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.  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  ftp://ftp.kernel.org/pub/linux/utils/util-
   linux/.

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