Saying Y here includes support for CramFs (Compressed ROM File System). CramFs is designed to be a simple, small, and compressed file system for ROM based embedded systems. CramFs is read-only, limited to 256MB file systems (with 16MB files), and doesn't support 16/32 bits uid/gid, hard links and timestamps. See <file:Documentation/filesystems/cramfs.txt> and <file:fs/cramfs/README> for further information. To compile this as a module, choose M here: the module will be called cramfs. Note that the root file system (the one containing the directory /) cannot be compiled as a module. If unsure, say N.