CLOCKSS: Open Journal Systems also supports the CLOCKSS (Controlled Many Copies Keep Stuff Safe) system to ensure a secure and permanent archive for the journal. CLOCKSS is based on the open-source LOCKSS software developed at Stanford University Library, which enables libraries to preserve selected web journals by regularly polling registered journal websites for newly published content and archiving it. Each archive is continually validated against other library caches, and if content is corrupted or lost, the other caches or the journal restores it.