DBMS_PIPE:

Package DBMS_PIPE permits different sessions to communicate over named pipes. (A pipe is an area of memory used through one process to pass information to another.) The procedures pack_message & send_message can be used to pack a message into a pipe then send it to another session in the similar instance.

At the other end of the pipe, the procedures receive_message &unpack_message can be used to receive and unpack (read) the message. Named pipes are useful in various ways.

For instance, you can write routines in C which permits external servers to collect information, and then send it via pipes to procedures stored in an Oracle database.