When I do:ls -a / on Fedora 21 there is a hidden file named:.readahead and it's 104092kWhat is this file?.... is it suppose to be there?I found this on google:readahead system call on wiki.Excerpt:readahead is a system call of the Linux kernel that loads a file's  contents into the page cache, providing that way a file prefetching  technology. When a file is subsequently accessed, its contents are  read from the main memory (RAM) rather than from a hard disk drive  (HDD), resulting in much lower file access latencies due to much  higher performance of the main memory.More on the readahead system call from man:Excerpt:readahead() initiates readahead on a file so that subsequent reads         from that file will be satisfied from the cache, and not block on         disk I/O (assuming the readahead was initiated early enough and that         other activity on the system did not in the meantime flush pages from         the cache).The only hit for this particular file was this mailing-list:http://linux.derkeiler.comExcerpt:Indeed those files appear to be misplaced, the .config directory look  like a leftover from the installation.. and the .readahead file  appears to be written at boot time, dunno what writes it, monitoring  it with audit may yield some clues.File a bug report.
What is this file: .readahead doing in my root directory?
files;root;root filesystem