Editing Reference counting (section)

===File systems===
Many file systems maintain reference counts to any particular block or file, for example the [[inode]] ''link count'' on [[Unix filesystem|Unix-style file systems]], which are usually known as [[hard links]]. When the count reaches zero, the file can be safely deallocated. While references can still be made from [[directory (file systems)|directories]], some Unixes only allow references from live processes, and there can be files that exist outside the file system hierarchy.