NAME¶
mkfs.cramfs - make compressed ROM file system
SYNOPSIS¶
mkfs.cramfs [options]
directory file
DESCRIPTION¶
Files on cramfs file systems are zlib-compressed one page at a time to allow
random read access. The metadata is not compressed, but is expressed in a
terse representation that is more space-efficient than conventional file
systems.
The file system is intentionally read-only to simplify its design; random write
access for compressed files is difficult to implement. cramfs ships with a
utility (mkcramfs) to pack files into new cramfs images.
File sizes are limited to less than 16 MB.
Maximum file system size is a little under 272 MB. (The last file on the
file system must begin before the 256 MB block, but can extend past
it.)
ARGUMENTS¶
The
directory is simply the root of the directory tree that we want to
generate a compressed filesystem out of.
The
file will contain the cram file system, which later can be mounted.
OPTIONS¶
- -v
- Enable verbose messaging.
- -E
- Treat all warnings as errors, which are reflected as command return
value.
- -b blocksize
- Use defined block size, which has to be divisible by page size.
- -e edition
- Use defined file system edition number in superblock.
- -N big, little, host
- Use defined endianness. Value defaults to host.
- -i file
- Insert a file to cramfs file system.
- -n name
- Set name of the cramfs file system.
- -p
- Pad by 512 bytes for boot code.
- -s
- This option is ignored. Originally the -s turned on directory entry
sorting.
- -z
- Make explicit holes. Use of this option will require 2.3.39 kernel, or
newer.
- -V
- Display version information and exit.
- -h
- Display help and exit.
EXIT STATUS¶
- 0
- success
- 8
- operation error, such as unable to allocate memory
SEE ALSO¶
mount(8),
fsck.cramfs(8)
AVAILABILITY¶
The example command is part of the util-linux package and is available from
Linux
Kernel Archive