simple interprocess messaging system (system message bus)

 D-Bus is a message bus, used for sending messages between applications.
 Conceptually, it fits somewhere in between raw sockets and CORBA in
 terms of complexity.
 .
 D-Bus supports broadcast messages, asynchronous messages (thus
 decreasing latency), authentication, and more. It is designed to be
 low-overhead; messages are sent using a binary protocol, not using
 XML. D-Bus also supports a method call mapping for its messages, but
 it is not required; this makes using the system quite simple.
 .
 It comes with several bindings, including GLib, Python, Qt and Java.
 .
 This package provides a fully-functional D-Bus system bus with activation
 support, used for communication between system services, and depends on
 most of the other components of the reference implementation of D-Bus.
 .
 To provide a complete D-Bus session bus, install one of the packages
 that implement the dbus-session-bus virtual package, such as
 dbus-user-session. The recommended implementation is indicated by
 the default-dbus-session-bus virtual package.