Patent ID: 7039668

Claim:
A directory server system comprising: a directory server for storing an attribute of an entry; an entity monitor connected to said directory server for monitoring an entity, so that if a change in a state of said entity appears, then said entity monitor instructs said directory server to renew an attribute of a corresponding entry to said entity; a directory renewal history storage device connected to said directory server for storing a renewed attribute of said entry as attribute renewal history information; a time-correspondent directory server connected to both said directory server and said directory renewal history storage device for confirming an existence of a target entry on said directory server, so that if said existence of said target entry on said directory server could be confirmed, then said time-correspondent directory server obtains said attribute renewal history information from said directory renewal history storage device; a directory purging entry storage device connected to said directory server, said directory renewal history storage device and said time-correspondent directory server for storing an entry corresponding to an absent entity which has become absent from said directory server, wherein if said entity becomes absent, then said attribute renewal history information of a corresponding entry to said absent entity is deleted from said directory renewal history storage device and stored in said directory purging entry storage device.