2 tristate "Compressed ROM file system support (cramfs)"
5 Saying Y here includes support for CramFs (Compressed ROM File
6 System). CramFs is designed to be a simple, small, and compressed
7 file system for ROM based embedded systems. CramFs is read-only,
8 limited to 256MB file systems (with 16MB files), and doesn't support
9 16/32 bits uid/gid, hard links and timestamps.
11 See <file:Documentation/filesystems/cramfs.txt> and
12 <file:fs/cramfs/README> for further information.
14 To compile this as a module, choose M here: the module will be called
15 cramfs. Note that the root file system (the one containing the
16 directory /) cannot be compiled as a module.
18 This filesystem is limited in capabilities and performance on
19 purpose to remain small and low on RAM usage. It is most suitable
20 for small embedded systems. If you have ample RAM to spare, you may
21 consider a more capable compressed filesystem such as SquashFS
22 which is much better in terms of performance and features.
26 config CRAMFS_BLOCKDEV
27 bool "Support CramFs image over a regular block device" if EXPERT
28 depends on CRAMFS && BLOCK
31 This option allows the CramFs driver to load data from a regular
32 block device such a disk partition or a ramdisk.
35 bool "Support CramFs image directly mapped in physical memory"
36 depends on CRAMFS && CRAMFS <= MTD
37 default y if !CRAMFS_BLOCKDEV
39 This option allows the CramFs driver to load data directly from
40 a linear adressed memory range (usually non volatile memory
41 like flash) instead of going through the block device layer.
42 This saves some memory since no intermediate buffering is
45 The location of the CramFs image is determined by a
46 MTD device capable of direct memory mapping e.g. from
47 the 'physmap' map driver or a resulting MTD partition.
48 For example, this would mount the cramfs image stored in
49 the MTD partition named "xip_fs" on the /mnt mountpoint:
51 mount -t cramfs mtd:xip_fs /mnt