs to end the branch of the file
system it is on, and continue from the next higher
directory. The $ on lines 10 and 11 end the process, since
no additional specifications follow.
File specifications give the mode, the user ID, the
group ID, and the initial contents of the file. Valid
syntax for the contents field depends on the first
character of the mode.
The mode for a file is specified by a 6-character string.
The first character specifies the type of the file. The
character range is -bcd to specify regular, block special,
character special and directory files respectively. The
second character of the mode 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 3 digit octal
number giving the owner, group, and other read, write,
execute permissions (see chmod(1)).
Two decimal number tokens come after the mode; they specify
the user and group IDs of the owner of the file.
If the file is a regular file, the next token of the
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MKFS(1M) (Essential Utilities) MKFS(1M)
specification may be a path name whence the contents and
size are copied. If the file is a block or character
special file, two decimal numbers 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. As noted above, the scan is terminated
with the token $.
The final argument in both forms of the command specifies
the rotational gap and the number of blocks/cyl. The
following values are recommended for the devices available
on the 3B2:
Device Gap Size Blks/Cyl
____________________________________________________
30M Hard Disk 10 90
72M Hard Disk 10 162 (CDC Wren II)
72aM Hard Disk 10 144 (Micropolis)
72bM Hard Disk 10 198 (Priam)
72cM Hard Disk 10 198 (Fujitsu)
Floppy Disk 1 18
If the gap and blocks/cyl are not specified or are
considered illegal values a default value of gap size 7 and
400 blocks/cyl is used.
FILES
/etc/vtoc/*
SEE ALSO
chmod(1) in the User's Reference Manual.
dir(4), fs(4) in the Programmer's Reference Manual.
BUGS
With a prototype file, it is not possible to copy in a file
larger than 64K bytes, nor is there a way to specify links.
The maximum number of i-nodes configurable is 65500.
Page 3 May 1989