Informix IDS provide following modes:-
1)Online mode -> This is the normal operating mode of the database server.
2)Offline mode? -> The database server is not running. Shared memory is not allocated.
3)Quiescent mode -> This is the normal operating mode of the database server.
Administrators use this mode to perform maintenance functions that do not require the execution of SQL and DDL statements.
Only the administrator (user informix) can access the database
4)Single-User mode -> This mode is an intermediary mode between Quiescent mode and Online mode?
Administrators use this mode to perform any maintenance task, including tasks requiring the execution of SQL and DDL statements. Administrators can also perform all other functions available inOnline mode. You can see the current database server mode by executing the onstat - utility from the command.