MKFS.CRAMFS(8)                                                 System Administration                                                MKFS.CRAMFS(8)

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.

       -h, --help
              Display help text and exit.

       -V, --version
              Display version information and exit.

EXIT STATUS

              0      success
              8      operation error, such as unable to allocate memory

SEE ALSO

       fsck.cramfs(8), mount(8)

AVAILABILITY

       The example command is part of the util-linux package and is available from Linux  Kernel  Archive  <https://www.kernel.org/pub/linux/utils
       /util-linux/>.

util-linux                                                          April 2013                                                      MKFS.CRAMFS(8)